Copyright © 1997, 1998, 1999 by the PHP Documentation Group
Copyright
This manual is © Copyright 1997, 1998, 1999 the PHP Documentation Group. The members of this group are listed on the front page of this manual.
This manual can be redistributed under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
Date: 1999-08-07
PHP is an HTML-embedded scripting language. Much of its syntax is borrowed from C, Java and Perl with a couple of unique PHP-specific features thrown in. The goal of the language is to allow web developers to write dynamically generated pages quickly.
This manual is written in SGML using the DocBook DTD, using DSSSL (Document Style and Semantics Specification Language) for formatting. The tools used for formatting HTML, TeX and RTF versions are Jade, written by James Clark and The Modular DocBook Stylesheets written by Norman Walsh. PHP's documentation framework was assembled by Stig Sæther Bakken.
PHP is a server-side HTML-embedded scripting language.
Simple answer, but what does that mean? An example:
Example 1-1. An introductory example <html>
<head>
<title>Example</title>
</head>
<body>
<?php echo "Hi, I'm a PHP script!"; ?>
</body>
</html>
|
Notice how this is different from a CGI script written in other languages like Perl or C -- instead of writing a program with lots of commands to output HTML, you write an HTML script with a some embedded code to do something (in this case, output some text). The PHP code is enclosed in special start and end tags that allow you to jump into and out of "PHP mode".
What distinguishes PHP from something like client-side Javascript is that the code is executed on the server. If you were to have a script similar to the above on your server, the client would receive the results of running that script, with no way of determining what the underlying code may be. You can even configure your web server to process all your HTML files with PHP, and then there's really no way that users can tell what you have up your sleeve.
At the most basic level, PHP can do anything any other CGI program can do, such as collect form data, generate dynamic page content, or send and receive cookies.
Perhaps the strongest and most significant feature in PHP is its support for a wide range of databases. Writing a database-enabled web page is incredibly simple. The following databases are currently supported:
Adabas D InterBase Solid dBase mSQL Sybase Empress MySQL Velocis FilePro Oracle Unix dbm Informix PostgreSQL
PHP also has support for talking to other services using protocols such as IMAP, SNMP, NNTP, POP3, or even HTTP. You can also open raw network sockets and interact using other protocols.
PHP was conceived sometime in the fall of 1994 by Rasmus Lerdorf. Early non-released versions were used on his home page to keep track of who was looking at his online resume. The first version used by others was available sometime in early 1995 and was known as the Personal Home Page Tools. It consisted of a very simplistic parser engine that only understood a few special macros and a number of utilities that were in common use on home pages back then. A guestbook, a counter and some other stuff. The parser was rewritten in mid-1995 and named PHP/FI Version 2. The FI came from another package Rasmus had written which interpreted html form data. He combined the Personal Home Page tools scripts with the Form Interpreter and added mSQL support and PHP/FI was born. PHP/FI grew at an amazing pace and people started contributing code to it.
It is hard to give any hard statistics, but it is estimated that by late 1996 PHP/FI was in use on at least 15,000 web sites around the world. By mid-1997 this number had grown to over 50,000. Mid-1997 also saw a change in the development of PHP. It changed from being Rasmus' own pet project that a handful of people had contributed to, to being a much more organized team effort. The parser was rewritten from scratch by Zeev Suraski and Andi Gutmans and this new parser formed the basis for PHP Version 3. A lot of the utility code from PHP/FI was ported over to PHP3 and a lot of it was completely rewritten.
Today (mid-1999) either PHP/FI or PHP3 ships with a number of commercial products such as C2's StrongHold web server and RedHat Linux and a conservative estimate based on an extrapolation from numbers provided by NetCraft would be that PHP is in use on over 150,000 sites around the world. To put that in perspective, that is more sites than run Netscape's flagship Enterprise server on the Internet.
Also as of this writing, work is underway on the next generation of PHP that will utilize the powerful Zend scripting engine to deliver higher performance, and will also support running under webservers other than Apache as a native server module.
The source code, and binary distributions for some platforms (including Windows), can be found at http://www.php.net/.
This section will guide you through the configuration and installation of PHP. Prerequisite knowledge and software:
Basic UNIX skills (being able to operate "make" and a C compiler)
An ANSI C compiler
A web server
1. gunzip apache_1.3.x.tar.gz
2. tar xvf apache_1.3.x.tar
3. gunzip php-3.0.x.tar.gz
4. tar xvf php-3.0.x.tar
5. cd apache_1.3.x
6. ./configure --prefix=/www
7. cd ../php-3.0.x
8. ./configure --with-mysql --with-apache=../apache_1.3.x --enable-track-vars
9. make
10. make install
11. cd ../apache_1.3.x
12. ./configure --prefix=/www --activate-module=src/modules/php3/libphp3.a
13. make
14. make install
Instead of this step you may prefer to simply copy the httpd binary
overtop of your existing binary. Make sure you shut down your
server first though.
15. cd ../php-3.0.x
16. cp php3.ini-dist /usr/local/lib/php3.ini
You can edit /usr/local/lib/php3.ini file to set PHP options. If
you prefer this file in another location, use
--with-config-file-path=/path in step 8.
17. Edit your httpd.conf or srm.conf file and add:
AddType application/x-httpd-php3 .php3
You can choose any extension you wish here. .php3 is simply the one
we suggest.
18. Use your normal procedure for starting the Apache server. (You must
stop and restart the server, not just cause the server to reload by
use a HUP or USR1 signal.)
There are two ways of configuring PHP.
Using the "setup" script that comes with PHP. This script asks you a series of questions (almost like the "install" script of PHP/FI 2.0) and runs "configure" in the end. To run this script, type ./setup.
This script will also create a file called "do-conf", this file will contain the options passed to configure. You can edit this file to change just a few options without having to re-run setup. Then type ./do-conf to run configure with the new options.
Running configure by hand. To see what options you have, type ./configure --help.
Details about some of the different configuration options are listed below.
To build PHP as an Apache module, answer "yes" to "Build as an Apache module?" (the --with-apache=DIR option to configure) and specify the Apache distribution base directory. If you have unpacked your Apache distribution in /usr/local/www/apache_1.2.4, this is your Apache distribution base directory. The default directory is /usr/local/etc/httpd.
To build PHP as an fhttpd module, answer "yes" to "Build as an fhttpd module?" (the --with-fhttpd=DIR option to configure) and specify the fhttpd source base directory. The default directory is /usr/local/src/fhttpd. If you are running fhttpd, building PHP as a module will give better performance, more control and remote execution capability.
The default is to build PHP as a CGI program. If you are running a web server PHP has module support for, you should generally go for that solution for performance reasons. However, the CGI version enables Apache users to run different PHP-enabled pages under different user-ids. Please make sure you read through the Security chapter if you are going to run PHP as a CGI.
PHP has native support for a number of databases (as well as ODBC):
--with-adabas=DIR
Compiles with Adabas D support. The parameter is the Adabas D install directory and defaults to /usr/local/adabasd.
--with-filepro
Enables the bundled read-only filePro support. No external libraries are required.
--with-msql=DIR
Enables mSQL support. The parameter to this option is the mSQL install directory and defaults to /usr/local/Hughes. This is the default directory of the mSQL 2.0 distribution. configure automatically detects which mSQL version you are running and PHP supports both 1.0 and 2.0, but if you compile PHP with mSQL 1.0, you can only access mSQL 1.0 databases, and vice-versa.
See also mSQL Configuration Directives in the configuration file.
--with-mysql=DIR
Enables MySQL support. The parameter to this option is the MySQL install directory and defaults to /usr/local. This is the default installation directory of the MySQL distribution.
See also MySQL Configuration Directives in the configuration file.
--with-iodbc=DIR
Includes iODBC support. This feature was first developed for iODBC Driver Manager, a freely redistributable ODBC driver manager which runs under many flavors of UNIX. The parameter to this option is the iODBC installation directory and defaults to /usr/local.
--with-openlink=DIR
Includes OpenLink ODBC support. The parameter to this option is the OpenLink ODBC installation directory and defaults to /usr/local/openlink.
--with-oracle=DIR
Includes Oracle support. Has been tested and should be working at least with Oracle versions 7.0 through 7.3. The parameter is the ORACLE_HOME directory. You do not have to specify this parameter if your Oracle environment has been set up.
--with-pgsql=DIR
Includes PostgreSQL support. The parameter is the PostgreSQL base install directory and defaults to /usr/local/pgsql.
See also Postgres Configuration Directives in the configuration file.
--with-solid=DIR
Includes Solid support. The parameter is the Solid install directory and defaults to /usr/local/solid.
--with-sybase=DIR
Includes Sybase support. The parameter is the Sybase install directory and defaults to /home/sybase.
See also Sybase Configuration Directives in the configuration file.
--with-sybase-ct=DIR
Includes Sybase-CT support. The parameter is the Sybase-CT install directory and defaults to /home/sybase.
See also Sybase-CT Configuration Directives in the configuration file.
--with-velocis=DIR
Includes Velocis support. The parameter is the Velocis install directory and defaults to /usr/local/velocis.
--with-custom-odbc=DIR
Includes support for an arbitrary custom ODBC library. The parameter is the base directory and defaults to /usr/local.
This option implies that you have defined CUSTOM_ODBC_LIBS when you run the configure script. You also must have a valid odbc.h header somewhere in your include path. If you don't have one, create it and include your specific header from there. Your header may also require some extra definitions, particularly when it is multiplatform. Define them in CFLAGS.
For example, you can use Sybase SQL Anywhere on QNX as following: CFLAGS=-DODBC_QNX LDFLAGS=-lunix CUSTOM_ODBC_LIBS="-ldblib -lodbc" ./configure --with-custom-odbc=/usr/lib/sqlany50
--disable-unified-odbc
Disables the Unified ODBC module, which is a common interface to all the databases with ODBC-based interfaces, such as Solid and Adabas D. It also works for normal ODBC libraries. Has been tested with iODBC, Solid, Adabas D and Sybase SQL Anywhere. Requires that one (and only one) of these modules or the Velocis module is enabled, or a custom ODBC library specified. This option is only applicable if one of the following options is used: --with-iodbc, --with-solid, --with-adabas, --with-velocis, or --with-custom-odbc,
See also Unified ODBC Configuration Directives in the configuration file.
--with-mcrypt
Include support for the mcrypt library. See the mcrypt documentation for more information. If you use the optional DIR argument, PHP will look for mcrypt.h in DIR/include.
--enable-sysvsem
Include support for Sys V semaphores (supported by most Unix derivates). See the Semaphore and Shared Memory documentation for more information.
--enable-sysvshm
Include support for Sys V shared memory (supported by most Unix derivates). See the Semaphore and Shared Memory documentation for more information.
--with-xml
Include support for a non-validating XML parser using James Clark's expat library. See the XML function reference for details.
--enable-maintainer-mode
Turns on extra dependencies and compiler warnings used by some of the PHP developers.
--with-system-regex
Uses the system's regular expression library rather than the bundled one. If you are building PHP as a server module, you must use the same library when building PHP as when linking the server. Enable this if the system's library provides special features you need. It is recommended that you use the bundled library if possible.
--with-config-file-path=DIR
The path used to look for the configuration file when PHP starts up.
--with-exec-dir=DIR
Only allow running of executables in DIR when in safe mode. Defaults to /usr/local/bin. This option only sets the default, it may be changed with the safe_mode_exec_dir directive in the configuration file later.
--enable-debug
Enables extra debug information. This makes it possible to gather more detailed information when there are problems with PHP. (Note that this doesn't have anything to do with debugging facilities or information available to PHP scripts.)
--enable-safe-mode
Enables "safe mode" by default. This imposes several restrictions on what PHP can do, such as opening only files within the document root. Read the Security chapter for more more information. CGI users should always enable secure mode. This option only sets the default, it may be enabled or disabled with the safe_mode directive in the configuration file later.
--enable-track-vars
Makes PHP keep track of where GET/POST/cookie variables come from in the arrays HTTP_GET_VARS, HTTP_POST_VARS and HTTP_COOKIE_VARS. This option only sets the default, it may be enabled or disabled with the track_vars directive in the configuration file later.
--enable-magic-quotes
Enable magic quotes by default. This option only sets the default, it may be enabled or disabled with the magic_quotes_runtime directive in the configuration file later. See also the magic_quotes_gpc and the magic_quotes_sybase directives.
--enable-debugger
Enables the internal PHP debugger support. This feature is still in an experimental state. See also the Debugger Configuration directives in the configuration file.
--enable-discard-path
If this is enabled, the PHP CGI binary can safely be placed outside of the web tree and people will not be able to circumvent .htaccess security. Read the section in the security chapter about this option.
--enable-bcmath
Enables bc style arbitrary precision math functions. See also the bcmath.scale option in the configuration file.
--enable-force-cgi-redirect
Enable the security check for internal server redirects. You should use this if you are running the CGI version with Apache.
When using PHP as a CGI binary, PHP by default always first checks that it is used by redirection (for example under Apache, by using Action directives). This makes sure that the PHP binary cannot be used to bypass standard web server authentication procedures by calling it directly, like http://my.host/cgi-bin/php/secret/doc.html. This example accesses http://my.host/secret/doc.html but does not honour any security settings enforced by httpd for directory /secret.
Not enabling option disables the check and enables bypassing httpd security and authentication settings. Do this only if your server software is unable to indicate that a safe redirection was done and all your files under your document root and user directories may be accessed by anyone.
Read the section in the security chapter about this option.
--disable-short-tags
Disables the short form <? ?> PHP tags. You must disable the short form if you want to use PHP with XML. With short tags disabled, the only PHP code tag is <?php ?>. This option only sets the default, it may be enabled or disabled with the short_open_tag directive in the configuration file later.
--enable-url-includes
Makes it possible to run code on other HTTP or FTP servers directly from PHP with include(). See also the include_path option in the configuration file.
To make the PHP installation look for header or library files in different directories, modify the CPPFLAGS and LDFLAGS environment variables, respectively. If you are using a sensible shell, you should be able to do LDFLAGS=-L/my/lib/dir CPPFLAGS=-I/my/include/dir ./configure
When PHP is configured, you are ready to build the CGI executable or the PHP library. The command make should take care of this. If it fails and you can't figure out why, see the Problems section.
If you have built PHP as a CGI program, you may test your build by typing make test. It is always a good idea to test your build. This way you may catch a problem with PHP on your platform early instead of having to struggle with it later.
If you have built PHP as a CGI program, you may benchmark your build by typing make bench. Note that if safe mode is on by default, the benchmark may not be able to finish if it takes longer then the 30 seconds allowed. This is because the set_time_limit() can not be used in safe mode. Use the max_execution_time configuration setting to control this time for you own scripts. make bench ignores the configuration file.
This install guide will help you install and configure PHP on your Windows 9x/NT webservers. This guide was compiled by Bob Silva. The latest revision can be found at http://www.umesd.k12.or.us/php/win32install.html.
This guide provides installation support for:
Personal Web Server (Newest version recommended)
Internet Information Server 3 or 4
Apache 1.3.x
Omni HTTPd 2.0b1
The following steps should be performed on all installations before the server specific instructions.
Extract the distribution file to a directory of your choice. "C:\PHP3\" is a good start.
Copy the file, 'php3-dist.ini' to your '%WINDOWS%' directory and rename it to 'php3.ini'. Your '%WINDOWS%' directory is typically:
| c:\windows for Windows 95/98 |
| c:\winnt or c:\winnt40 for NT servers |
Edit your 'php3.ini' file:
You will need to change the 'extension_dir' setting to point to your php-install-dir, or where you have placed your 'php3_*.dll' files. ex: c:\php3
If you are using Omni Httpd, do not follow the next step. Set the 'doc_root' to point to your webservers document_root. ex: c:\apache\htdocs or c:\webroot
Choose which modules you would like to load when PHP starts. You can uncomment the: 'extension=php3_*.dll' lines to load these modules. Some modules require you to have additional libraries installed on your system for the module to work correctly. The PHP FAQ has more information on where to get supporting libraries. You can also load a module dynamically in your script using: dl("php_*.dll");
On PWS and IIS, you can set the browscap.ini to point to: 'c:\windows\system\inetsrv\browscap.ini' on Windows 95/98 and 'c:\winnt\system32\inetsrv\browscap.ini' on NT Server. Additional information on using the browscap functionality in PHP can be found at this mirror, select the "source" button to see it in action.
The DLLs for PHP extensions are prefixed with 'php3_'. This prevents confusion between PHP extensions and their supporting libraries.
The recommended method for configuring these servers is to use the INF file included with the distribution (php_iis_reg.inf). You may want to edit this file and make sure the extensions and PHP install directories match your configuration. Or you can follow the steps below to do it manually.
WARNING: These steps involve working directly with the windows registry. One error here can leave your system in an unstable state. We highly recommend that you back up your registry first. The PHP Development team will not be held responsible if you damage your registry.
Run Regedit.
Navigate to: HKEY_LOCAL_MACHINE /System /CurrentControlSet /Services /W3Svc /Parameters /ScriptMap.
On the edit menu select: New->String Value.
Type in the extension you wish to use for your php scripts. ex: .php3
Double click on the new string value and enter the path to php.exe in the value data field. ex: c:\php3\php.exe %s %s. The '%s %s' is VERY important, PHP will not work properly without it.
Repeat these steps for each extension you wish to associate with PHP scripts.
Now navigate to: HKEY_CLASSES_ROOT
On the edit menu select: New->Key.
Name the key to the extension you setup in the previous section. ex: .php3
Highlight the new key and in the right side pane, double click the "default value" and enter phpfile.
Repeat the last step for each extension you set up in the previous section.
Now create another New->Key under HKEY_CLASSES_ROOT and name it phpfile.
Highlight the new key phpfile and in the right side pane, double click the "default value" and enter PHP Script.
Right click on the phpfile key and select New->Key, name it Shell.
Right click on the Shell key and select New->Key, name it open.
Right click on the open key and select New->Key, name it command.
Highlight the new key command and in the right side pane, double click the "default value" and enter the path to php.exe. ex: c:\php3\php.exe -q %1. (don't forget the %1).
Exit Regedit.
PWS and IIS 3 users now have a fully operational system. IIS 3 users can use a nifty tool from Steven Genusa to configure their script maps.
To install PHP on an NT Server running IIS 4, follow these instructions:
In Internet Service Manager (MMC), select the Web site or the starting point directory of an application.
Open the directory's property sheets (by right clicking and selecting properties), and then click the Home Directory, Virtual Directory, or Directory tab.
Click the Configuration button, and then click the App Mappings tab.
Click Add, and in the Executable box, type: c:\path-to-php-dir\php.exe %s %s. You MUST have the %s %s on the end, PHP will not function properly if you fail to do this.
In the Extension box, type the file name extension you want associated with PHP scripts. (You must repeat step 5 and 6 for each extension you want accociated with PHP scripts. (.php3 and .phtml are common)
Set up the appropriate security. (This is done in Internet Service Manager), and if your NT Server uses NTFS file system, add execute rights for I_USR_ to the directory that contains php.exe.
You must edit your srm.conf or httpd.conf to configure Apache to work with the PHP CGI binary.
Although there can be a few variations of configuring PHP under Apache, this one is simple enough to be used by the newcomer. Please consult the Apache Docs for further configuration directives.
ScriptAlias /php3/ "c:/path-to-php-dir/"
AddType application/x-httpd-php3 .php3
AddType application/x-httpd-php3 .phtml
Action application/x-httpd-php3 "/php3/php.exe"
To use the source code highlighting feature, simply create a PHP script file and stick this code in: <?php show_source ("original_php_script.php3"); ?>. Substitute original_php_script.php3 with the name of the file you wish to show the source of. (this is only one way of doing it). Note: On Win-Apache all back slashes in a path statement such as: "c:\directory\file.ext", must be converted to forward slashes.
This has got to be the easiest config there is:
| Step 1: Install Omni server |
| Step 2: Right click on the blue OmniHTTPd icon in the system tray and select Properties |
| Step 3: Click on Web Server Global Settings |
| Step 4: On the 'External' tab, enter: virtual = .php3 | actual = c:\path-to-php-dir\php.exe |
| Step 5: On the Mime tab, enter: virtual = wwwserver/stdcgi | actual = .php3 |
| Step 6: Click OK |
Repeat steps 2 - 6 for each extension you want to associate with PHP.
Table 2-1. PHP Modules
| php3_calendar.dll | Calendar conversion functions |
| php3_crypt.dll | Crypt functions |
| php3_dbase.dll | DBase functions |
| php3_dbm.dll | GDBM emulation via Berkely DB2 library |
| php3_filepro.dll | READ ONLY access to filepro databases |
| php3_gd.dll | GD Library functions for gif manipulation |
| php3_hyperwave.dll | HyperWave functions |
| php3_imap4r2.dll | IMAP 4 functions |
| php3_ldap.dll | LDAP functions |
| php3_msql1.dll | mSQL 1 client |
| php3_msql2.dll | mSQL 2 client |
| php3_mssql.dll | MSSQL client (requires MSSQL DB-Libraries |
| php3_mysql.dll | MySQL functions |
| php3_nsmail.dll | Netscape mail functions |
| php3_oci73.dll | Oracle functions |
| php3_snmp.dll | SNMP get and walk functions (NT only!) |
| php3_zlib.dll | ZLib functions |
Some problems are more common than others. The most common ones are listed in the PHP FAQ, found at http://www.php.net/FAQ.php3
If you think you have found a bug in PHP, please report it. The PHP developers probably don't know about it, and unless you report it, chances are it won't be fixed. You can report bugs using the bug-tracking system at http://www.php.net/bugs.php3.
If you are still stuck, someone on the PHP mailing list may be able to help you. You should check out the archive first, in case someone already answered someone else who had the same problem as you. The archives are available from the support page on http://www.php.net/. To subscribe to the PHP mailing list, send an empty mail to php3-subscribe@lists.php.net. The mailing list address is php3@lists.php.net.
If you want to get help on the mailing list, please try to be precise and give the necessary details about your environment (which operating system, what PHP version, what web server, if you are running PHP as CGI or a server module, etc.), and preferably enough code to make others able to reproduce and test your problem.
The configuration file (called php3.ini in PHP 3.0, and simply php.ini as of PHP 4.0) is read when PHP starts up. For the server module versions of PHP, this happens only once when the web server is started. For the CGI version, it happens on every invocation.
When using PHP as an Apache module, you can also change the configuration settings using directives in Apache configuration files and .htaccess files.
With PHP 3.0, there are Apache directives that correspond to each configuration setting in the php3.ini name, except the name is prefixed by "php3_".
With PHP 4.0, there are just a few Apache directives that allow you to change the PHP configuration settings.
This sets the value of the specified variable.
This is used to set a Boolean configuration option.
This sets the value of the specified variable. "Admin" configuration settings can only be set from within the main Apache configuration files, and not from .htaccess files.
This is used to set a Boolean configuration option.
You can view the settings of the configuration values in the output of phpinfo(). You can also access the values of individial configuration settings using get_cfg_var().
Specifies the name of a file that is automatically parsed after the main file. The file is included as if it was called with the include() function, so include_path is used.
The special value none disables auto-appending.
Note: If the script is terminated with exit(), auto-append will not occur.
Specifies the name of a file that is automatically parsed before the main file. The file is included as if it was called with the include() function, so include_path is used.
The special value none disables auto-prepending.
This determines whether errors should be printed to the screen as part of the HTML output or not.
PHP's "root directory" on the server. Only used if non-empty. If PHP is configured with safe mode, no files outside this directory are served.
This directive is really only useful in the Apache module version of PHP. It is used by sites that would like to turn PHP parsing on and off on a per-directory or per-virtual server basis. By putting php3_engine off in the appropriate places in the httpd.conf file, PHP can be enabled or disabled.
Name of file where script errors should be logged. If the special value syslog is used, the errors are sent to the system logger instead. On UNIX, this means syslog(3) and on Windows NT it means the event log. The system logger is not supported on Windows 95.
Set the error reporting level. The parameter is an integer representing a bit field. Add the values of the error reporting levels you want.
Table 3-1. Error Reporting Levels
| bit value | enabled reporting |
|---|---|
| 1 | normal errors |
| 2 | normal warnings |
| 4 | parser errors |
| 8 | non-critical style-related warnings |
Limit the files that can be opened by PHP to the specified directory-tree.
When a script tries to open a file with, for example, fopen or gzopen, the location of the file is checked. When the file is outside the specified directory-tree, PHP will refuse to open it. All symbolic links are resolved, so it's not possible to avoid this restriction with a symlink.
The special value . indicates that the directory in which the script is stored will be used as base-directory.
Under Windows, separate the directories with a semicolon. On all other systems, separate the directories with a colon. As an Apache module, open_basedir paths from parent directories are now automatically inherited.
Note: Support for multiple directories was added in 3.0.7.
The default is to allow all files to be opened.
Set the order of GET/POST/COOKIE variable parsing. The default setting of this directive is "GPC". Setting this to "GP", for example, will cause PHP to completely ignore cookies and to overwrite any GET method variables with POST-method variables of the same name.
Off by default. If changed to On scripts will run to completion even if the remote client disconnects in the middle. See also ignore_user_abort().
Specifies a list of directories where the require(), include() and fopen_with_path() functions look for files. The format is like the system's PATH environment variable: a list of directories separated with a colon in UNIX or semicolon in Windows.
Example 3-1. UNIX include_path include_path=.:/home/httpd/php-lib |
Example 3-2. Windows include_path include_path=".;c:\www\phplib" |
Tells whether script error messages should be logged to the server's error log. This option is thus server-specific.
Sets the magic_quotes state for GPC (Get/Post/Cookie) operations. When magic_quotes are on, all ' (single-quote), " (double quote), \ (backslash) and NUL's are escaped with a backslash automatically. If magic_quotes_sybase is also on, a single-quote is escaped with a single-quote instead of a backslash.
If magic_quotes_runtime is enabled, most functions that return data from any sort of external source including databases and text files will have quotes escaped with a backslash. If magic_quotes_sybase is also on, a single-quote is escaped with a single-quote instead of a backslash.
If magic_quotes_sybase is also on, a single-quote is escaped with a single-quote instead of a backslash if magic_quotes_gpc or magic_quotes_runtime is enabled.
This sets the maximum time in seconds a script is allowed to take before it is terminated by the parser. This helps prevent poorly written scripts from tieing up the server.
This sets the maximum amount of memory in bytes that a script is allowed to allocate. This helps prevent poorly written scripts for eating up all available memory on a server.
Tells whether the short form (<? ?>of PHP's open tag should be allowed. If you want to use PHP in combination with XML, you have to disable this option. If disabled, you must use the long form of the open tag (<?php ?>).
If enabled, the last error message will always be present in the global variable $php_errormsg.
If enabled, GET, POST and cookie input can be found in the global associative arrays $HTTP_GET_VARS, $HTTP_POST_VARS and $HTTP_COOKIE_VARS, respectively.
The temporary directory used for storing files when doing file upload. Must be writable by whatever user PHP is running as.
The base name of the directory used on a user's home directory for PHP files, for example public_html.
If enabled, this option makes PHP output a warning when the plus (+) operator is used on strings. This is to make it easier to find scripts that need to be rewritten to using the string concatenator instead (.).
DNS name or IP address of the SMTP server PHP under Windows should use for mail sent with the mail() function.
Which "From:" mail address should be used in mail sent from PHP under Windows.
Where the sendmail program can be found, usually /usr/sbin/sendmail or /usr/lib/sendmail configure does an honest attempt of locating this one for you and set a default, but if it fails, you can set it here.
Systems not using sendmail should set this directive to the sendmail wrapper/replacement their mail system offers, if any. For example, Qmail users can normally set it to /var/qmail/bin/sendmail.
Whether to enable PHP's safe mode. Read the Security chapter for more more information.
If PHP is used in safe mode, system() and the other functions executing system programs refuse to start programs that are not in this directory.
DNS name or IP address of host used by the debugger.
Port number used by the debugger.
Whether the debugger is enabled.
This directive is really only useful in the Apache module version of PHP. You can turn dynamic loading of PHP extensions with dl() on and off per virtual server or per directory.
The main reason for turning dynamic loading off is security. With dynamic loading, it's possible to ignore all the safe_mode and open_basedir restrictions.
The default is to allow dynamic loading, except when using safe-mode. In safe-mode, it's always imposible to use dl().
In what directory PHP should look for dynamically loadable extensions.
Which dynamically loadable extensions to load when PHP starts up.
Whether to allow persistent MySQL connections.
The maximum number of persistent MySQL connections per process.
The maximum number of MySQL connections per process, including persistent connections.
Whether to allow persistent mSQL connections.
The maximum number of persistent mSQL connections per process.
The maximum number of mSQL connections per process, including persistent connections.
Whether to allow persistent Postgres connections.
The maximum number of persistent Postgres connections per process.
The maximum number of Postgres connections per process, including persistent connections.
Whether to allow persistent Sybase connections.
The maximum number of persistent Sybase connections per process.
The maximum number of Sybase connections per process, including persistent connections.
Whether to allow persistent Sybase-CT connections. The default is on.
The maximum number of persistent Sybase-CT connections per process. The default is -1 meaning unlimited.
The maximum number of Sybase-CT connections per process, including persistent connections. The default is -1 meaning unlimited.
Server messages with severity greater than or equal to sybct.min_server_severity will be reported as warnings. This value can also be set from a script by calling sybase_min_server_severity(). The default is 10 which reports errors of information severity or greater.
Client library messages with severity greater than or equal to sybct.min_client_severity will be reported as warnings. This value can also be set from a script by calling sybase_min_client_severity(). The default is 10 which effectively disables reporting.
The maximum time in seconds to wait for a connection attempt to succeed before returning failure. Note that if max_execution_time has been exceeded when a connection attempt times out, your script will be terminated before it can take action on failure. The default is one minute.
The maximum time in seconds to wait for a select_db or query operation to succeed before returning failure. Note that if max_execution_time has been exceeded when am operation times out, your script will be terminated before it can take action on failure. The default is no limit.
The name of the host you claim to be connecting from, for display by sp_who. The default is none.
Whether to allow persistent Informix connections.
The maximum number of persistent Informix connections per process.
The maximum number of Informix connections per process, including persistent connections.
The default host to connect to when no host is specified in ifx_connect() or ifx_pconnect().
The default user id to use when none is specified in ifx_connect() or ifx_pconnect().
The default password to use when none is specified in ifx_connect() or ifx_pconnect().
Set to true if you want to return blob columns in a file, false if you want them in memory. You can override the setting at runtime with ifx_blobinfile_mode().
Set to true if you want to return TEXT columns as normal strings in select statements, false if you want to use blob id parameters. You can override the setting at runtime with ifx_textasvarchar().
Set to true if you want to return BYTE columns as normal strings in select queries, false if you want to use blob id parameters. You can override the setting at runtime with ifx_textasvarchar().
Set to true if you want to trim trailing spaces from CHAR columns when fetching them.
Set to true if you want to return NULL columns as the literal string "NULL", false if you want them returned as the empty string "". You can override this setting at runtime with ifx_nullformat().
Number of decimal digits for all bcmath functions.
ODBC data source to use if none is specified in odbc_connect() or odbc_pconnect().
User name to use if none is specified in odbc_connect() or odbc_pconnect().
Password to use if none is specified in odbc_connect() or odbc_pconnect().
Whether to allow persistent ODBC connections.
The maximum number of persistent ODBC connections per process.
The maximum number of ODBC connections per process, including persistent connections.
PHP is a powerful language and the interpreter, whether included in a web server as a module or executed as a separate CGI binary, is able to access files, execute commands and open network connections on the server. These properties make anything run on a web server insecure by default. PHP is designed specifically to be a more secure language for writing CGI programs than Perl or C, and with correct selection of compile-time and runtime configuration options it gives you exactly the combination of freedom and security you need.
As there are many different ways of utilizing PHP, there are many configuration options controlling its behaviour. A large selection of options guarantees you can use PHP for a lot of purposes, but it also means there are combinations of these options and server configurations that result in an insecure setup. This chapter explains the different configuration option combinations and the situations they can be safely used.
Using PHP as a CGI binary is an option for setups that for some reason do not wish to integrate PHP as a module into server software (like Apache), or will use PHP with different kinds of CGI wrappers to create safe chroot and setuid environments for scripts. This setup usually involves installing executable PHP binary to the web server cgi-bin directory. CERT advisory CA-96.11 recommends agains placing any interpreters into cgi-bin. Even if the PHP binary can be used as a standalone interpreter, PHP is designed to prevent the attacks this setup makes possible:
Accessing system files: http://my.host/cgi-bin/php?/etc/passwd
The query information in an url after the question mark (?) is passed as command line arguments to the interpreter by the CGI interface. Usually interpreters open and execute the file specified as the first argument on the command line.
When invoked as a CGI binary, PHP refuses to interpret the command line arguments.
Accessing any web document on server: http://my.host/cgi-bin/php/secret/doc.html
The path information part of the url after the PHP binary name, /secret/doc.html is conventionally used to specify the name of the file to be opened and interpreted by the CGI program. Usually some web server configuration directives (Apache: Action) are used to redirect requests to documents like http://my.host/secret/script.php3 to the PHP interpreter. With this setup, the web server first checks the access permissions to the directory /secret, and after that creates the redirected request http://my.host/cgi-bin/php/secret/script.php3. Unfortunately, if the request is originally given in this form, no access checks are made by web server for file /secret/script.php3, but only for the /cgi-bin/php file. This way any user able to access /cgi-bin/php is able to access any protected document on the web server.
In PHP, compile-time configuration option --enable-force-cgi-redirect and runtime configuration directives doc_root and user_dir can be used to prevent this attack, if the server document tree has any directories with access restrictions. See below for full explanation of different combinations.
If your server does not have any content that is not restricted by password or ip based access control, there is no need for these configuration options. If your web server does not allow you to do redirects, or the server does not have a way to communicate with the PHP binary that the request is a safely redirected request, you can specify the option --disable-force-cgi-redirect to the configure script. You still have to make sure your PHP scripts do not rely on one or another way of calling the script, neither by directly http://my.host/cgi-bin/php/dir/script.php3 nor by redirection http://my.host/dir/script.php3.
Redirection can be configured in Apache by using AddHandler and Action directives (see below).
This compile-time option prevents anyone from calling PHP directly with a url like http://my.host/cgi-bin/php/secretdir/script.php3. Instead, PHP will only parse in this mode if it has gone through a web server redirect rule.
Usually the redirection in the Apache configuration is done with the following directives:
Action php3-script /cgi-bin/php AddHandler php3-script .php3
This option has only been tested with the Apache web server, and relies on Apache to set the non-standard CGI environment variable REDIRECT_STATUS on redirected requests. If your web server does not support any way of telling if the request is direct or redirected, you cannot use this option and you must use one of the other ways of running the CGI version documented here.
To include active content, like scripts and executables, in the web server document directories is sometimes consider an insecure practice. If for some configuration mistake the scripts are not executed but displayed as usual HTML documents, this may result in leakage of intellectual property or security information like passwords. Therefore many sysadmins will prefer setting up another directory structure for scripts that is only accessible through the PHP CGI, and therefore always interpreted and not displayed as such.
Also if the method for making sure the requests are not redirected, as described in the previous section, is not available, it is necessary to set up a script doc_root that is different from web document root.
You can set the PHP script document root by the configuration directive doc_root in the configuration file, or you can set the environment variable PHP_DOCUMENT_ROOT. If it is set, the CGI version of PHP will always construct the file name to open with this doc_root and the path information in the request, so you can be sure no script is executed outside this directory (except for user_dir below).
Another option usable here is user_dir. When user_dir is unset, only thing controlling the opened file name is doc_root. Opening an url like http://my.host/~user/doc.php3 does not result in opening a file under users home directory, but a file called ~user/doc.php3 under doc_root (yes, a directory name starting with a tilde [~]).
If user_dir is set to for example public_php, a request like http://my.host/~user/doc.php3 will open a file called doc.php3 under the directory named public_php under the home directory of the user. If the home of the user is /home/user, the file executed is /home/user/public_php/doc.php3.
user_dir expansion happens regardless of the doc_root setting, so you can control the document root and user directory access separately.
A very secure option is to put the PHP parser binary somewhere outside of the web tree of files. In /usr/local/bin, for example. The only real downside to this option is that you will now have to put a line similar to:
#!/usr/local/bin/php
To get PHP to handle PATH_INFO and PATH_TRANSLATED information correctly with this setup, the php parser should be compiled with the --enable-discard-path configure option.
When PHP is used as an Apache module it inherits Apache's user permissions (typically those of the "nobody" user).
There are four ways of escaping from HTML and entering "PHP code mode":
Example 5-1. Ways of escaping from HTML 1. <? echo ("this is the simplest, an SGML processing instruction\n"); ?>
2. <?php echo("if you want to serve XML documents, do like this\n"); ?>
3. <script language="php">
echo ("some editors (like FrontPage) don't
like processing instructions");
</script>
4. <% echo ("You may optionally use ASP-style tags"); %>
<%= $variable; # This is a shortcut for "<%echo .." %>
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The first way is only available if short tags have been enabled (either by calling short_tags(), they are configured on using the short_tags run-time configuration setting, or they are enabled using the --enable-short-tags compile-time configuration setting.
The fourth way is only available if ASP-style tags have been enabled using either the asp_tags configuration setting or the --enable-asp-tags compile-time configuration setting.
Note: Support for ASP-style tags was added in 3.0.4.
The closing "bracket" for the block will include the immediately trailing newline if one is present.
Instructions are separated the same as in C or perl - terminate each statement with a semicolon.
The closing tag (?>) also implies the end of the statement, so the following are equivalent:
<?php
echo "This is a test";
?>
<?php echo "This is a test" ?>
PHP supports 'C', 'C++' and Unix shell-style comments. For example:
<?php
echo "This is a test"; // This is a one-line c++ style comment
/* This is a multi line comment
yet another line of comment */
echo "This is yet another test";
echo "One Final Test"; # This is shell-style style comment
?>
The "one-line" comment styles actually only comment to the end of the line or the current block of PHP code, whichever comes first.
<h1>This is an <?# echo "simple";?> example.</h1> <p>The header above will say 'This is an example'.
You should be careful not to nest 'C' style comments, which can happen when commenting out large blocks.
<?php
/*
echo "This is a test"; /* This comment will cause a problem */
*/
?>
PHP supports the following types:
The type of a variable is usually not set by the programmer; rather, it is decided at runtime by PHP depending on the context in which that variable is used.
If you would like to force a variable to be converted to a certain type, you may either cast the variable or use the settype() function on it.
Note that a variable may behave in different manners in certain situations, depending on what type it is a the time. For more information, see the section on Type Juggling.
Integers can be specified using any of the following syntaxes:
$a = 1234; # decimal number $a = -123; # a negative number $a = 0123; # octal number (equivalent to 83 decimal) $a = 0x12; # hexadecimal number (equivalent to 18 decimal)
Floating point numbers ("doubles") can be specified using any of the following syntaxes:
$a = 1.234; $a = 1.2e3;
Strings can be specified using one of two sets of delimiters.
If the string is enclosed in double-quotes ("), variables within the string will be expanded (subject to some parsing limitations). As in C and Perl, the backslash ("\") character can be used in specifying special characters:
Table 6-1. Escaped characters
| sequence | meaning |
|---|---|
| \n | newline |
| \r | carriage |
| \t | horizontal tab |
| \\ | backslash |
| \$ | dollar sign |
| \" | double-quote |
You can escape any other character, but a warning will be issued at the highest warning level.
The second way to delimit a string uses the single-quote ("'") character, which does not do any variable expansion or backslash processing (except for "\\" and "\'" so you can insert backslashes and single-quotes in a singly-quoted string).
When a string is evaluated as a numeric value, the resulting value and type are determined as follows.
The string will evaluate as a double if it contains any of the characters '.', 'e', or 'E'. Otherwise, it will evaluate as an integer.
The value is given by the initial portion of the string. If the string starts with valid numeric data, this will be the value used. Otherwise, the value will be 0 (zero). Valid numeric data is an optional sign, followed by one or more digits (optionally containing a decimal point), followed by an optional exponent. The exponent is an 'e' or 'E' followed by one or more digits.
When the first expression is a string, the type of the variable will depend on the second expression.
$foo = 1 + "10.5"; // $foo is double (11.5)
$foo = 1 + "-1.3e3"; // $foo is double (-1299)
$foo = 1 + "bob-1.3e3"; // $foo is integer (1)
$foo = 1 + "bob3"; // $foo is integer (1)
$foo = 1 + "10 Small Pigs"; // $foo is integer (11)
$foo = 1 + "10 Little Piggies"; // $foo is integer (11)
$foo = "10.0 pigs " + 1; // $foo is integer (11)
$foo = "10.0 pigs " + 1.0; // $foo is double (11)
For more information on this conversion, see the Unix manual page for strtod(3).
Arrays actually act like both hash tables (associative arrays) and indexed arrays (vectors).
PHP supports both scalar and associative arrays. In fact, there is no difference between the two. You can create an array using the list() or array() functions, or you can explicitly set each array element value.
$a[0] = "abc";
$a[1] = "def";
$b["foo"] = 13;
You can also create an array by simply adding values to the array.
$a[] = "hello"; // $a[2] == "hello"
$a[] = "world"; // $a[3] == "world"
Arrays may be sorted using the asort(), arsort(), ksort(), rsort(), sort(), uasort(), usort(), and uksort() functions depending on the type of sort you want.
You can count the number of items in an array using the count() function.
You can traverse an array using next() and prev() functions. Another common way to traverse an array is to use the each() function.
Multi-dimensional arrays are actually pretty simple. For each dimension of the array, you add another [key] value to the end:
$a[1] = $f; # one dimensional examples
$a["foo"] = $f;
$a[1][0] = $f; # two dimensional
$a["foo"][2] = $f; # (you can mix numeric and associative indices)
$a[3]["bar"] = $f; # (you can mix numeric and associative indices)
$a["foo"][4]["bar"][0] = $f; # four dimensional!
You can "fill up" multi-dimensional arrays in many ways, but the trickiest one to understand is how to use the array() command for associative arrays. These two snippets of code fill up the one-dimensional array in the same way:
# Example 1:
$a["color"] = "red";
$a["taste"] = "sweet";
$a["shape"] = "round";
$a["name"] = "apple";
$a[3] = 4;
# Example 2:
$a = array(
"color" => "red",
"taste" => "sweet",
"shape" => "round",
"name" => "apple",
3 => 4
);
The array() function can be nested for multi-dimensional arrays:
<?
$a = array(
"apple" => array(
"color" => "red",
"taste" => "sweet",
"shape" => "round"
),
"orange" => array(
"color" => "orange",
"taste" => "sweet",
"shape" => "round"
),
"banana" => array(
"color" => "yellow",
"taste" => "paste-y",
"shape" => "banana-shaped"
)
);
echo $a["apple"]["taste"]; # will output "sweet"
?>
To initialize an object, you use the new statement to instantiate the object to a variable.
class foo {
function do_foo () {
echo "Doing foo.";
}
}
$bar = new foo;
$bar -> do_foo ();
PHP does not require (or support) explicit type definition in variable declaration; a variable's type is determined by the context in which that variable is used. That is to say, if you assign a string value to variable var, var becomes a string. If you then assign an integer value to var, it becomes an integer.
An example of PHP's automatic type conversion is the addition operator '+'. If any of the operands is a double, then all operands are evaluated as doubles, and the result will be a double. Otherwise, the operands will be interpreted as integers, and the result will also be an integer. Note that this does NOT change the types of the operands themselves; the only change is in how the operands are evaluated.
$foo = "0"; // $foo is string (ASCII 48)
$foo++; // $foo is the string "1" (ASCII 49)
$foo += 1; // $foo is now an integer (2)
$foo = $foo + 1.3; // $foo is now a double (3.3)
$foo = 5 + "10 Little Piggies"; // $foo is integer (15)
$foo = 5 + "10 Small Pigs"; // $foo is integer (15)
If the last two examples above seem odd, see String conversion.
If you wish to force a variable to be evaluated as a certain type, see the section on Type casting. If you wish to change the type of a variable, see settype().
Type casting in PHP works much as it does in C: the name of the desired type is written in parentheses before the variable which is to be cast.
$foo = 10; // $foo is an integer
$bar = (double) $foo; // $bar is a double
The casts allowed are:
(int), (integer) - cast to integer
(real), (double), (float) - cast to double
(string) - cast to string
(array) - cast to array
(object) - cast to object
Note that tabs and spaces are allowed inside the parentheses, so the following are functionally equivalent:
$foo = (int) $bar;
$foo = ( int ) $bar;
The scope of a variable is the context within which it is defined. For the most part all PHP variables only have a single scope. However, within user-defined functions a local function scope is introduced. Any variable used inside a function is by default limited to the local function scope. For example:
$a = 1; /* global scope */
Function Test () {
echo $a; /* reference to local scope variable */
}
Test ();
This script will not produce any output because the echo statement refers to a local version of the $a variable, and it has not been assigned a value within this scope. You may notice that this is a little bit different from the C language in that global variables in C are automatically available to functions unless specifically overridden by a local definition. This can cause some problems in that people may inadvertently change a global variable. In PHP global variables must be declared global inside a function if they are going to be used in that function. An example:
$a = 1;
$b = 2;
Function Sum () {
global $a, $b;
$b = $a + $b;
}
Sum ();
echo $b;
The above script will output "3". By declaring $a and $b global within the function, all references to either variable will refer to the global version. There is no limit to the number of global variables that can be manipulated by a function.
A second way to access variables from the global scope is to use the special PHP-defined $GLOBALS array. The previous example can be rewritten as:
$a = 1;
$b = 2;
Function Sum () {
$GLOBALS["b"] = $GLOBALS["a"] + $GLOBALS["b"];
}
Sum ();
echo $b;
The $GLOBALS array is an associative array with the name of the global variable being the key and the contents of that variable being the value of the array element.
Another important feature of variable scoping is the static variable. A static variable exists only in a local function scope, but it does not lose its value when program execution leaves this scope. Consider the following example:
Function Test () {
$a = 0;
echo $a;
$a++;
}
This function is quite useless since every time it is called it sets $a to 0 and prints "0". The $a++ which increments the variable serves no purpose since as soon as the function exits the $a variable disappears. To make a useful counting function which will not lose track of the current count, the $a variable is declared static:
Function Test () {
static $a = 0;
echo $a;
$a++;
}
Now, every time the Test() function is called it will print the value of $a and increment it.
Static variables are also essential when functions are called recursively. A recursive function is one which calls itself. Care must be taken when writing a recursive function because it is possible to make it recurse indefinitely. You must make sure you have an adequate way of terminating the recursion. The following simple function recursively counts to 10:
Function Test () {
static $count = 0;
$count++;
echo $count;
if ($count < 10) {
Test ();
}
$count--;
}
Sometimes it is convenient to be able to have variable variable names. That is, a variable name which can be set and used dynamically. A normal variable is set with a statement such as:
$a = "hello";
A variable variable takes the value of a variable and treats that as the name of a variable. In the above example, hello, can be used as the name of a variable by using two dollar signs. ie.
$$a = "world";
At this point two variables have been defined and stored in the PHP symbol tree: $a with contents "hello" and $hello with contents "world". Therefore, this statement:
echo "$a ${$a}";
produces the exact same output as:
echo "$a $hello";
ie. they both produce: hello world.
In order to use variable variables with arrays, you have to resolve an ambiguity problem. That is, if you write $$a[1] then the parser needs to know if you meant to use $a[1] as a variable, or if you wanted $$a as the variable and then the [1] index from that variable. The syntax for resolving this ambiguity is: ${$a[1]} for the first case and ${$a}[1] for the second.
When a form is submitted to a PHP script, any variables from that form will be automatically made available to the script by PHP. For instance, consider the following form:
Example 7-1. Simple form variable <form action="foo.php3" method="post">
Name: <input type="text" name="name"><br>
<input type="submit">
</form>
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When submitted, PHP will create the variable $name, which will will contain whatever what entered into the Name: field on the form.
PHP also understands arrays in the context of form variables, but only in one dimension. You may, for example, group related variables together, or use this feature to retrieve values from a multiple select input:
Example 7-2. More complex form variables <form action="array.php" method="post">
Name: <input type="text" name="personal[name]"><br>
Email: <input type="text" name="personal[email]"><br>
Beer: <br>
<select multiple name="beer[]">
<option value="warthog">Warthog
<option value="guinness">Guinness
</select>
<input type="submit">
</form>
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If PHP's track_vars feature is turned on, either by the track_vars configuration setting or the <?php_track_vars?> directive, then variables submitted via the POST or GET methods will also be found in the global associative arrays $HTTP_POST_VARS and $HTTP_GET_VARS as appropriate.
When submitting a form, it is possible to use an image instead of the standard submit button with a tag like:
<input type=image src="image.gif" name="sub">
When the user clicks somewhere on the image, the accompanying form will be transmitted to the server with two additional variables, sub_x and sub_y. These contain the coordinates of the user click within the image. The experienced may note that the actual variable names sent by the browser contains a period rather than an underscore, but PHP converts the period to an underscore automatically.
PHP transparently supports HTTP cookies as defined by Netscape's Spec. Cookies are a mechanism for storing data in the remote browser and thus tracking or identifying return users. You can set cookies using the SetCookie() function. Cookies are part of the HTTP header, so the SetCookie function must be called before any output is sent to the browser. This is the same restriction as for the Header() function. Any cookies sent to you from the client will automatically be turned into a PHP variable just like GET and POST method data.
If you wish to assign multiple values to a single cookie, just add [] to the cookie name. For example:
SetCookie ("MyCookie[]", "Testing", time()+3600);
Note that a cookie will replace a previous cookie by the same name in your browser unless the path or domain is different. So, for a shopping cart application you may want to keep a counter and pass this along. i.e.
Example 7-3. SetCookie Example $Count++;
SetCookie ("Count", $Count, time()+3600);
SetCookie ("Cart[$Count]", $item, time()+3600);
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PHP automatically makes environment variables available as normal PHP variables.
echo $HOME; /* Shows the HOME environment variable, if set. */
Since information coming in via GET, POST and Cookie mechanisms also automatically create PHP variables, it is sometimes best to explicitly read a variable from the environment in order to make sure that you are getting the right version. The getenv() function can be used for this. You can also set an environment variable with the putenv() function.
Because PHP determines the types of variables and converts them (generally) as needed, it is not always obvious what type a given variable is at any one time. PHP includes several functions which find out what type a variable is. They are gettype(), is_long(), is_double(), is_string(), is_array(), and is_object().
PHP defines several constants and provides a mechanism for defining more at run-time. Constants are much like variables, save for the two facts that constants must be defined using the define() function, and that they cannot later be redefined to another value.
The predefined constants (always available) are:
The name of the script file presently being parsed. If used within a file which has been included or required, then the name of the included file is given, and not the name of the parent file.
The number of the line within the current script file which is being parsed. If used within a file which has been included or required, then the position within the included file is given.
The string representation of the version of the PHP parser presently in use; e.g. '3.0.8-dev'.
The name of the operating system on which the PHP parser is executing; e.g. 'Linux'.
A true value.
A false value.
Denotes an error other than a parsing error from which recovery is not possible.
Denotes a condition where PHP knows something is wrong, but will continue anyway; these can be caught by the script itself. An example would be an invalid regexp in ereg().
The parser choked on invalid syntax in the script file. Recovery is not possible.
Something happened which may or may not be an error. Execution continues. Examples include using an unquoted string as a hash index, or accessing a variable which has not been set.
The E_* constants are typically used with the error_reporting() function for setting the error reporting level.
You can define additional constants using the define() function.
Note that these are constants, not C-style macros; only valid scalar data may be represented by a constant.
Example 8-1. Defining Constants <?php
define("CONSTANT", "Hello world.");
echo CONSTANT; // outputs "Hello world."
?>
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Example 8-2. Using __FILE__ and __LINE__ <?php
function report_error($file, $line, $message) {
echo "An error occured in $file on line $line: $message.";
}
report_error(__FILE__,__LINE__, "Something went wrong!");
?>
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Expressions are the most important building stones of PHP. In PHP, almost anything you write is an expression. The simplest yet most accurate way to define an expression is "anything that has a value".
The most basic forms of expressions are constants and variables. When you type "$a = 5", you're assigning '5' into $a. '5', obviously, has the value 5, or in other words '5' is an expression with the value of 5 (in this case, '5' is an integer constant).
After this assignment, you'd expect $a's value to be 5 as well, so if you wrote $b = $a, you'd expect it to behave just as if you wrote $b = 5. In other words, $a is an expression with the value of 5 as well. If everything works right, this is exactly what will happen.
Slightly more complex examples for expressions are functions. For instance, consider the following function:
function foo () {
return 5;
}
Assuming you're familiar with the concept of functions (if you're not, take a look at the chapter about functions), you'd assume that typing $c = foo() is essentially just like writing $c = 5, and you're right. Functions are expressions with the value of their return value. Since foo() returns 5, the value of the expression 'foo()' is 5. Usually functions don't just return a static value but compute something.
Of course, values in PHP don't have to be integers, and very often they aren't. PHP supports three scalar value types: integer values, floating point values and string values (scalar values are values that you can't 'break' into smaller pieces, unlike arrays, for instance). PHP also supports two composite (non-scalar) types: arrays and objects. Each of these value types can be assigned into variables or returned from functions.
So far, users of PHP/FI 2 shouldn't feel any change. However, PHP takes expressions much further, in the same way many other languages do. PHP is an expression-oriented language, in the sense that almost everything is an expression. Consider the example we've already dealt with, '$a = 5'. It's easy to see that there are two values involved here, the value of the integer constant '5', and the value of $a which is being updated to 5 as well. But the truth is that there's one additional value involved here, and that's the value of the assignment itself. The assignment itself evaluates to the assigned value, in this case 5. In practice, it means that '$a = 5', regardless of what it does, is an expression with the value 5. Thus, writing something like '$b = ($a = 5)' is like writing '$a = 5; $b = 5;' (a semicolon marks the end of a statement). Since assignments are parsed in a right to left order, you can also write '$b = $a = 5'.
Another good example of expression orientation is pre- and post-increment and decrement. Users of PHP/FI 2 and many other languages may be familiar with the notation of variable++ and variable--. These are increment and decrement operators. In PHP/FI 2, the statement '$a++' has no value (is not an expression), and thus you can't assign it or use it in any way. PHP enhances the increment/decrement capabilities by making these expressions as well, like in C. In PHP, like in C, there are two types of increment - pre-increment and post-increment. Both pre-increment and post-increment essentially increment the variable, and the effect on the variable is idential. The difference is with the value of the increment expression. Pre-increment, which is written '++$variable', evaluates to the incremented value (PHP increments the variable before reading its value, thus the name 'pre-increment'). Post-increment, which is written '$variable++' evaluates to the original value of $variable, before it was incremented (PHP increments the variable after reading its value, thus the name 'post-increment').
A very common type of expressions are comparison expressions. These expressions evaluate to either 0 or 1, meaning FALSE or TRUE (respectively). PHP supports > (bigger than), >= (bigger than or equal to), == (equal), != (not equal), < (smaller than) and <= (smaller than or equal to). These expressions are most commonly used inside conditional execution, such as if statements.
The last example of expressions we'll deal with here is combined operator-assignment expressions. You already know that if you want to increment $a by 1, you can simply write '$a++' or '++$a'. But what if you want to add more than one to it, for instance 3? You could write '$a++' multiple times, but this is obviously not a very efficient or comfortable way. A much more common practice is to write '$a = $a + 3'. '$a + 3' evaluates to the value of $a plus 3, and is assigned back into $a, which results in incrementing $a by 3. In PHP, as in several other languages like C, you can write this in a shorter way, which with time would become clearer and quicker to understand as well. Adding 3 to the current value of $a can be written '$a += 3'. This means exactly "take the value of $a, add 3 to it, and assign it back into $a". In addition to being shorter and clearer, this also results in faster execution. The value of '$a += 3', like the value of a regular assignment, is the assigned value. Notice that it is NOT 3, but the combined value of $a plus 3 (this is the value that's assigned into $a). Any two-place operator can be used in this operator-assignment mode, for example '$a -= 5' (subtract 5 from the value of $a), '$b *= 7' (multiply the value of $b by 7), etc.
There is one more expression that may seem odd if you haven't seen it in other languages, the ternary conditional operator:
$first ? $second : $third
The following example should help you understand pre- and post-increment and expressions in general a bit better:
function double($i) {
return $i*2;
}
$b = $a = 5; /* assign the value five into the variable $a and $b */
$c = $a++; /* post-increment, assign original value of $a
(5) to $c */
$e = $d = ++$b; /* pre-increment, assign the incremented value of
$b (6) to $d and $e */
/* at this point, both $d and $e are equal to 6 */
$f = double($d++); /* assign twice the value of $d before
the increment, 2*6 = 12 to $f */
$g = double(++$e); /* assign twice the value of $e after
the increment, 2*7 = 14 to $g */
$h = $g += 10; /* first, $g is incremented by 10 and ends with the
value of 24. the value of the assignment (24) is
then assigned into $h, and $h ends with the value
of 24 as well. */In the beginning of the chapter we said that we'll be describing the various statement types, and as promised, expressions can be statements. However, not every expression is a statement. In this case, a statement has the form of 'expr' ';' that is, an expression followed by a semicolon. In '$b=$a=5;', $a=5 is a valid expression, but it's not a statement by itself. '$b=$a=5;' however is a valid statement.
One last thing worth mentioning is the truth value of expressions. In many events, mainly in conditional execution and loops, you're not interested in the specific value of the expression, but only care about whether it means TRUE or FALSE (PHP doesn't have a dedicated boolean type). The truth value of expressions in PHP is calculated in a similar way to perl. Any numeric non-zero numeric value is TRUE, zero is FALSE. Be sure to note that negative values are non-zero and are thus considered TRUE! The empty string and the string "0" are FALSE; all other strings are TRUE. With non-scalar values (arrays and objects) - if the value contains no elements it's considered FALSE, otherwise it's considered TRUE.
PHP provides a full and powerful implementation of expressions, and documenting it entirely goes beyond the scope of this manual. The above examples should give you a good idea about what expressions are and how you can construct useful expressions. Throughout the rest of this manual we'll write expr to indicate any valid PHP expression.
Remember basic arithmetic from school? These work just like those.
Table 10-1. Arithmetic Operators
| example | name | result |
|---|---|---|
| $a + $b | Addition | Sum of $a and $b. |
| $a - $b | Subtraction | Remainder of $b subtracted from $a. |
| $a * $b | Multiplication | Product of $a and $b. |
| $a / $b | Division | Dividend of $a and $b. |
| $a % $b | Modulus | Remainder of $a divided by $b. |
There is only really one string operator -- the concatenation operator (".").
$a = "Hello ";
$b = $a . "World!"; // now $b = "Hello World!"
The basic assignment operator is "=". Your first inclination might be to think of this as "equal to". Don't. It really means that the the left operand gets set to the value of the expression on the rights (that is, "gets set to").
The value of an assignment expression is the value assigned. That is, the value of "$a = 3" is 3. This allows you to do some tricky things:
$a = ($b = 4) + 5; // $a is equal to 9 now, and $b has been set to 4.
In addition to the basic assignment operator, there are "combined operators" for all of the binary arithmetic and string operators that allow you to use a value in an expression and then set its value to the result of that expression. For example:
$a = 3; $a += 5; // sets $a to 8, as if we had said: $a = $a + 5; $b = "Hello "; $b .= "There!"; // sets $b to "Hello There!", just like $b = $b . "There!";
Bitwise operators allow you to turn specific bits within an integer on or off.
Table 10-2. Bitwise Operators
| example | name | result |
|---|---|---|
| $a & $b | And | Bits that are set in both $a and $b are set. |
| $a | $b | Or | Bits that are set in either $a or $b are set. |
| $a ^ $b | Xor | Bits that are set in $a or $b but not both are set. |
| ~ $a | Not | Bits that are set in $a are not set, and vice versa. |
| $a << $b | Shift left | Shift the bits of $a $b steps to the left (each step means "multiply by two") |
| $a >> $b | Shift right | Shift the bits of $a $b steps to the right (each step means "divide by two") |
Table 10-3. Logical Operators
| example | name | result |
|---|---|---|
| $a and $b | And | True of both $a and $b are true. |
| $a or $b | Or | True if either $a or $b is true. |
| $a xor $b | Or | True if either $a or $b is true, but not both. |
| ! $a | Not | True if $a is not true. |
| $a && $b | And | True of both $a and $b are true. |
| $a || $b | Or | True if either $a or $b is true. |
The reason for the two different variations of "and" and "or" operators is that they operate at different precedences. (See below.)
Comparison operators, as their name imply, allow you to compare two values.
Table 10-4. Comparson Operators
| example | name | result |
|---|---|---|
| $a == $b | Equal | True if $a is equal to $b. |
| $a != $b | Not equal | True if $a is not equal to $b. |
| $a < $b | Less than | True if $a is strictly less than $b. |
| $a > $b | Greater than | True if $a is strictly greater than $b. |
| $a <= $b | Less than or equal to | True if $a is less than or equal to $b. |
| $a >= $b | Greater than or equal to | True if $a is greater than or equal to $b. |
Another conditional operator is the "?:" (or trinary) operator, which operates as in C and many other languages.
(expr1) ? (expr2) : (expr3);
The precedence of an operator specifies how "tightly" it binds two expressions together. For example, in the expression 1 + 5 * 3, the answer is 16 and not 18 because the multiplication ("*") operator has a higher precedence than the addition ("+") operator.
The following table lists the precedence of operators with the lowest-precedence operators listed first.
Table 10-5. Operator Precedence
| Associativity | Operators |
|---|---|
| left | , |
| left | or |
| left | xor |
| left | and |
| right | |
| left | = += -= *= /= .= %= &= != ~= <<= >>= |
| left | ? : |
| left | || |
| left | && |
| left | | |
| left | ^ |
| left | & |
| non-associative | == != |
| non-associative | < <= > >= |
| left | << >> |
| left | + - . |
| left | * / % |
| right | ! ~ ++ -- (int) (double) (string) (array) (object) @ |
| right | [ |
| non-associative | new |
Any PHP script is built out of a series of statements. A statement can be an assignment, a function call, a loop, a conditional statement of even a statement that does nothing (an empty statement). Statements usually end with a semicolon. In addition, statements can be grouped into a statement-group by encapsulating a group of statements with curly braces. A statement-group is a statement by itself as well. The various statement types are described in this chapter.
The if construct is one of the most important features of many languages, PHP included. It allows for conditional execution of code fragments. PHP features an if structure that is similar to that of C:
if (expr)
statement
As described in the section about expressions, expr is evaluated to its truth value. If expr evaluates to TRUE, PHP will execute statement, and if it evaluates to FALSE - it'll ignore it.
The following example would display a is bigger than b if $a is bigger than $b:
if ($a > $b)
print "a is bigger than b";
Often you'd want to have more than one statement to be executed conditionally. Of course, there's no need to wrap each statement with an if clause. Instead, you can group several statements into a statement group. For example, this code would display a is bigger than b if $a is bigger than $b, and would then assign the value of $a into $b:
if ($a > $b) {
print "a is bigger than b";
$b = $a;
}
If statements can be nested indefinitely within other if statements, which provides you with complete flexibility for conditional execution of the various parts of your program.
Often you'd want to execute a statement if a certain condition is met, and a different statement if the condition is not met. This is what else is for. else extends an if statement to execute a statement in case the expression in the if statement evaluates to FALSE. For example, the following code would display a is bigger than b if $a is bigger than $b, and a is NOT bigger than b otherwise:
if ($a > $b) {
print "a is bigger than b";
} else {
print "a is NOT bigger than b";
}
elseif, as its name suggests, is a combination of if and else. Like else, it extends an if statement to execute a different statement in case the original if expression evaluates to FALSE. However, unlike else, it will execute that alternative expression only if the elseif conditional expression evaluates to TRUE. For example, the following code would display a is bigger than b, a equal to b or a is smaller than b:
if ($a > $b) {
print "a is bigger than b";
} elseif ($a == $b) {
print "a is equal to b";
} else {
print "a is smaller than b";
}
There may be several elseifs within the same if statement. The first elseif expression (if any) that evaluates to true would be executed. In PHP, you can also write 'else if' (in two words) and the behavior would be identical to the one of 'elseif' (in a single word). The syntactic meaning is slightly different (if you're familiar with C, this is the same behavior) but the bottom line is that both would result in exactly the same behavior.
The elseif statement is only executed if the preceding if expression and any preceding elseif expressions evaluated to FALSE, and the current elseif expression evaluated to TRUE.
PHP offers a different way to group statements within an if statement. This is most commonly used when you nest HTML blocks inside if statements, but can be used anywhere. Instead of using curly braces, if (expr) should be followed by a colon, the list of one or more statements, and end with endif;. Consider the following example:
<?php if ($a==5): ?>
A = 5
<?php endif; ?>
In the above example, the HTML block "A = 5" is nested within an if statement written in the alternative syntax. The HTML block would be displayed only if $a is equal to 5.
The alternative syntax applies to else and elseif as well. The following is an if structure with elseif and else in the alternative format:
if ($a == 5):
print "a equals 5";
print "...";
elseif ($a == 6):
print "a equals 6";
print "!!!";
else:
print "a is neither 5 nor 6";
endif;
while loops are the simplest type of loop in PHP. They behave just like their C counterparts. The basic form of a while statement is:
while (expr) statement
The meaning of a while statement is simple. It tells PHP to execute the nested statement(s) repeatedly, as long as the while expression evaluates to TRUE. The value of the expression is checked each time at the beginning of the loop, so even if this value changes during the execution of the nested statement(s), execution will not stop until the end of the iteration (each time PHP runs the statements in the loop is one iteration). Sometimes, if the while expression evaluates to FALSE from the very beginning, the nested statement(s) won't even be run once.
Like with the if statement, you can group multiple statements within the same while loop by surrounding a group of statements with curly braces, or by using the alternate syntax:
while (expr): statement ... endwhile;
The following examples are identical, and both print numbers from 1 to 10:
/* example 1 */
$i = 1;
while ($i <= 10) {
print $i++; /* the printed value would be
$i before the increment
(post-increment) */
}
/* example 2 */
$i = 1;
while ($i <= 10):
print $i;
$i++;
endwhile;
do..while loops are very similar to while loops, except the truth expression is checked at the end of each iteration instead of in the beginning. The main difference from regular while loops is that the first iteration of a do..while loop is guarenteed to run (the truth expression is only checked at the end of the iteration), whereas it's may not necessarily run with a regular while loop (the truth expression is checked at the beginning of each iteration, if it evaluates to FALSE right from the beginning, the loop execution would end immediately).
There is just one syntax for do..while loops:
$i = 0;
do {
print $i;
} while ($i>0);
The above loop would run one time exactly, since after the first iteration, when truth expression is checked, it evaluates to FALSE ($i is not bigger than 0) and the loop execution ends.
Advanced C users may be familiar with a different usage of the do..while loop, to allow stopping execution in the middle of code blocks, by encapsulating them with do..while(0), and using the break statement. The following code fragment demonstrates this:
do {
if ($i < 5) {
print "i is not big enough";
break;
}
$i *= $factor;
if ($i < $minimum_limit) {
break;
}
print "i is ok";
...process i...
} while(0);
Don't worry if you don't understand this right away or at all. You can code scripts and even powerful scripts without using this `feature'.
for loops are the most complex loops in PHP. They behave like their C counterparts. The syntax of a for loop is:
for (expr1; expr2; expr3) statement
The first expression (expr1) is evaluated (executed) once unconditionally at the beginning of the loop.
In the beginning of each iteration, expr2 is evaluated. If it evaluates to TRUE, the loop continues and the nested statement(s) are executed. If it evaluates to FALSE, the execution of the loop ends.
At the end of each iteration, expr3 is evaluated (executed).
Each of the expressions can be empty. expr2 being empty means the loop should be run indefinitely (PHP implicitly considers it as TRUE, like C). This may not be as useless as you might think, since often you'd want to end the loop using a conditional break statement instead of using the for truth expression.
Consider the following examples. All of them display numbers from 1 to 10:
/* example 1 */
for ($i = 1; $i <= 10; $i++) {
print $i;
}
/* example 2 */
for ($i = 1;;$i++) {
if ($i > 10) {
break;
}
print $i;
}
/* example 3 */
$i = 1;
for (;;) {
if ($i > 10) {
break;
}
print $i;
$i++;
}
/* example 4 */
for ($i = 1; $i <= 10; print $i, $i++) ;
Of course, the first example appears to be the nicest one (or perhaps the fourth), but you may find that being able to use empty expressions in for loops comes in handy in many occasions.
PHP also supports the alternate "colon syntax" for for loops.
for (expr1; expr2; expr3): statement; ...; endfor;
Other languages have a foreach statement to traverse an array or hash. PHP uses the while statement and the list() and each() functions for this. See the documentation for these functions for an example.
break breaks out of the current looping control-structures.
$i = 0;
while ($i < 10) {
if ($arr[$i] == "stop") {
break;
}
$i++;
}
continue is used within looping structures to skip the rest of the current loop iteration and continue execution at the beginning of the next iteration.
while (list($key,$value) = each($arr)) {
if ($key % 2) { // skip even members
continue;
}
do_something_odd ($value);
}
The switch statement is similar to a series of IF statements on the same expression. In many occasions, you may want to compare the same variable (or expression) with many different values, and execute a different piece of code depending on which value it equals to. This is exactly what the switch statement is for.
The following two examples are two different ways to write the same thing, one using a series of if statements, and the other using the switch statement:
if ($i == 0) {
print "i equals 0";
}
if ($i == 1) {
print "i equals 1";
}
if ($i == 2) {
print "i equals 2";
}
switch ($i) {
case 0:
print "i equals 0";
break;
case 1:
print "i equals 1";
break;
case 2:
print "i equals 2";
break;
}
It is important to understand how the switch statement is executed in order to avoid mistakes. The switch statement executes line by line (actually, statement by statement). In the beginning, no code is executed. Only when a case statement is found with a value that matches the value of the switch expression does PHP begin to execute the statements. PHP continues to execute the statements until the end of the switch block, or the first time it sees a break statement. If you don't write a break statement at the end of a case's statement list, PHP will go on executing the statements of the following case. For example:
switch ($i) {
case 0:
print "i equals 0";
case 1:
print "i equals 1";
case 2:
print "i equals 2";
}
Here, if $i equals to 0, PHP would execute all of the print statements! If $i equals to 1, PHP would execute the last two print statements, and only if $i equals to 2, you'd get the 'expected' behavior and only 'i equals 2' would be displayed. So, it's important not to forget break statements (even though you may want to avoid supplying them on purpose under certain circumstances).
The statement list for a case can also be empty, which simply passes control into the statement list for the next case.
switch ($i) {
case 0:
case 1:
case 2:
print "i is less than 3 but not negative";
break;
case 3:
print "i is 3";
}
A special case is the default case. This case matches anything that wasn't matched by the other cases. For example:
switch ($i) {
case 0:
print "i equals 0";
break;
case 1:
print "i equals 1";
break;
case 2:
print "i equals 2";
break;
default:
print "i is not equal to 0, 1 or 2";
}
The case expression may be any expression that evaluates to a scalar type, that is, integer or floating-point numbers and strings. Arrays or objects are meaningless in that context.
The require statement replaces itself with the specified file, much like the C preprocessor's #include works.
This means that you can't put a require statement inside of a loop structure and expect it to include the contents of a different file on each iteration. To do that, use an include statement.
require 'header.inc';
The include statement includes and evaluates the specified file.
This happens each time the include statement is encountered, so you can use an include statement within a looping structure to include a number of different file.
$files = array ('first.inc', 'second.inc', 'third.inc');
for ($i = 0; $i < count($files); $i++) {
include $files[$i];
}
include differs from require in that the include statement is re-evaluated each time it is encountered (and only when it is being executed), whereas the require statement is replaced by the required file when it is first encountered, whether the contents of the file will be evaluated or not (for example, if it is inside an if statement whose condition evaluated to false).
Because include is a special language construct, you must enclose it within a statement block if it is inside a conditional block.
/* This is WRONG and will not work as desired. */
if ($condition)
include($file);
else
include($other);
/* This is CORRECT. */
if ($condition) {
include($file);
} else {
include($other);
}
When the file is evaluated, the parser begins in "HTML-mode" which will output the contents of the file until the first PHP start tag (<?) is encountered.
See also readfile(), require(), virtual().
A function may be defined using syntax such as the following:
function foo ($arg_1, $arg_2, ..., $arg_n) {
echo "Example function.\n";
return $retval;
}
Any valid PHP code may appear inside a function, even other functions and class definitions.
Functions must be defined before they are referenced.
Values are returned by using the optional return statement. Any type may be returned, including lists and objects.
function square ($num) {
return $num * $num;
}
echo square (4); // outputs '16'.
You can't return multiple values from a function, but similar results can be obtained by returning a list.
function small_numbers() {
return array (0, 1, 2);
}
list ($zero, $one, $two) = small_numbers();
Information may be passed to functions via the argument list, which is a comma-delimited list of variables and/or constants.
PHP supports passing arguments by value (the default), passing by reference, and default argument values. Variable-length argument lists are not supported, but a similar effect may be obtained by passing arrays.
function takes_array($input) {
echo "$input[0] + $input[1] = ", $input[0]+$input[1];
}
By default, function arguments are passed by value (so that if you change the value of the argument within the function, it does not get changed outside of the function). If you wish to allow a function to modify its arguments, you must pass them by reference.
If you want an argument to a function to always be passed by reference, you can prepend an ampersand (&) to the argument name in the function definition:
function add_some_extra(&$string) {
$string .= 'and something extra.';
}
$str = 'This is a string, ';
add_some_extra($str);
echo $str; // outputs 'This is a string, and something extra.'
If you wish to pass a variable by reference to a function which does not do this by default, you may prepend an ampersand to the argument name in the function call:
function foo ($bar) {
$bar .= ' and something extra.';
}
$str = 'This is a string, ';
foo ($str);
echo $str; // outputs 'This is a string, '
foo (&$str);
echo $str; // outputs 'This is a string, and something extra.'
A function may define C++-style default values for scalar arguments as follows:
function makecoffee ($type = "cappucino") {
return "Making a cup of $type.\n";
}
echo makecoffee ();
echo makecoffee ("espresso");
The output from the above snippet is:
Making a cup of cappucino.
Making a cup of espresso.
The default value must be a constant expression, not (for example) a variable or class member.
In PHP 4.0 it's also possible to specify unset for default argument. This means that the argument will not be set at all, if a value is not supplied.
Note that when using default arguments, any defaults should be on the right side of any non-default arguments; otherwise, things will not work as expected. Consider the following code snippet:
function makeyogurt ($type = "acidophilus", $flavour) {
return "Making a bowl of $type $flavour.\n";
}
echo makeyogurt ("raspberry"); // won't work as expected
The output of the above example is:
Warning: Missing argument 2 in call to makeyogurt() in
/usr/local/etc/httpd/htdocs/php3test/functest.html on line 41
Making a bowl of raspberry .
Now, compare the above with this:
function makeyogurt ($flavour, $type = "acidophilus") {
return "Making a bowl of $type $flavour.\n";
}
echo makeyogurt ("raspberry"); // works as expected
The output of this example is:
Making a bowl of acidophilus raspberry.
The old_function statement allows you to declare a function using a syntax identical to PHP/FI2 (except you must replace 'function' with 'old_function'.
This is a deprecated feature, and should only be used by the PHP/FI2->PHP3 convertor.
| Warning |
Functions declared as old_function cannot be called from PHP's internal code. Among other things, this means you can't use them in functions such as usort(), array_walk(), and register_shutdown_function(). You can get around this limitation by writing a wrapper function (in normal PHP3 form) to call the old_function. |
A class is a collection of variables and functions working with these variables. A class is defined using the following syntax:
<?php
class Cart {
var $items; // Items in our shopping cart
// Add $num articles of $artnr to the cart
function add_item ($artnr, $num) {
$this->items[$artnr] += $num;
}
// Take $num articles of $artnr out of the cart
function remove_item ($artnr, $num) {
if ($this->items[$artnr] > $num) {
$this->items[$artnr] -= $num;
return true;
} else {
return false;
}
}
}
?>
This defines a class named Cart that consists of an associative array of articles in the cart and two functions to add and remove items from this cart.
Classes are types, that is, they are blueprints for actual variables. You have to create a variables of the desired type with the new operator.
$cart = new Cart;
$cart->add_item("10", 1);
This creates an object $cart of the class Cart. The function add_item() of that object is being called to add 1 item of article number 10 to the cart.
Classes can be extensions of other classes. The extended or derived class has all variables and functions of the base class and what you add in the extended definition. This is done using the extends keyword.
class Named_Cart extends Cart {
var $owner;
function set_owner ($name) {
$this->owner = $name;
}
}
This defines a class Named_Cart that has all variables and functions of Cart plus an additional variable $owner and an additional function set_owner(). You create a named cart the usual way and can now set and get the carts owner. You can still use normal cart functions on named carts:
$ncart = new Named_Cart; // Create a named cart
$ncart->set_owner ("kris"); // Name that cart
print $ncart->owner; // print the cart owners name
$ncart->add_item ("10", 1); // (inherited functionality from cart)
Within functions of a class the variable $this means this object. You have to use $this->something to access any variable or function named something within your current object.
Constructors are functions in a class that are automatically called when you create a new instance of a class. A function becomes a constructor when it has the same name as the class.
class Auto_Cart extends Cart {
function Auto_Cart () {
$this->add_item ("10", 1);
}
}
This defines a class Auto_Cart that is a Cart plus a constructor which initializes the cart with one item of article number "10" each time a new Auto_Cart is being made with "new". Constructors can also take arguments and these arguments can be optional, which makes them much more useful.
class Constructor_Cart {
function Constructor_Cart ($item = "10", $num = 1) {
$this->add_item ($item, $num);
}
}
// Shop the same old boring stuff.
$default_cart = new Constructor_Cart;
// Shop for real...
$different_cart = new Constructor_Cart ("20", 17);
| Caution |
For derived classes, the constructor of the parent class is not automatically called when the derived class's constructor is called. |
There are 4 types of errors and warnings in PHP. They are:
1 - Normal Function Errors
2 - Normal Warnings
4 - Parser Errors
8 - Notices (warnings you can ignore but which may imply a bug in your code)
The above 4 numbers are added up to define an error reporting level. The default error reporting level is 7 which is 1 + 2 + 4, or everything except notices. This level can be changed in the php3.ini file with the error_reporting directive. It can also be set in your Apache httpd.conf file with the php3_error_reporting directive or lastly it may be set at runtime within a script using the error_reporting() function.
All PHP expressions can also be called with the "@" prefix, which turns off error reporting for that particular expression. If an error occurred during such an expression and the track_errors feature is enabled, you can find the error message in the global variable $php_errormsg.
PHP is not limited to creating just HTML output. It can also be used to create GIF image files, or even more convenient GIF image streams. You will need to compile PHP with the GD library of image functions for this to work.
Example 15-1. GIF creation with PHP <?php
Header("Content-type: image/gif");
$string=implode($argv," ");
$im = imagecreatefromgif("images/button1.gif");
$orange = ImageColorAllocate($im, 220, 210, 60);
$px = (imagesx($im)-7.5*strlen($string))/2;
ImageString($im,3,$px,9,$string,$orange);
ImageGif($im);
ImageDestroy($im);
?>
|
The HTTP Authentication hooks in PHP are only available when it is running as an Apache module and is hence not available in the CGI version. In an Apache module PHP script, it is possible to use the Header() function to send an "Authentication Required" message to the client browser causing it to pop up a Username/Password input window. Once the user has filled in a username and a password, the URL containing the PHP script will be called again with the variables, $PHP_AUTH_USER, $PHP_AUTH_PW and $PHP_AUTH_TYPE set to the user name, password and authentication type respectively. Only "Basic" authentication is supported at this point. See the Header() function for more information.
An example script fragment which would force client authentication on a page would be the following:
Example 16-1. HTTP Authentication example <?php
if(!isset($PHP_AUTH_USER)) {
Header("WWW-Authenticate: Basic realm=\"My Realm\"");
Header("HTTP/1.0 401 Unauthorized");
echo "Text to send if user hits Cancel button\n";
exit;
} else {
echo "Hello $PHP_AUTH_USER.<P>";
echo "You entered $PHP_AUTH_PW as your password.<P>";
}
?>
|
Instead of simply printing out the $PHP_AUTH_USER and $PHP_AUTH_PW, you would probably want to check the username and password for validity. Perhaps by sending a query to a database, or by looking up the user in a dbm file.
Watch out for buggy Internet Explorer browsers out there. They seem very picky about the order of the headers. Sending the WWW-Authenticate header before the HTTP/1.0 401 header seems to do the trick for now.
In order to prevent someone from writing a script which reveals the password for a page that was authenticated through a traditional external mechanism, the PHP_AUTH variables will not be set if external authentication is enabled for that particular page. In this case, the $REMOTE_USER variable can be used to identify the externally-authenticated user.
Note, however, that the above does not prevent someone who controls a non-authenticated URL from stealing passwords from authenticated URLs on the same server.
Both Netscape and Internet Explorer will clear the local browser window's authentication cache for the realm upon receiving a server response of 401. This can effectively "log out" a user, forcing them to re-enter their username and password. Some people use this to "time out" logins, or provide a "log-out" button.
Example 16-2. HTTP Authentication example forcing a new name/password <?php
function authenticate() {
Header( "WWW-authenticate: basic realm='Test Authentication System'");
Header( "HTTP/1.0 401 Unauthorized");
echo "You must enter a valid login ID and password to access this resource\n";
exit;
}
if(!isset($PHP_AUTH_USER) || ($SeenBefore == 1 && !strcmp($OldAuth, $PHP_AUTH_USER)) ) {
authenticate();
}
else {
echo "Welcome: $PHP_AUTH_USER<BR>";
echo "Old: $OldAuth";
echo "<FORM ACTION=\"$PHP_SELF\" METHOD=POST>\n";
echo "<INPUT TYPE=HIDDEN NAME=\"SeenBefore\" VALUE=\"1\">\n";
echo "<INPUT TYPE=HIDDEN NAME=\"OldAuth\" VALUE=\"$PHP_AUTH_USER\">\n";
echo "<INPUT TYPE=Submit VALUE=\"Re Authenticate\">\n";
echo "</FORM>\n";
}
?>
|
This behavior is not required by the HTTP Basic authentication standard, so you should never depend on this. Testing with Lynx has shown that Lynx does not clear the authentication credentials with a 401 server response, so pressing back and then forward again will open the resource (as long as the credential requirements haven't changed).
Also note that this does not work using Microsoft's IIS server and the CGI version of PHP due to a limitation of IIS.
PHP transparently supports HTTP cookies. Cookies are a mechanism for storing data in the remote browser and thus tracking or identifying return users. You can set cookies using the setcookie() function. Cookies are part of the HTTP header, so setcookie() must be called before any output is sent to the browser. This is the same limitation that header() has.
Any cookies sent to you from the client will automatically be turned into a PHP variable just like GET and POST method data. If you wish to assign multiple values to a single cookie, just add [] to the cookie name. For more details see the setcookie() function.
PHP is capable of receiving file uploads from any RFC-1867 compliant browser (which includes Netscape Navigator 3 or later, Microsoft Internet Explorer 3 with a patch from Microsoft, or later without a patch). This feature lets people upload both text and binary files. With PHP's authentication and file manipulation functions, you have full control over who is allowed to upload and what is to be done with the file once it has been uploaded.
Note that PHP also supports PUT-method file uploads as used by Netscape Composer and W3C's Amaya clients. See the PUT Method Support for more details.
A file upload screen can be built by creating a special form which looks something like this:
Example 18-1. File Upload Form <FORM ENCTYPE="multipart/form-data" ACTION="_URL_" METHOD=POST>
<INPUT TYPE="hidden" name="MAX_FILE_SIZE" value="1000">
Send this file: <INPUT NAME="userfile" TYPE="file">
<INPUT TYPE="submit" VALUE="Send File">
</FORM>
|
$userfile - The temporary filename in which the uploaded file was stored on the server machine.
$userfile_name - The original name of the file on the sender's system.
$userfile_size - The size of the uploaded file in bytes.
$userfile_type - The mime type of the file if the browser provided this information. An example would be "image/gif".
Files will by default be stored in the server's default temporary directory. This can be changed by setting the environment variable TMPDIR in the environment in which PHP runs. Setting it using putenv() from within a PHP script will not work.
The PHP script which receives the uploaded file should implement whatever logic is necessary for determining what should be done with the uploaded file. You can for example use the $file_size variable to throw away any files that are either too small or too big. You could use the $file_type variable to throw away any files that didn't match a certain type criteria. Whatever the logic, you should either delete the file from the temporary directory or move it elsewhere.
The file will be deleted from the temporary directory at the end of the request if it has not been moved away or renamed.
The MAX_FILE_SIZE item cannot specify a file size greater than the file size that has been set in the upload_max_filesize in the PHP3.ini file or the corresponding php3_upload_max_filesize Apache .conf directive. The default is 2 Megabytes.
Please note that the CERN httpd seems to strip off everything starting at the first whitespace in the content-type mime header it gets from the client. As long as this is the case, CERN httpd will not support the file upload feature.
It is possible to upload multiple files simultaneously and have the information organized automatically in arrays for you. To do so, you need to use the same array submission syntax in the HTML form as you do with multiple selects and checkboxes:
Note: Support for multiple file uploads was added in version 3.0.10.
Example 18-2. Uploading multiple forms <form action="file-upload.html" method="post" enctype="multipart/form-data">
Send these files:<br>
<input name="userfile[]" type="file"><br>
<input name="userfile[]" type="file"><br>
<input type="submit" value="Send files">
</form>
|
When the above form is submitted, the arrays $userfile, $userfile_name, and $userfile_size will be formed in the global scope (as well as in $HTTP_POST_VARS). Each of these will be a numerically indexed array of the appropriate values for the submitted files.
For instance, assume that the filenames /home/test/review.html and /home/test/xwp.out are submitted. In this case, $userfile_name[0] would contain the value review.html, and $userfile_name[1] would contain the value xwp.out. Similarly, $userfile_size[0] would contain review.html's filesize, and so forth.
PHP provides support for the HTTP PUT method used by clients such as Netscape Composer and W3C Amaya. PUT requests are much simpler than a file upload and they look something like this:
PUT /path/filename.html HTTP/1.1
This would normally mean that the remote client would like to save the content that follows as: /path/filename.html in your web tree. It is obviously not a good idea for Apache or PHP to automatically let everybody overwrite any files in your web tree. So, to handle such a request you have to first tell your web server that you want a certain PHP script to handle the request. In Apache you do this with the Script directive. It can be placed almost anywhere in your Apache configuration file. A common place is inside a <Directory> block or perhaps inside a <Virtualhost> block. A line like this would do the trick:
Script PUT /put.php3
This tells Apache to send all PUT requests for URIs that match the context in which you put this line to the put.php3 script. This assumes, of course, that you have PHP enabled for the .php3 extension and PHP is active.
Inside your put.php3 file you would then do something like this:
<? copy($PHP_UPLOADED_FILE_NAME,$DOCUMENT_ROOT.$REQUEST_URI); ?>
This would copy the file to the location requested by the remote client. You would probably want to perform some checks and/or authenticate the user before performing this file copy. The only trick here is that when PHP sees a PUT-method request it stores the uploaded file in a temporary file just like those handled bu the POST-method. When the request ends, this temporary file is deleted. So, your PUT handling PHP script has to copy that file somewhere. The filename of this temporary file is in the $PHP_PUT_FILENAME variable, and you can see the suggested destination filename in the $REQUEST_URI (may vary on non-Apache web servers). This destination filename is the one that the remote client specified. You do not have to listen to this client. You could, for example, copy all uploaded files to a special uploads directory.
As long as support for the "URL fopen wrapper" is enabled when you configure PHP (which it is unless you explicitly pass the --disable-url-fopen-wrapper flag to configure), you can use HTTP and FTP URLs with most functions that take a filename as a parameter, including the require() and include() statements.
For example, you can use this to open a file on a remote web server, parse the output for the data you want, and then use that data in a database query, or simply to output it in a style matching the rest of your website.
Example 19-1. Getting the title of a remote page <?php
$file = fopen("http://www.php.net/", "r");
if (!$file) {
echo "<p>Unable to open remote file.\n";
exit;
}
while (!feof($file)) {
$line = fgets($file, 1024);
/* This only works if the title and its tags are on one line. */
if (eregi("<title>(.*)</title>", $line, $out)) {
$title = $out[1];
break;
}
}
fclose($file);
?>
|
You can also write to files on an FTP as long you connect as a user with the correct access rights, and the file doesn't exist already. To connect as a user other than 'anonymous', you need to specify the username (and possibly password) within the URL, such as 'ftp://user:password@ftp.example.com/path/to/file'. (You can use the same sort of syntax to access files via HTTP when they require Basic authentication.)
Example 19-2. Storing data on a remote server <?php
$file = fopen("ftp://ftp.php.net/incoming/outputfile", "w");
if (!$file) {
echo "<p>Unable to open remote file for writing.\n";
exit;
}
/* Write the data here. */
fputs($file, "$HTTP_USER_AGENT\n");
fclose($file);
?>
|
Note: You might get the idea from the example above to use this technique to write to a remote log, but as mentioned above, you can only write to a new file using the URL fopen() wrappers. To do distributed logging like that, you should take a look at syslog().
Note: The following applies to 3.0.7 and later.
Internally in PHP a connection status is maintained. There are 3 possible states:
0 - NORMAL
1 - ABORTED
2 - TIMEOUT
When a PHP script is running normally the NORMAL state, is active. If the remote client disconnects the ABORTED state flag is turned on. A remote client disconnect is usually caused by the user hitting his STOP button. If the PHP-imposed time limit (see set_time_limit()) is hit, the TIMEOUT state flag is turned on.
You can decide whether or not you want a client disconnect to cause your script to be aborted. Sometimes it is handy to always have your scripts run to completion even if there is no remote browser receiving the output. The default behaviour is however for your script to be aborted when the remote client disconnects. This behaviour can be set via the ignore_user_abort php3.ini directive as well as through the corresponding php3_ignore_user_abort Apache .conf directive or with the ignore_user_abort() function. If you do not tell PHP to ignore a user abort and the user aborts, your script will terminate. The one exception is if you have registered a shutdown function using register_shutdown_function(). With a shutdown function, when the remote user hits his STOP button, the next time your script tries to output something PHP will detect that the connection has been aborted and the shutdown function is called. This shutdown function will also get called at the end of your script terminating normally, so to do something different in case of a client diconnect you can use the connection_aborted() function. This function will return true if the connection was aborted.
Your script can also be terminated by the built-in script timer. The default timeout is 30 seconds. It can be changed using the max_execution_time php3.ini directive or the corresponding php3_max_execution_time Apache .conf directive as well as with the set_time_limit() function. When the timer expires the script will be aborted and as with the above client disconnect case, if a shutdown function has been registered it will be called. Within this shutdown function you can check to see if a timeout caused the shutdown function to be called by calling the connection_timeout() function. This function will return true if a timeout caused the shutdown function to be called.
One thing to note is that both the ABORTED and the TIMEOUT states can be active at the same time. This is possible if you tell PHP to ignore user aborts. PHP will still note the fact that a user may have broken the connection, but the script will keep running. If it then hits the time limit it will be aborted and your shutdown function, if any, will be called. At this point you will find that connection_timeout() and connection_aborted() return true. You can also check both states in a single call by using the connection_status(). This function returns a bitfield of the active states. So, if both states are active it would return 3, for example.
Persistent connections are SQL links that do not close when the execution of your script ends. When a persistent connection is requested, PHP checks if there's already an identical persistent connection (that remained open from earlier) - and if it exists, it uses it. If it does not exist, it creates the link. An 'identical' connection is a connection that was opened to the same host, with the same username and the same password (where applicable).
People who aren't thoroughly familiar with the way web servers work and distribute the load may mistake persistent connects for what they're not. In particular, they do not give you an ability to open 'user sessions' on the same SQL link, they do not give you an ability to build up a transaction efficently, and they don't do a whole lot of other things. In fact, to be extremely clear about the subject, persistent connections don't give you any functionality that wasn't possible with their non-persistent brothers.
Why?
This has to do with the way web servers work. There are three ways in which your web server can utilize PHP to generate web pages.
The first method is to use PHP as a CGI "wrapper". When run this way, an instance of the PHP interpreter is created and destroyed for every page request (for a PHP page) to your web server. Because it is destroyed after every request, any resources that it acquires (such as a link to an SQL database server) are closed when it is destroyed. In this case, you do not gain anything from trying to use persistent connections -- they simply don't persist.
The second, and most popular, method is to run PHP as a module in a multiprocess web server, which currently only includes Apache. A multiprocess server typically has one process (the parent) which coordinates a set of processes (its children) who actually do the work of serving up web pages. When each request comes in from a a client, it is handed off to one of the children that is not already serving another client. This means that when the same client makes a second request to the server, it may be serviced by a different child process than the first time. What a persistent connection does for you in this case it make it so each child process only needs to connect to your SQL server the first time that it serves a page that makes us of such a connection. When another page then requires a connection to the SQL server, it can reuse the connection that child established earlier.
The last method is to use PHP as a plug-in for a multithreaded web server. Currently this is only theoretical -- PHP does not yet work as a plug-in for any multithreaded web servers. Work is progressing on support for ISAPI, WSAPI, and NSAPI (on Windows), which will all allow PHP to be used as a plug-in on multithreaded servers like Netscape FastTrack, Microsoft's Internet Information Server (IIS), and O'Reilly's WebSite Pro. When this happens, the behavior will be essentially the same as for the multiprocess model described before.
If persistent connections don't have any added functionality, what are they good for?
The answer here is extremely simple -- efficiency. Persistent connections are good if the overhead to create a link to your SQL server is high. Whether or not this overhead is really high depends on many factors. Like, what kind of database it is, whether or not it sits on the same computer on which your web server sits, how loaded the machine the SQL server sits on is and so forth. The bottom line is that if that connection overhead is high, persistent connections help you considerably. They cause the child process to simply connect only once for its entire lifespan, instead of every time it processes a page that requires connecting to the SQL server. This means that for every child that opened a persistent connection will have its own open persistent connection to the server. For example, if you had 20 different child processes that ran a script that made a persistent connection to your SQL server, you'd have 20 different connections to the SQL server, one from each child.
An important summary. Persistent connections were designed to have one-to-one mapping to regular connections. That means that you should always be able to replace persistent connections with non-persistent connections, and it won't change the way your script behaves. It may (and probably will) change the efficiency of the script, but not its behavior!
The Adabas D functions are deprecated, you probably want to use the Unified ODBC functions instead.
class apache_lookup_uri(string filename);This performs a partial request for a URI. It goes just far enough to obtain all the important information about the given resource and returns this information in a class. The properties of the returned class are:
| status |
| the_request |
| status_line |
| method |
| content_type |
| handler |
| uri |
| filename |
| path_info |
| args |
| boundary |
| no_cache |
| no_local_copy |
| allowed |
| send_bodyct |
| bytes_sent |
| byterange |
| clength |
| unparsed_uri |
| mtime |
| request_time |
Note: Note: apache_lookup_uri only works when PHP is installed as an Apache module
string apache_note(string note_name, string [note_value]);apache_note() is an Apache-specific function which gets and sets values in a request's notes table. If called with one argument, it returns the current value of note note_name. If called with two arguments, it sets the value of note note_name to note_value and returns the previous value of note note_name.
array getallheaders(void);This function returns an associative array of all the HTTP headers in the current request.
Note: You can also get at the value of the common CGI variables by reading them from the environment, which works whether or not you are using PHP as an Apache module. Use phpinfo() to see a list of all of the environment variables defined this way.
Example 1. getallheaders() Example $headers = getallheaders();
while (list($header, $value) = each($headers)) {
echo "$header: $value<br>\n";
} |
Note: getallheaders() is currently only supported when PHP runs as an Apache module.
int virtual(string filename);virtual() is an Apache-specific function which is equivalent to <!--#include virtual...--> in mod_include. It performs an Apache sub-request. It is useful for including CGI scripts or .shtml files, or anything else that you would parse through Apache. Note that for a CGI script, the script must generate valid CGI headers. At the minimum that means it must generate a Content-type header. For PHP files, you should use include() or require().
array array(...);Returns an array of the parameters. The parameters can be given an index with the => operator.
Note: array() is a language construct used to represent literal arrays, and not a regular function.
The following example demonstrates how to create a two-dimensional array, how to specify keys for associative arrays, and how to skip-and-continue numeric indices in normal arrays.
Example 1. array() example $fruits = array(
"fruits" => array("a"=>"orange","b"=>"banana","c"=>"apple"),
"numbers" => array(1, 2, 3, 4, 5, 6),
"holes" => array("first", 5 => "second", "third")
); |
See also: list().
int array_push(array array, mixed var, [...]);array_push() treats array as a stack, and pushes the passed variables onto the end of array. The length of array increases by the number of variables pushed. Has the same effect as:
$array[] = $var;
repeated for each var.
Returns the new number of elements in the array.
Example 1. array_push() example $stack = array(1, 2);
array_push($stack, "+", 3);
|
See also array_pop(), array_shift(), and array_unshift().
Note: This function was added in PHP 4.0.
mixed array_pop(array array);array_pop() pops and returns the last value of the array, shortening the array by one element.
Example 1. array_pop() example $stack = array("orange", "apple", "raspberry");
$fruit = array_pop($stack);
After this, $stack has only 2 elements: "orange" and "apple", and $fruit has "raspberry". |
See also array_push(), array_shift(), and array_unshift().
Note: This function was added in PHP 4.0.
int array_unshift(array array, mixed var, [...]);
array_unshift() prepends passed elements to the front of the array. Note that the list of elements is prepended as a whole, so that the prepended elements stay in the same order.
Returns the new number of elements in the array.
Example 1. array_unshift() example $queue = array("p1", "p3");
array_unshift($queue, "p4", "p5", "p6");
|
See also array_shift(), array_push(), and array_pop().
Note: This function was added in PHP 4.0.
mixed array_shift(array array);array_shift() shifts the first value of the array off and returns it, shortening the array by one element and moving everything down.
Example 1. array_shift() example $args = array("-v", "-f");
$opt = array_shift($args);
|
See also array_unshift(), array_push(), and array_pop().
Note: This function was added in PHP 4.0.
array array_slice(array array, int offset, int
[length]
);array_slice() returns a sequence of elements from the array specified by the offset and length parameters.
If offset is positive, the sequence will start at that offset in the array. If offset is negative, the sequence will start that far from the end of the array.
If length is given and is positive, then the sequence will have that many elements in it. If length is given and is negative then the sequence will stop that many elements from the end of the array. If it is omitted, then the sequence will have everything from offset up until the end of the array.
Example 1. array_slice() examples $input = array("a", "b", "c", "d", "e");
$output = array_slice($input, 2); // returns "c", "d", and "e"
$output = array_slice($input, 2, -1); // returns "c", "d"
$output = array_slice($input, -2, 1); // returns "d"
$output = array_slice($input, 0, 3); // returns "a", "b", and "c"
|
See also array_splice().
Note: This function was added in PHP 4.0.
array array_splice(array input, int offset, int
[length]
, array
[replacement]);array_splice() removed the elements designated by offset and length from the input array, and replaces them with the elements of the replacement array, if supplied.
If offset is positive then the start of removed portion is at that offset from the beginning of the input array. If offset is negative then it starts that far from the end of the input array.
If length is omitted, removes everything from offset to the end of the array. If length is specified and is positive, then that many elements will be removed. If length is specified and is negative then the end of the removed portion will be that many elements from the end of the array. Tip: to remove everything from offset to the end of the array when replacement is also specified, use count($input) for length.
If replacement array is specified, then the removed elements are replaced with elements from this array. If offset and length are such that nothing is removed, then the elements from the replacement array are inserted in the place specified by the offset. Tip: if the replacement is just one element it is not necessary to put array() around it, unless the element is an array itself.
The following equivalences hold:
array_push($input, $x, $y) array_splice($input, count($input), 0, array($x, $y))
array_pop($input) array_splice($input, -1)
array_shift($input) array_splice($input, 0, 1)
array_unshift($input, $x, $y) array_splice($input, 0, 0, array($x, $y))
$a[$x] = $y array_splice($input, $x, 1, $y)
Returns the array consisting of removed elements.
Example 1. array_splice() examples $input = array("red", "green", "blue", "yellow");
array_splice($input, 2); // $input is now array("red", "green")
array_splice($input, 1, -1); // $input is now array("red", "yellow")
array_splice($input, 1, count($input), "orange"); // $input is now array("red", "orange")
array_splice($input, -1, 1, array("black", "maroon")); // $input is now array("red", "green", "blue", "black", "maroon")
|
See also array_slice().
Note: This function was added in PHP 4.0.
array array_merge(array array1, array array2, [ ...]
);array_merge() merges the elements of two or more arrays together so that the values of one are appended to the end of the previous one. It returns the resulting array.
If the input arrays had the same string keys, then the later value for that key will overwrite previous one. If, however, the arrays have the same numeric key, this does not happen since the values are appended.
Example 1. array_merge() example $array1 = array("color" => "red", 2, 4);
$array2 = array("a", "b", "color" => "green", "shape" => "trapezoid");
array_merge($array1, $array2);
Resulting array will be array("color" => "green", 2, 4, "a", "b", "shape" => "trapezoid"). |
Note: This function was added in PHP 4.0.
array array_keys(array input);array_keys() returns all the keys, numeric and string, from the input array.
Example 1. array_keys() example $array = array(0 => 100, "color" => "red");
array_keys($array); // returns array(0, "color")
|
See also array_values().
Note: This function was added in PHP 4.0.
array array_values(array input);array_values() returns all the values from the input array.
Example 1. array_values() example $array = array("size" => "XL", "color" => "gold");
array_values($array); // returns array("XL", "gold")
|
Note: This function was added in PHP 4.0.
int array_walk(array arr, string func, mixed userdata);Applies the function named by func to each element of arr. func will be passed array value as the first parameter and array key as the second parameter. If userdata is supplied, it will be passed as the third parameter to the user function. If func requires more than two or three arguments, depending on userdata, a warning will be generated each time array_walk() calls func. These warnings may be suppressed by prepending the '@' sign to the array_walk() call, or by using error_reporting().
Note: If func needs to be working with the actual values of the array, specify that the first parameter of func should be passed by reference. Then any changes made to those elements will be made in the array itself.
Example 1. array_walk() example $fruits = array("d"=>"lemon","a"=>"orange","b"=>"banana","c"=>"apple");
function test_alter( &$item1, $key, $prefix ) {
$item1 = "$prefix: $item1";
}
function test_print( $item2, $key ) {
echo "$key. $item2<br>\n";
}
array_walk( $fruits, 'test_print' );
array_walk( $fruits, 'test_alter', 'fruit' );
array_walk( $fruits, 'test_print' );
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void arsort(array array);This function sorts an array such that array indices maintain their correlation with the array elements they are associated with. This is used mainly when sorting associative arrays where the actual element order is significant.
Example 1. arsort() example $fruits = array("d"=>"lemon","a"=>"orange","b"=>"banana","c"=>"apple");
arsort($fruits);
for(reset($fruits); $key = key($fruits); next($fruits)) {
echo "fruits[$key] = ".$fruits[$key]."\n";
} |
void asort(array array);This function sorts an array such that array indices maintain their correlation with the array elements they are associated with. This is used mainly when sorting associative arrays where the actual element order is significant.
Example 1. asort() example $fruits = array("d"=>"lemon","a"=>"orange","b"=>"banana","c"=>"apple");
asort($fruits);
for(reset($fruits); $key = key($fruits); next($fruits)) {
echo "fruits[$key] = ".$fruits[$key]."\n";
} |
array compact(string varname | array
varnames, [...]);compact() takes a variable number of parameters. Each parameter can be either a string containing the name of the variable, or an array of variable names. The array can contain other arrays of variable names inside it; compact() handles it recursively.
For each of these, compact() looks for a variable with that name in the current symbol table and adds it to the output array such that the variable name becomes the key and the contents of the variable become the value for that key. In short, it does the opposite of extract(). It returns the output array with all the variables added to it.
Example 1. compact() example $city = "San Francisco";
$state = "CA";
$event = "SIGGRAPH";
$location_vars = array("city", "state");
$result = compact("event", $location_vars);
After this, $result will be array("event" => "SIGGRAPH", "city" => "San Francisco", "state" => "CA"). |
See also extract().
Note: This function was added in PHP 4.0.
int count(mixed var);Returns the number of elements in var, which is typically an array (since anything else will have one element).
Returns 1 if the variable is not an array.
Returns 0 if the variable is not set.
| Warning |
count() may return 0 for a variable that isn't set, but it may also return 0 for a variable that has been initialized with an empty array. Use isset() to test if a variable is set. |
See also: sizeof(), isset(), and is_array().
mixed current(array array);Every array has an internal pointer to its "current" element, which is initialized to the first element inserted into the array.
The current() function simply returns the array element that's currently being pointed by the internal pointer. It does not move the pointer in any way. If the internal pointer points beyond the end of the elements list, current() returns false.
| Warning |
If the array contains empty elements (0 or "", the empty string) then this function will return false for these elements as well. This makes it impossible to determine if you are really at the end of the list in such an array using current(). To properly traverse an array that may contain empty elements, use the each() function. |
array each(array array);Returns the current key and value pair from the array array and advances the array cursor. This pair is returned in a four-element array, with the keys 0, 1, key, and value. Elements 0 and key contain the key name of the array element, and 1 and value contain the data.
If the internal pointer for the array points past the end of the array contents, each() returns false.
Example 1. each() examples $foo = array( "bob", "fred", "jussi", "jouni" );
$bar = each( $foo );
$bar now contains the following key/value pairs:
$foo = array( "Robert" => "Bob", "Seppo" => "Sepi" );
$bar = each( $foo );
$bar now contains the following key/value pairs:
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each() is typically used in conjunction with list() to traverse an array; for instance, $HTTP_POST_VARS:
Example 2. Traversing $HTTP_POST_VARS with each() echo "Values submitted via POST method:<br>";
while (list($key, $val) = each($HTTP_POST_VARS)) {
echo "$key => $val<br>";
}
|
After each() has executed, the array cursor will be left on the next element of the array, or on the last element if it hits the end of the array.
See also key(), list(), current(), reset(), next(), and prev().
void extract(array var_array, int [extract_type], string [prefix]);This function is used to import variables from an array into the current symbol table. It takes associative array var_array and treats keys as variable names and values as variable values. For each key/value pair it will create a variable in the current symbol table, subject to extract_type and prefix parameters.
extract() checks for colissions with existing variables. The way collisions are treated is determined by extract_type. It can be one of the following values:
If there is a collision, overwrite the existing variable.
If there is a collision, don't overwrite the existing variable.
If there is a collision, prefix the new variable with prefix.
Prefix all variables with prefix.
If extract_type is not specified, it is assumed to be EXTR_OVERWRITE.
Note that prefix is only required if extract_type is EXTR_PREFIX_SAME or EXTR_PREFIX_ALL.
extract() checks each key to see if it constitues a valid variable name, and if it does only then does it proceed to import it.
A possible use for extract is to import into symbol table variables contained in an associative array returned by wddx_deserialize().
Example 1. extract example <?
/* Suppose that $var_array is an array returned from
wddx_deserialize */
$size = "large";
$var_array = array("color" => "blue",
"size" => "medium",
"shape" => "sphere");
extract($var_array, EXTR_PREFIX_SAME, "wddx");
print "$color, $size, $shape, $wddx_size\n";
?>
|
The above example will produce:
blue, large, sphere, medium
The $size wasn't overwritten, becaus we specified EXTR_PREFIX_SAME, which resulted in $wddx_size being created. If EXTR_SKIP was specified, then $wddx_size wouldn't even have been created. EXTR_OVERWRITE would have cause $size to have value "medium", and EXTR_PREFIX_ALL would result in new variables being named $wddx_color, $wddx_size, and $wddx_shape.
bool in_array(mixed needle, array haystack);Searches haystack for needle and returns true if it is found in the array, false otherwise.
Example 1. in_array() example $os = array("Mac", "NT", "Irix", "Linux");
if (in_array("Irix", $os))
print "Got Irix";
|
Note: This function was added in PHP 4.0.
int ksort(array array);Sorts an array by key, maintaining key to data correlations. This is useful mainly for associative arrays.
Example 1. ksort() example $fruits = array("d"=>"lemon","a"=>"orange","b"=>"banana","c"=>"apple");
ksort($fruits);
for(reset($fruits); $key = key($fruits); next($fruits)) {
echo "fruits[$key] = ".$fruits[$key]."\n";
} |
void list(...);Like array(), this is not really a function, but a language construct. list() is used to assign a list of variables in one operation.
Example 1. list() example <table>
<tr>
<th>Employee name</th>
<th>Salary</th>
</tr>
<?php
$result = mysql($conn, "SELECT id, name, salary FROM employees");
while (list($id, $name, $salary) = mysql_fetch_row($result)) {
print(" <tr>\n".
" <td><a href=\"info.php3?id=$id\">$name</a></td>\n".
" <td>$salary</td>\n".
" </tr>\n");
}
?></table> |
mixed next(array array);Returns the array element in the next place that's pointed by the internal array pointer, or false if there are no more elements.
next() behaves like current(), with one difference. It advances the internal array pointer one place forward before returning the element. That means it returns the next array element and advances the internal array pointer by one. If advancing the internal array pointer results in going beyond the end of the element list, next() returns false.
| Warning |
If the array contains empty elements then this function will return false for these elements as well. To properly traverse an array which may contain empty elements see the each() function. |
mixed prev(array array);Returns the array element in the previous place that's pointed by the internal array pointer, or false if there are no more elements.
| Warning |
If the array contains empty elements then this function will return false for these elements as well. To properly traverse an array which may contain empty elements see the each() function. |
prev() behaves just like next(), except it rewinds the internal array pointer one place instead of advancing it.
array range(int low, int high);range() returns an array of integers from low to high, inclusive.
See shuffle() for an example of its use.
mixed reset(array array);reset() rewinds array's internal pointer to the first element.
reset() returns the value of the first array element.
void rsort(array array);This function sorts an array in reverse order (highest to lowest).
Example 1. rsort() example $fruits = array("lemon","orange","banana","apple");
rsort($fruits);
for (reset($fruits); list($key,$value) = each($fruits); ) {
echo "fruits[$key] = ", $value, "\n";
}
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void shuffle(array array);This function shuffles (randomizes the order of the elements in) an array.
Example 1. shuffle() example $numbers = range(1,20);
srand(time());
shuffle($numbers);
while (list(,$number) = each($numbers)) {
echo "$number ";
} |
See also arsort(), asort(), ksort(), rsort(), sort() and usort().
void sort(array array);This function sorts an array. Elements will be arranged from lowest to highest when this function has completed.
Example 1. sort() example $fruits = array("lemon","orange","banana","apple");
sort($fruits);
for(reset($fruits); $key = key($fruits); next($fruits)) {
echo "fruits[$key] = ".$fruits[$key]."\n";
} |
void uasort(array array, function cmp_function);This function sorts an array such that array indices maintain their correlation with the array elements they are associated with. This is used mainly when sorting associative arrays where the actual element order is significant. The comparison function is user-defined.
void uksort(array array, function cmp_function);This function will sort the keys of an array using a user-supplied comparison function. If the array you wish to sort needs to be sorted by some non-trivial criteria, you should use this function.
Example 1. uksort() example function mycompare($a, $b) {
if ($a == $b) return 0;
return ($a > $b) ? -1 : 1;
}
$a = array(4 => "four", 3 => "three", 20 => "twenty", 10 => "ten");
uksort($a, mycompare);
while(list($key, $value) = each($a)) {
echo "$key: $value\n";
} |
See also arsort(), asort(), uasort(), ksort(), rsort() and sort().
void usort(array array, function cmp_function);This function will sort an array by its values using a user-supplied comparison function. If the array you wish to sort needs to be sorted by some non-trivial criteria, you should use this function.
The comparison function must return an integer less than, equal to, or greater than zero if the first argument is considered to be respectively less than, equal to, or greater than the second. If two members compare as equal, their order in the sorted array is undefined.
Example 1. usort() example function cmp($a,$b) {
if ($a == $b) return 0;
return ($a > $b) ? -1 : 1;
}
$a = array(3,2,5,6,1);
usort($a, cmp);
while(list($key,$value) = each($a)) {
echo "$key: $value\n";
} |
Note: Obviously in this trivial case the rsort() function would be more appropriate.
| Warning |
The underlying quicksort function in some C libraries (such as on Solaris systems) may cause PHP to crash if the comparison function does not return consistent values. |
The aspell() functions allows you to check the spelling on a word and offer suggestions.
You need the aspell library, available from: http://metalab.unc.edu/kevina/aspell/
int aspell_new(string master, string personal);aspell_new() opens up a new dictionary and returns the dictionary link identifier for use in other aspell functions.
Example 1. aspell_new $aspell_link=aspell_new("english");
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boolean aspell_check(int dictionary_link, string word);aspell_check() checks the spelling of a word and returns true if the spelling is correct, false if not.
Example 1. aspell_check $aspell_link=aspell_new("english");
if (aspell_check($aspell_link,"testt")) {
echo "This is a valid spelling";
} else {
echo "Sorry, wrong spelling";
}
|
boolean aspell_check_raw(int dictionary_link, string word);aspell_check_raw() checks the spelling of a word, without changing its case or trying to trim it in any way and returns true if the spelling is correct, false if not.
Example 1. aspell_check_raw $aspell_link=aspell_new("english");
if (aspell_check_raw($aspell_link,"testt")) {
echo "This is a valid spelling";
} else {
echo "Sorry, wrong spelling";
}
|
array aspell_suggest(int dictionary_link, string word);aspell_suggest() returns an array of possible spellings for the given word.
Example 1. aspell_suggest $aspell_link=aspell_new("english");
if (!aspell_check($aspell_link,"testt")) {
$suggestions=aspell_suggest($aspell_link,"testt");
for($i=0; $i < count($suggestions); $i++) {
echo "Possible spelling: " . $suggestions[$i] . "<br>";
}
}
|
string bcadd(string left operand, string right operand, int [scale]);Adds the left operand to the right operand and returns the sum in a string. The optional scale parameter is used to set the number of digits after the decimal place in the result.
See also bcsub().
int bccomp(string left operand, string right operand, int [scale]);Compares the left operand to the right operand and returns the result as an integer. The optional scale parameter is used to set the number of digits after the decimal place which will be used in the comparion. The return value is 0 if the two operands are equal. If the left operand is larger than the right operand the return value is +1 and if the left operand is less than the right operand the return value is -1.
string bcdiv(string left operand, string right operand, int [scale]);Divides the left operand by the right operand and returns the result. The optional scale sets the number of digits after the decimal place in the result.
See also bcmul().
string bcmod(string left operand, string modulus);Get the modulus of the left operand using modulus.
See also bcdiv().
string bcmul(string left operand, string right operand, int [scale]);Multiply the left operand by the right operand and returns the result. The optional scale sets the number of digits after the decimal place in the result.
See also bcdiv().
string bcpow(string x, string y, int [scale]);Raise x to the power y. The scale can be used to set the number of digits after the decimal place in the result.
See also bcsqrt().
string bcscale(int scale);This function sets the default scale parameter for all subsequent bc math functions that do not explicitly specify a scale parameter.
string bcsqrt(string operand, int scale);Return the square root of the operand. The optional scale parameter sets the number of digits after the decimal place in the result.
See also bcpow().
string bcsub(string left operand, string right operand, int [scale]);Subtracts the right operand from the left operand and returns the result in a string. The optional scale parameter is used to set the number of digits after the decimal place in the result.
See also bcadd().
The calendar functions are only available if you have compiled the calendar extension in dl/calendar. Read dl/README for instructions on using it.
The calendar extension presents a series of functions to simplify converting between different calendar formats. The intermediary or standard it is based on is the Julian Day Count. The Julian Day Count is a count of days starting way earlier than any date most people would need to track (somewhere around 4000bc). To convert between calendar systems, you must first convert to Julian Day Count, then to the calendar system of your choice. Julian Day Count is very different from the Julian Calendar! For more information on calendar systems visit http://genealogy.org/~scottlee/cal-overview.html. Excerpts from this page are included in these instructions, and are in quotes.
string jdtogregorian(int julianday);Converts Julian Day Count to a string containing the Gregorian date in the format of "month/day/year"
int gregoriantojd(int month, int day, int year);Valid Range for Gregorian Calendar 4714 B.C. to 9999 A.D.
Although this software can handle dates all the way back to 4714 B.C., such use may not be meaningful. The Gregorian calendar was not instituted until October 15, 1582 (or October 5, 1582 in the Julian calendar). Some countries did not accept it until much later. For example, Britain converted in 1752, The USSR in 1918 and Greece in 1923. Most European countries used the Julian calendar prior to the Gregorian.
Example 1. Calendar functions <?php
$jd = GregorianToJD(10,11,1970);
echo("$jd\n");
$gregorian = JDToGregorian($jd);
echo("$gregorian\n");
?> |
string jdtojulian(int julianday);Converts Julian Day Count to a string containing the Julian Calendar Date in the format of "month/day/year".
int juliantojd(int month, int day, int year);Valid Range for Julian Calendar 4713 B.C. to 9999 A.D.
Although this software can handle dates all the way back to 4713 B.C., such use may not be meaningful. The calendar was created in 46 B.C., but the details did not stabilize until at least 8 A.D., and perhaps as late at the 4th century. Also, the beginning of a year varied from one culture to another - not all accepted January as the first month.
int jewishtojd(int month, int day, int year);Valid Range Although this software can handle dates all the way back to the year 1 (3761 B.C.), such use may not be meaningful.
The Jewish calendar has been in use for several thousand years, but in the early days there was no formula to determine the start of a month. A new month was started when the new moon was first observed.
string jdtofrench(int month, int day, int year);Converts a Julian Day Count to the French Republican Calendar.
int frenchtojd(int month, int day, int year);Converts a date from the French Republican Calendar to a Julian Day Count
These routines only convert dates in years 1 through 14 (Gregorian dates 22 September 1792 through 22 September 1806). This more than covers the period when the calendar was in use.
string jdmonthname(int julianday, int mode);Returns a string containing a month name. mode tells this function which calendar to convert the Julian Day Count to, and what type of month names are to be returned.
Table 1. Calendar modes
| Mode | Meaning |
|---|---|
| 0 | Gregorian - apreviated |
| 1 | Gregorian |
| 2 | Julian - apreviated |
| 3 | Julian |
| 4 | Jewish |
| 5 | French Republican |
mixed jddayofweek(int julianday, int mode);Returns the day of the week. Can return a string or an int depending on the mode.
Table 1. Calendar week modes
| Mode | Meaning |
|---|---|
| 0 | returns the day number as an int (0=sunday, 1=monday, etc) |
| 1 | returns string containing the day of week (english-gregorian) |
| 2 | returns a string containing the abreviated day of week (english-gregorian) |
int easter_date(int year);Returns the UNIX timestamp corresponding to midnight on Easter of the given year. If no year is specified, the current year is assumed.
Warning: This function will generate a warning if the year is outside of the range for UNIX timestamps (i.e. before 1970 or after 2037).
Example 1. easter_date() example echo date( "M-d-Y", easter_date(1999) ); /* "Apr-04-1999" */ echo date( "M-d-Y", easter_date(2000) ); /* "Apr-23-2000" */ echo date( "M-d-Y", easter_date(2001) ); /* "Apr-15-2001" */ |
The date of Easter Day was defined by the Council of Nicaea in AD325 as the Sunday after the first full moon which falls on or after the Spring Equinox. The Equinox is assumed to always fall on 21st March, so the calculation reduces to determining the date of the full moon and the date of the following Sunday. The algorithm used here was introduced around the year 532 by Dionysius Exiguus. Under the Julian Calendar (for years before 1753) a simple 19-year cycle is used to track the phases of the Moon. Under the Gregorian Calendar (for years after 1753 - devised by Clavius and Lilius, and introduced by Pope Gregory XIII in October 1582, and into Britain and its then colonies in September 1752) two correction factors are added to make the cycle more accurate.
(The code is based on a C program by Simon Kershaw, <webmaster@ely.anglican.org>)
See easter_days() for calculating Easter before 1970 or after 2037.
int easter_days(int year);Returns the number of days after March 21 on which Easter falls for a given year. If no year is specified, the current year is assumed.
This function can be used instead of easter_date() to calculate Easter for years which fall outside the range of UNIX timestamps (i.e. before 1970 or after 2037).
Example 1. easter_date() example echo easter_days(1999); /* 14, i.e. April 4 */ echo easter_days(1492); /* 32, i.e. April 22 */ echo easter_days(1913); /* 2, i.e. March 23 */ |
The date of Easter Day was defined by the Council of Nicaea in AD325 as the Sunday after the first full moon which falls on or after the Spring Equinox. The Equinox is assumed to always fall on 21st March, so the calculation reduces to determining the date of the full moon and the date of the following Sunday. The algorithm used here was introduced around the year 532 by Dionysius Exiguus. Under the Julian Calendar (for years before 1753) a simple 19-year cycle is used to track the phases of the Moon. Under the Gregorian Calendar (for years after 1753 - devised by Clavius and Lilius, and introduced by Pope Gregory XIII in October 1582, and into Britain and its then colonies in September 1752) two correction factors are added to make the cycle more accurate.
(The code is based on a C program by Simon Kershaw, <webmaster@ely.anglican.org>)
See also easter_date().
ClibPDF allows to create pdf documents with PHP. It is available at FastIO but is not free software. You should definitely read the licence before you start playing with ClibPDF. If you cannot fullfil the licence agreement consider using pdflib by Thomas Merz, which is also very powerful. ClibPDF functionality and API is similar to Thomas Merz pdflib but ClibPDF is, according to FastIO, faster and creates smaller documents. This may have changed with the new version 2.0 of pdflib. A simple benchmark (the pdfclock.c example from pdflib 2.0 turned into a php script) actually show no difference in speed at all. The file size is also similar if compression is turned off.
This documentation should be read with the ClibPDF manual since it explains much of the library in much more detail. Once you understand the manual of ClibPDF you should be able to start using the library with PHP.
Many functions in the native ClibPDF and the PHP module, as well as in pdflib, have the same name. All functions except for cpdf_open() take as their first parameter the handle for the document on which the function is to be performed. Currently this handle is not used internally since ClibPDF does not support the creation of several PDF documents at the same time. Actually, you should not even try it, the results are unpredictable. I cannot oversee what the consequences in a multi threaded environment are. According to the author of ClibPDF this will change in one of the next releases (current version when this was written is 1.10). If you need this functionality use the pdflib module.
One big advantage of ClibPDF over pdflib is the possibility to create the pdf document completely in memory without using temporary files. It also provides the ability to pass coordinates in a predefined unit length. This is a handy feature but can be simulated with pdf_translate().
Most of the functions are fairly easy to use. The most difficult part is probably creating a very simple PDF document at all. The following example should help you get started. It creates a document with one page. The page contains the text "Times-Roman" in an outlined 30pt font. The text is underlined.
Example 1. Simple ClibPDF Example <?php
$cpdf = cpdf_open(0);
cpdf_page_init($cpdf, 1, 0, 595, 842);
cpdf_add_outline($cpdf, 0, 0, 0, 1, "Page 1");
cpdf_set_font($cpdf, "Times-Roman", 30, 4);
cpdf_set_text_rendering($cpdf, 1);
cpdf_text($cpdf, "Times Roman outlined", 50, 750);
cpdf_moveto($cpdf, 50, 740);
cpdf_lineto($cpdf, 330, 740);
cpdf_stroke($cpdf);
cpdf_finalize($cpdf);
Header("Content-type: application/pdf");
cpdf_output_buffer($cpdf);
cpdf_close($cpdf);
?>
|
The pdflib distribution contains a more complex example which creates a series of pages with an analog clock. Here is that example converted into PHP using the ClibPDF extension:
Example 2. pdfclock example from pdflib 2.0 distribution <?php
$radius = 200;
$margin = 20;
$pagecount = 40;
$pdf = cpdf_open(0);
cpdf_set_creator($pdf, "pdf_clock.php3");
cpdf_set_title($pdf, "Analog Clock");
while($pagecount-- > 0) {
cpdf_page_init($pdf, $pagecount+1, 0, 2 * ($radius + $margin), 2 * ($radius + $margin), 1.0);
cpdf_set_page_animation($pdf, 4, 0.5, 0, 0, 0); /* wipe */
cpdf_translate($pdf, $radius + $margin, $radius + $margin);
cpdf_save($pdf);
cpdf_setrgbcolor($pdf, 0.0, 0.0, 1.0);
/* minute strokes */
cpdf_setlinewidth($pdf, 2.0);
for ($alpha = 0; $alpha < 360; $alpha += 6)
{
cpdf_rotate($pdf, 6.0);
cpdf_moveto($pdf, $radius, 0.0);
cpdf_lineto($pdf, $radius-$margin/3, 0.0);
cpdf_stroke($pdf);
}
cpdf_restore($pdf);
cpdf_save($pdf);
/* 5 minute strokes */
cpdf_setlinewidth($pdf, 3.0);
for ($alpha = 0; $alpha < 360; $alpha += 30)
{
cpdf_rotate($pdf, 30.0);
cpdf_moveto($pdf, $radius, 0.0);
cpdf_lineto($pdf, $radius-$margin, 0.0);
cpdf_stroke($pdf);
}
$ltime = getdate();
/* draw hour hand */
cpdf_save($pdf);
cpdf_rotate($pdf, -(($ltime['minutes']/60.0) + $ltime['hours'] - 3.0) * 30.0);
cpdf_moveto($pdf, -$radius/10, -$radius/20);
cpdf_lineto($pdf, $radius/2, 0.0);
cpdf_lineto($pdf, -$radius/10, $radius/20);
cpdf_closepath($pdf);
cpdf_fill($pdf);
cpdf_restore($pdf);
/* draw minute hand */
cpdf_save($pdf);
cpdf_rotate($pdf, -(($ltime['seconds']/60.0) + $ltime['minutes'] - 15.0) * 6.0);
cpdf_moveto($pdf, -$radius/10, -$radius/20);
cpdf_lineto($pdf, $radius * 0.8, 0.0);
cpdf_lineto($pdf, -$radius/10, $radius/20);
cpdf_closepath($pdf);
cpdf_fill($pdf);
cpdf_restore($pdf);
/* draw second hand */
cpdf_setrgbcolor($pdf, 1.0, 0.0, 0.0);
cpdf_setlinewidth($pdf, 2);
cpdf_save($pdf);
cpdf_rotate($pdf, -(($ltime['seconds'] - 15.0) * 6.0));
cpdf_moveto($pdf, -$radius/5, 0.0);
cpdf_lineto($pdf, $radius, 0.0);
cpdf_stroke($pdf);
cpdf_restore($pdf);
/* draw little circle at center */
cpdf_circle($pdf, 0, 0, $radius/30);
cpdf_fill($pdf);
cpdf_restore($pdf);
cpdf_finalize_page($pdf, $pagecount+1);
}
cpdf_finalize($pdf);
Header("Content-type: application/pdf");
cpdf_output_buffer($pdf);
cpdf_close($pdf);
?>
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void cpdf_set_creator(string creator);The cpdf_set_creator() function sets the creator of a pdf document.
See also cpdf_set_subject(), cpdf_set_title(), cpdf_set_keywords().
void cpdf_set_title(string title);The cpdf_set_title() function sets the title of a pdf document.
See also cpdf_set_subject(), cpdf_set_creator(), cpdf_set_keywords().
void cpdf_set_subject(string subject);The cpdf_set_subject() function sets the subject of a pdf document.
See also cpdf_set_title(), cpdf_set_creator(), cpdf_set_keywords().
void cpdf_set_keywords(string keywords);The cpdf_set_keywords() function sets the keywords of a pdf document.
See also cpdf_set_title(), cpdf_set_creator(), cpdf_set_subject().
int cpdf_open(int compression, string filename);The cpdf_open() function opens a new pdf document. The first parameter turns document compression on if it is unequal to 0. The second optional parameter sets the file in which the document is written. If it is omitted the document is created in memory and can either be written into a file with the cpdf_save_to_file() or written to standard output with cpdf_output_buffer().
Note: The return value will be needed in futher versions of ClibPDF as the first parameter in all other functions which are writing to the pdf document.
The ClibPDF library takes the filename "-" as a synonym for stdout. If PHP is compiled as an apache module this will not work because the way ClibPDF outputs to stdout does not work with apache. You can solve this problem by skipping the filename and using cpdf_output_buffer() to output the pdf document.
See also cpdf_close(), cpdf_output_buffer().
void cpdf_close(int pdf document);The cpdf_close() function closes the pdf document. This should be the last function even after cpdf_finalize(), cpdf_output_buffer() and cpdf_save_to_file().
See also cpdf_open().
void cpdf_page_init(int pdf document, int page number, int orientation, double height, double width, double unit);The cpdf_page_init() function starts a new page with height height and width width. The page has number page number and orientation orientation. orientation can be 0 for portrait and 1 for landscape. The last optional parameter unit sets the unit for the koordinate system. The value should be the number of postscript points per unit. Since one inch is equal to 72 points, a value of 72 would set the unit to one inch. The default is also 72.
See also cpdf_set_current_page().
void cpdf_finalize_page(int pdf document, int page number);The cpdf_finalize_page() function ends the page with page number page number. This function is only for saving memory. A finalized page takes less memory but cannot be modified anymore.
See also cpdf_page_init().
void cpdf_finalize(int pdf document);The cpdf_finalize() function ends the document. You still have to call cpdf_close().
See also cpdf_close().
void cpdf_output_buffer(int pdf document);The cpdf_output_buffer() function outputs the pdf document to stdout. The document has to be created in memory which is the case if cpdf_open() has been called with no filename parameter.
See also cpdf_open().
void cpdf_save_to_file(int pdf document, string filename);The cpdf_save_to_file() function outputs the pdf document into a file if it has been created in memory. This function is not needed if the pdf document has been open by specifying a filename as a parameter of cpdf_open().
See also cpdf_output_buffer(), cpdf_open().
void cpdf_set_current_page(int pdf document, int page number);The cpdf_set_current_page() function set the page on which all operations are performed. One can switch between pages until a page is finished with cpdf_finalize_page().
See also cpdf_finalize_page().
void cpdf_begin_text(int pdf document);The cpdf_begin_text() function starts a text section. It must be ended with cpdf_end_text().
Example 1. Text output <?php cpdf_begin_text($pdf); cpdf_set_font($pdf, 16, "Helvetica", 4); cpdf_text($pdf, 100, 100, "Some text"); cpdf_end_text($pdf) ?> |
See also cpdf_end_text().
void cpdf_end_text(int pdf document);The cpdf_end_text() function ends a text section which was started with cpdf_begin_text().
Example 1. Text output <?php cpdf_begin_text($pdf); cpdf_set_font($pdf, 16, "Helvetica", 4); cpdf_text($pdf, 100, 100, "Some text"); cpdf_end_text($pdf) ?> |
See also cpdf_begin_text().
void cpdf_show(int pdf document, string text);The cpdf_show() function outputs the string in text at the current position.
See also cpdf_text(), cpdf_begin_text(), cpdf_end_text().
void cpdf_show_xy(int pdf document, string text, double x-koor, double y-koor, int mode);The cpdf_show_xy() function outputs the string text at position with coordinates (x-koor, y-koor). The last optional parameter determines the unit length. If is 0 or omitted the default unit as specified for the page is used. Otherwise the koodinates are measured in postscript points disregarding the current unit.
Note: The function cpdf_show_xy() is identical to cpdf_text() without the optional parameters.
See also cpdf_text().
void cpdf_text(int pdf document, string text, double x-koor, double y-koor, int mode, double orientation, int alignmode);The cpdf_text() function outputs the string text at position with coordinates (x-koor, y-koor). The optional parameter determines the unit length. If is 0 or omitted the default unit as specified for the page is used. Otherwise the koodinates are measured in postscript points disregarding the current unit. The optional parameter orientation is the rotation of the text in degree. The optional parameter alignmode determines how the text is align. See the ClibPDF documentation for possible values.
See also cpdf_show_xy().
void cpdf_set_font(int pdf document, string font name, double size, int encoding);The cpdf_set_font() function sets the the current font face, font size and encoding. Currently only the standard postscript fonts are supported. The last parameter encoding can take the following values: 2 = macroman, 3 = macexpert, 4 = winansi. Any other value selects the font's buildin encoding.
void cpdf_set leading(int pdf document, double distance);The cpdf_set_leading() function sets the distance between text lines. This will be used if text is output by cpdf_continue_text().
See also cpdf_continue_text().
void cpdf_set_text_rendering(int pdf document, int mode);The cpdf_set_text_rendering() function determines how text is rendered. The possible values for mode are 0=fill text, 1=stroke text, 2=fill and stroke text, 3=invisible, 4=fill text and add it to cliping path, 5=stroke text and add it to clipping path, 6=fill and stroke text and add it to cliping path, 7=add it to clipping path.
void cpdf_set_horiz_scaling(int pdf document, double scale);The cpdf_set_horiz_scaling() function sets the horizontal scaling to scale percent.
void cpdf_set_text_rise(int pdf document, double value);The cpdf_set_text_rise() function sets the text rising to value units.
void cpdf_set_text_matrix(int pdf document, array matrix);The cpdf_set_text_matrix() function sets a matrix which describes a transformation applied on the current text font.
void cpdf_set_text_pos(int pdf document, double x-koor, double y-koor, int mode);The cpdf_set_text_pos() function sets the position of text for the next cpdf_show() function call.
The last optional parameter mode determines the unit length. If is 0 or omitted the default unit as specified for the page is used. Otherwise the koodinates are measured in postscript points disregarding the current unit.
See also cpdf_show(), cpdf_text().
void cpdf_set_char_spacing(int pdf document, double space);The cpdf_set_char_spacing() function sets the spacing between characters.
See also cpdf_set_word_spacing(), cpdf_set_leading().
void cpdf_set_word_spacing(int pdf document, double space);The cpdf_set_word_spacing() function sets the spacing between words.
See also cpdf_set_char_spacing(), cpdf_set_leading().
void cpdf_continue_text(int pdf document, string text);The cpdf_continue_text() function outputs the string in text in the next line.
See also cpdf_show_xy(), cpdf_text(), cpdf_set_leading(), cpdf_set_text_pos().
double cpdf_stringwidth(int pdf document, string text);The cpdf_stringwidth() function returns the width of the string in text. It requires a font to be set before.
See also cpdf_set_font().
void cpdf_save(int pdf document);The cpdf_save() function saves the current enviroment. It works like the postscript command gsave. Very useful if you want to translate or rotate an object without effecting other objects.
See also cpdf_restore().
void cpdf_restore(int pdf document);The cpdf_restore() function restores the enviroment saved with cpdf_save(). It works like the postscript command grestore. Very useful if you want to translate or rotate an object without effecting other objects.
Example 1. Save/Restore <?php cpdf_save($pdf); // do all kinds of rotations, transformations, ... cpdf_restore($pdf) ?> |
See also cpdf_save().
void cpdf_translate(int pdf document, double x-koor, double y-koor, int mode);The cpdf_translate() function set the origin of coordinate system to the point (x-koor, y-koor).
The last optional parameter determines the unit length. If is 0 or omitted the default unit as specified for the page is used. Otherwise the koodinates are measured in postscript points disregarding the current unit.
void cpdf_scale(int pdf document, double x-scale, double y-scale);The cpdf_scale() function set the scaling factor in both directions.
void cpdf_rotate(int pdf document, double angle);The cpdf_rotate() function set the rotation in degress to angle.
void cpdf_setflat(int pdf document, double value);The cpdf_setflat() function set the flatness to a value between 0 and 100.
void cpdf_setlinejoin(int pdf document, long value);The cpdf_setlinejoin() function set the linejoin parameter between a value of 0 and 2. 0 = miter, 1 = round, 2 = bevel.
void cpdf_setlinecap(int pdf document, int value);The cpdf_setlinecap() function set the linecap parameter between a value of 0 and 2. 0 = butt end, 1 = round, 2 = projecting square.
void cpdf_setmiterlimit(int pdf document, double value);The cpdf_setmiterlimit() function set the miter limit to a value greater or equal than 1.
void cpdf_setlinewidth(int pdf document, double width);The cpdf_setlinewidth() function set the line width to width.
void cpdf_setdash(int pdf document, double white, double black);The cpdf_setdash() function set the dash pattern white white units and black black units. If both are 0 a solid line is set.
void cpdf_moveto(int pdf document, double x-koor, double y-koor, int mode);The cpdf_moveto() function set the current point to the coordinates x-koor and y-koor.
The last optional parameter determines the unit length. If is 0 or omitted the default unit as specified for the page is used. Otherwise the koodinates are measured in postscript points disregarding the current unit.
void cpdf_rmoveto(int pdf document, double x-koor, double y-koor, int mode);The cpdf_rmoveto() function set the current point relative to the coordinates x-koor and y-koor.
The last optional parameter determines the unit length. If is 0 or omitted the default unit as specified for the page is used. Otherwise the koodinates are measured in postscript points disregarding the current unit.
See also cpdf_moveto().
void cpdf_curveto(int pdf document, double x1, double y1, double x2, double y2, double x3, double y3, int mode);The cpdf_curveto() function draws a Bezier curve from the current point to the point (x3, y3) using (x1, y1) and (x2, y2) as control points.
The last optional parameter determines the unit length. If is 0 or omitted the default unit as specified for the page is used. Otherwise the koodinates are measured in postscript points disregarding the current unit.
See also cpdf_moveto(), cpdf_rmoveto(), cpdf_rlineto(), cpdf_lineto().
void cpdf_lineto(int pdf document, double x-koor, double y-koor, int mode);The cpdf_lineto() function draws a line from the current point to the point with coordinates (x-koor, y-koor).
The last optional parameter determines the unit length. If is 0 or omitted the default unit as specified for the page is used. Otherwise the koodinates are measured in postscript points disregarding the current unit.
See also cpdf_moveto(), cpdf_rmoveto(), cpdf_curveto().
void cpdf_rlineto(int pdf document, double x-koor, double y-koor, int mode);The cpdf_rlineto() function draws a line from the current point to the relative point with coordinates (x-koor, y-koor).
The last optional parameter determines the unit length. If is 0 or omitted the default unit as specified for the page is used. Otherwise the koodinates are measured in postscript points disregarding the current unit.
See also cpdf_moveto(), cpdf_rmoveto(), cpdf_curveto().
void cpdf_circle(int pdf document, double x-koor, double y-koor, double radius, int mode);The cpdf_circle() function draws a circle with center at point (x-koor, y-koor) and radius radius.
The last optional parameter determines the unit length. If is 0 or omitted the default unit as specified for the page is used. Otherwise the koodinates are measured in postscript points disregarding the current unit.
See also cpdf_arc().
void cpdf_arc(int pdf document, double x-koor, double y-koor, double radius, double start, double end, int mode);The cpdf_arc() function draws an arc with center at point (x-koor, y-koor) and radius radius, starting at angle start and ending at angle end.
The last optional parameter determines the unit length. If is 0 or omitted the default unit as specified for the page is used. Otherwise the koodinates are measured in postscript points disregarding the current unit.
See also cpdf_circle().
void cpdf_rect(int pdf document, double x-koor, double y-koor, double width, double height, int mode);The cpdf_rect() function draws a rectangle with its lower left corner at point (x-koor, y-koor). This width is set to widgth. This height is set to height.
The last optional parameter determines the unit length. If is 0 or omitted the default unit as specified for the page is used. Otherwise the koodinates are measured in postscript points disregarding the current unit.
void cpdf_closepath(int pdf document);The cpdf_closepath() function closes the current path.
void cpdf_stroke(int pdf document);The cpdf_stroke() function draws a line along current path.
See also cpdf_closepath(), cpdf_closepath_stroke().
void cpdf_closepath_stroke(int pdf document);The cpdf_closepath_stroke() function is a combination of cpdf_closepath() and cpdf_stroke(). Than clears the path.
See also cpdf_closepath(), cpdf_stroke().
void cpdf_fill(int pdf document);The cpdf_fill() function fills the interior of the current path with the current fill color.
See also cpdf_closepath(), cpdf_stroke(), cpdf_setgray_fill(), cpdf_setgray(), cpdf_setrgbcolor_fill(), cpdf_setrgbcolor().
void cpdf_fill_stroke(int pdf document);The cpdf_fill_stroke() function fills the interior of the current path with the current fill color and draws current path.
See also cpdf_closepath(), cpdf_stroke(), cpdf_fill(), cpdf_setgray_fill(), cpdf_setgray(), cpdf_setrgbcolor_fill(), cpdf_setrgbcolor().
void cpdf_closepath_fill_stroke(int pdf document);The cpdf_closepath_fill_stroke() function closes, fills the interior of the current path with the current fill color and draws current path.
See also cpdf_closepath(), cpdf_stroke(), cpdf_fill(), cpdf_setgray_fill(), cpdf_setgray(), cpdf_setrgbcolor_fill(), cpdf_setrgbcolor().
void cpdf_clip(int pdf document);The cpdf_clip() function clips all drawing to the current path.
void cpdf_setgray_fill(int pdf document, double value);The cpdf_setgray_fill() function sets the current gray value to fill a path.
See also cpdf_setrgbcolor_fill().
void cpdf_setgray_stroke(int pdf document, double gray value);The cpdf_setgray_stroke() function sets the current drawing color to the given gray value.
See also cpdf_setrgbcolor_stroke().
void cpdf_setgray(int pdf document, double gray value);The cpdf_setgray_stroke() function sets the current drawing and filling color to the given gray value.
See also cpdf_setrgbcolor_stroke(), cpdf_setrgbcolor_fill().
void cpdf_setrgbcolor_fill(int pdf document, double red value, double green value, double blue value);The cpdf_setrgbcolor_fill() function sets the current rgb color value to fill a path.
See also cpdf_setrgbcolor_stroke(), cpdf_setrgbcolor().
void cpdf_setrgbcolor_stroke(int pdf document, double red value, double green value, double blue value);The cpdf_setrgbcolor_stroke() function sets the current drawing color to the given rgb color value.
See also cpdf_setrgbcolor_fill(), cpdf_setrgbcolor().
void cpdf_setrgbcolor(int pdf document, double red value, double green value, double blue value);The cpdf_setrgbcolor_stroke() function sets the current drawing and filling color to the given rgb color value.
See also cpdf_setrgbcolor_stroke(), cpdf_setrgbcolor_fill().
void cpdf_add_outline(int pdf document, string text);The cpdf_add_outline() function adds a bookmark with text text that points to the current page.
Example 1. Adding a page outline <?php
$cpdf = cpdf_open(0);
cpdf_page_init($cpdf, 1, 0, 595, 842);
cpdf_add_outline($cpdf, 0, 0, 0, 1, "Page 1");
// ...
// some drawing
// ...
cpdf_finalize($cpdf);
Header("Content-type: application/pdf");
cpdf_output_buffer($cpdf);
cpdf_close($cpdf);
?>
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void cpdf_set_page_animation(int pdf document, int transition, double duration);The cpdf_set_page_animation() function set the transition between following pages.
The value of transition can be
| 0 for none, |
| 1 for two lines sweeping across the screen reveal the page, |
| 2 for multiple lines sweeping across the screen reveal the page, |
| 3 for a box reveals the page, |
| 4 for a single line sweeping across the screen reveals the page, |
| 5 for the old page dissolves to reveal the page, |
| 6 for the dissolve effect moves from one screen edge to another, |
| 7 for the old page is simply replaced by the new page (default) |
The value of duration is the number of seconds between page flipping.
int cpdf_open_jpeg(int pdf document, string file name, double x-koor, double y-koor, double angle, double width, double height, double x-scale, double y-scale, int mode);The cpdf_import_jpeg() function opens an image stored in the file with the name file name. The format of the image has to be jpeg. The image is placed on the current page at position (x-koor, y-koor). The image is rotated by angle degres.
The last optional parameter determines the unit length. If is 0 or omitted the default unit as specified for the page is used. Otherwise the koodinates are measured in postscript points disregarding the current unit.
See also cpdf_place_inline_image(),
void cpdf_place_inline_image(int pdf document, int image, double x-koor, double y-koor, double angle, double width, double height, int mode);The cpdf_place_inline_image() function places an image created with the php image functions on the page at postion (x-koor, y-koor). The image can be scaled at the same time.
The last optional parameter determines the unit length. If is 0 or omitted the default unit as specified for the page is used. Otherwise the koodinates are measured in postscript points disregarding the current unit.
See also cpdf_import_jpeg(),
void cpdf_add_annotation(int pdf document, double llx, double lly, double urx, double ury, string title, string content, int mode);The cpdf_add_annotation() adds a note with the lower left corner at (llx, lly) and the upper right corner at (urx, ury).
The last optional parameter determines the unit length. If is 0 or omitted the default unit as specified for the page is used. Otherwise the koodinates are measured in postscript points disregarding the current unit.
int checkdate(int month, int day, int year);Returns true if the date given is valid; otherwise returns false. Checks the validity of the date formed by the arguments. A date is considered valid if:
year is between 0 and 32767 inclusive
month is between 1 and 12 inclusive
day is within the allowed number of days for the given month. Leap years are taken into consideration.
string date(string format, int
[timestamp]
);Returns a string formatted according to the given format string using the given timestamp or the current local time if no timestamp is given.
The following characters are recognized in the format string:
a - "am" or "pm"
A - "AM" or "PM"
d - day of the month, 2 digits with leading zeros; i.e. "01" to "31"
D - day of the week, textual, 3 letters; i.e. "Fri"
F - month, textual, long; i.e. "January"
h - hour, 12-hour format; i.e. "01" to "12"
H - hour, 24-hour format; i.e. "00" to "23"
g - hour, 12-hour format without leading zeros; i.e. "1" to "12"
G - hour, 24-hour format without leading zeros; i.e. "0" to "23"
i - minutes; i.e. "00" to "59"
j - day of the month without leading zeros; i.e. "1" to "31"
l (lowercase 'L') - day of the week, textual, long; i.e. "Friday"
L - boolean for whether it is a leap year; i.e. "0" or "1"
m - month; i.e. "01" to "12"
n - month without leading zeros; i.e. "1" to "12"
M - month, textual, 3 letters; i.e. "Jan"
s - seconds; i.e. "00" to "59"
S - English ordinal suffix, textual, 2 characters; i.e. "th", "nd"
t - number of days in the given month; i.e. "28" to "31"
U - seconds since the epoch
w - day of the week, numeric, i.e. "0" (Sunday) to "6" (Saturday)
Y - year, 4 digits; i.e. "1999"
y - year, 2 digits; i.e. "99"
z - day of the year; i.e. "0" to "365"
Z - timezone offset in seconds (i.e. "-43200" to "43200")
Example 1. date() example print (date("l dS of F Y h:i:s A"));
print ("July 1, 2000 is on a " . date("l", mktime(0,0,0,7,1,2000)));
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It is possible to use date() and mktime() together to find dates in the future or the past.
Example 2. date() and mktime() example $tomorrow = mktime(0,0,0,date("m") ,date("d")+1,date("Y"));
$lastmonth = mktime(0,0,0,date("m")-1,date("d"), date("Y"));
$nextyear = mktime(0,0,0,date("m"), date("d", date("Y")+1);
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To format dates in other languages, you should use the setlocale() and strftime() functions.
string strftime(string format, int timestamp);Returns a string formatted according to the given format string using the given timestamp or the current local time if no timestamp is given. Month and weekday names and other language dependent strings respect the current locale set with setlocale().
The following conversion specifiers are recognized in the format string:
%a - abbreviated weekday name according to the current locale
%A - full weekday name according to the current locale
%b - abbreviated month name according to the current locale
%B - full month name according to the current locale
%c - preferred date and time representation for the current locale
%d - day of the month as a decimal number (range 00 to 31)
%H - hour as a decimal number using a 24-hour clock (range 00 to 23)
%I - hour as a decimal number using a 12-hour clock (range 01 to 12)
%j - day of the year as a decimal number (range 001 to 366)
%m - month as a decimal number (range 1 to 12)
%M - minute as a decimal number
%p - either `am' or `pm' according to the given time value, or the corresponding strings for the current locale
%S - second as a decimal number
%U - week number of the current year as a decimal number, starting with the first Sunday as the first day of the first week
%W - week number of the current year as a decimal number, starting with the first Monday as the first day of the first week
%w - day of the week as a decimal, Sunday being 0
%x - preferred date representation for the current locale without the time
%X - preferred time representation for the current locale without the date
%y - year as a decimal number without a century (range 00 to 99)
%Y - year as a decimal number including the century
%Z - time zone or name or abbreviation
%% - a literal `%' character
Example 1. strftime() example setlocale ("LC_TIME", "C");
print(strftime("%A in Finnish is "));
setlocale ("LC_TIME", "fi_FI");
print(strftime("%A, in French "));
setlocale ("LC_TIME", "fr_CA");
print(strftime("%A and in German "));
setlocale ("LC_TIME", "de_DE");
print(strftime("%A.\n"));
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See also setlocale() and mktime().
string gmstrftime(string format, int timestamp);Behaves the same as strftime() except that the time returned is Greenwich Mean Time (GMT). For example, when run in Eastern Standard Time (GMT -0500), the first line below prints "Dec 31 1998 20:00:00", while the second prints "Jan 01 1999 01:00:00".
Example 1. gmstrftime() example setlocale ('LC_TIME','en_US');
echo strftime ("%b %d %Y %H:%M:%S",mktime(20,0,0,12,31,98))."\n";
echo gmstrftime ("%b %d %Y %H:%M:%S",mktime(20,0,0,12,31,98))."\n";
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See also strftime().
array getdate(int timestamp);Returns an associative array containing the date information of the timestamp as the following array elements:
"seconds" - seconds
"minutes" - minutes
"hours" - hours
"mday" - day of the month
"wday" - day of the week, numeric
"mon" - month, numeric
"year" - year, numeric
"yday" - day of the year, numeric; i.e. "299"
"weekday" - day of the week, textual, full; i.e. "Friday"
"month" - month, textual, full; i.e. "January"
array gettimeofday(void);This is an interface to gettimeofday(2). It returns an associative array containing the data returned from the system call.
"sec" - seconds
"usec" - microseconds
"minuteswest" - minutes west of Greenwich
"dsttime" - type of dst correction
string gmdate(string format, int timestamp);Identical to the date() function except that the time returned is Greenwich Mean Time (GMT). For example, when run in Finland (GMT +0200), the first line below prints "Jan 01 1998 00:00:00", while the second prints "Dec 31 1997 22:00:00".
Example 1. gmdate() example echo date( "M d Y H:i:s",mktime(0,0,0,1,1,1998) );
echo gmdate( "M d Y H:i:s",mktime(0,0,0,1,1,1998) );
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See also date(), mktime() and gmmktime().
int mktime(int hour, int minute, int second, int month, int day, int year, int [is_dst]);Warning: Note the strange order of arguments, which differs from the order of arguments in a regular UNIX mktime() call and which does not lend itself well to leaving out parameters from right to left (see below). It is a common error to mix these values up in a script.
Returns the Unix timestamp corresponding to the arguments given. This timestamp is a long integer containing the number of seconds between the Unix Epoch (January 1 1970) and the time specified.
Arguments may be left out in order from right to left; any arguments thus omitted will be set to the current value according to the local date and time.
is_dst can be set to 1 if the time is during daylight savings time, 0 if it is not, or -1 (the default) if it is unknown whether the time is within daylight savings time or not.
Note: is_dst was added in 3.0.10.
mktime() is useful for doing date arithmetic and validation, as it will automatically calculate the correct value for out-of-range input. For example, each of the following lines produces the string "Jan-01-1998".
Example 1. mktime() example echo date( "M-d-Y", mktime(0,0,0,12,32,1997) );
echo date( "M-d-Y", mktime(0,0,0,13,1,1997) );
echo date( "M-d-Y", mktime(0,0,0,1,1,1998) );
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int gmmktime(int hour, int minute, int second, int month, int day, int year, int [is_dst]);Identical to mktime() except the passed parameters represents a GMT date.
int time(void);Returns the current time measured in the number of seconds since the Unix Epoch (January 1 1970 00:00:00 GMT).
See also date().
string microtime(void);Returns the string "msec sec" where sec is the current time measured in the number of seconds since the Unix Epoch (0:00:00 January 1, 1970 GMT), and msec is the microseconds part. This function is only available on operating systems that support the gettimeofday() system call.
See also time().
These functions build the foundation for accessing Berkeley DB style databases.
This is a general abstraction layer for several file-based databases. As such, functionality is limited to a subset of features modern databases such as Sleepycat Software's DB2 support. (This is not to be confused with IBM's DB2 software, which is supported through the ODBC functions.)
The behaviour of various aspects depend on the implementation of the underlying database. Functions such as dba_optimize() and dba_sync() will do what they promise for one database and will do nothing for others.
The following handlers are supported:
dbm is the oldest (original) type of Berkeley DB style databases. You should avoid it, if possible. We do not support the compatibility functions built into DB2 and gdbm, because they are only compatible on the source code level, but cannot handle the original dbm format.
ndbm is a newer type and more flexible than dbm. It still has most of the arbitrary limits of dbm (therefore it is deprecated).
gdbm is the GNU database manager.
db2 is Sleepycat Software's DB2. It is described as "a programmatic toolkit that provides high-performance built-in database support for both standalone and client/server applications."
cdb is "a fast, reliable, lightweight package for creating and reading constant databases." It is from the author of qmail and can be found here. Since it is constant, we support only reading operations.
Example 1. DBA example <?php
$id = dba_open("/tmp/test.db", "n", "db2");
if(!$id) {
echo "dba_open failed\n";
exit;
}
dba_replace("key", "This is an example!", $id);
if(dba_exists("key", $id)) {
echo dba_fetch("key", $id);
dba_delete("key", $id);
}
dba_close($id);
?> |
DBA is binary safe and does not have any arbitrary limits. It inherits all limits set by the underlying database implementation.
All file-based databases must provide a way of setting the file mode of a new created database, if that is possible at all. The file mode is commonly passed as the fourth argument to dba_open() or dba_popen().
You can access all entries of a database in a linear way by using the dba_firstkey() and dba_nextkey() functions. You may not change the database while traversing it.
Example 2. Traversing a database <?php
# ...open database...
$key = dba_firstkey($id);
while($key != false) {
if(...) { # remember the key to perform some action later
$handle_later[] = $key;
}
$key = dba_nextkey($id);
}
for($i = 0; $i < count($handle_later); $i++)
dba_delete($handle_later[$i], $id);
?> |
void dba_close(int handle);dba_close() closes the established database and frees all resources specified by handle.
handle is a database handle returned by dba_open().
dba_close() does not return any value.
See also: dba_open() dba_popen()
string dba_delete(string key, int handle);dba_delete() deletes the entry specified by key from the database specified with handle.
key is the key of the entry which is deleted.
handle is a database handle returned by dba_open().
dba_delete() returns true or false, if the entry is deleted or not deleted, respectively.
See also: dba_exists() dba_fetch() dba_insert() dba_replace()
bool dba_exists(string key, int handle);dba_exists() checks whether the specified key exists in the database specified by handle.
key is the key the check is performed for.
handle is a database handle returned by dba_open().
dba_exists() returns true or false, if the key is found or not found, respectively.
See also: dba_fetch() dba_delete() dba_insert() dba_replace()
string dba_fetch(string key, int handle);dba_fetch() fetches the data specified by key from the database specified with handle.
key is the key the data is specified by.
handle is a database handle returned by dba_open().
dba_fetch() returns the associated string or false, if the key/data pair is found or not found, respectively.
See also: dba_exists() dba_delete() dba_insert() dba_replace()
string dba_firstkey(int handle);dba_firstkey() returns the first key of the database specified by handle and resets the internal key pointer. This permits a linear search through the whole database.
handle is a database handle returned by dba_open().
dba_firstkey() returns the key or false depending on whether it succeeds or fails, respectively.
See also: dba_nextkey()
bool dba_insert(string key, string value, int handle);dba_insert() inserts the entry described with key and value into the database specified by handle. It fails, if an entry with the same key already exists.
key is the key of the entry to be inserted.
value is the value to be inserted.
handle is a database handle returned by dba_open().
dba_insert() returns true or false, depending on whether it succeeds of fails, respectively.
See also: dba_exists() dba_delete() dba_fetch() dba_replace()
string dba_nextkey(int handle);dba_nextkey() returns the next key of the database specified by handle and increments the internal key pointer.
handle is a database handle returned by dba_open().
dba_nextkey() returns the key or false depending on whether it succeeds or fails, respectively.
See also: dba_firstkey()
int dba_popen(string path, string mode, string handler, [...]);dba_popen() establishes a persistent database instance for path with mode using handler.
path is commonly a regular path in your filesystem.
mode is "r" for read access, "w" for read/write access to an already existing database, "c" for read/write access and database creation if it doesn't currently exist, and "n" for create, truncate and read/write access.
handler is the name of the handler which shall be used for accessing path. It is passed all optional parameters given to dba_popen() and can act on behalf of them.
dba_popen() returns a positive handler id or false, in the case the open is successful or fails, respectively.
See also: dba_open() dba_close()
int dba_open(string path, string mode, string handler, [...]);dba_open() establishes a database instance for path with mode using handler.
path is commonly a regular path in your filesystem.
mode is "r" for read access, "w" for read/write access to an already existing database, "c" for read/write access and database creation if it doesn't currently exist, and "n" for create, truncate and read/write access.
handler is the name of the handler which shall be used for accessing path. It is passed all optional parameters given to dba_open() and can act on behalf of them.
dba_open() returns a positive handler id or false, in the case the open is successful or fails, respectively.
See also: dba_popen() dba_close()
bool dba_optimize(int handle);dba_optimize() optimizes the underlying database specified by handle.
handle is a database handle returned by dba_open().
dba_optimize() returns true or false, if the optimization succeeds or fails, respectively.
See also: dba_sync()
bool dba_replace(string key, string value, int handle);dba_replace() replaces or inserts the entry described with key and value into the database specified by handle.
key is the key of the entry to be inserted.
value is the value to be inserted.
handle is a database handle returned by dba_open().
dba_replace() returns true or false, depending on whether it succeeds of fails, respectively.
See also: dba_exists() dba_delete() dba_fetch() dba_insert()
bool dba_sync(int handle);dba_sync() synchronizes the database specified by handle. This will probably trigger a physical write to disk, if supported.
handle is a database handle returned by dba_open().
dba_sync() returns true or false, if the synchronization succeeds or fails, respectively.
See also: dba_optimize()
These functions allow you to access records stored in dBase-format (dbf) databases.
There is no support for indexes or memo fields. There is no support for locking, too. Two concurrent webserver processes modifying the same dBase file will very likely ruin your database.
Unlike SQL databases, dBase "databases" cannot change the database definition afterwards. Once the file is created, the database definition is fixed. There are no indexes that speed searching or otherwise organize your data. dBase files are simple sequential files of fixed length records. Records are appended to the end of the file and delete records are kept until you call dbase_pack()().
We recommend that you do not use dBase files as your production database. Choose any real SQL server instead; MySQL or Postgres are common choices with PHP. dBase support is here to allow you to import and export data to and from your web database, since the file format is commonly understood with Windows spreadsheets and organizers. Import and export of data is about all that dBase support is good for.
int dbase_create(string filename, array fields);The fields parameter is an array of arrays, each array describing the format of one field in the database. Each field consists of a name, a character indicating the field type, a length, and a precision.
The types of fields available are:
Boolean. These do not have a length or precision.
Memo. (Note that these aren't supported by PHP.) These do not have a length or precision.
Date (stored as YYYYMMDD). These do not have a length or precision.
Number. These have both a length and a precision (the number of digits after the decimal point).
String.
If the database is successfully created, a dbase_identifier is returned, otherwise false is returned.
Example 1. Creating a dBase database file // "database" name
$dbname = "/tmp/test.dbf";
// database "definition"
$def =
array(
array("date", "D"),
array("name", "C", 50),
array("age", "N", 3, 0),
array("email", "C", 128),
array("ismember", "L")
);
// creation
if (!dbase_create($dbname, $def))
print "<strong>Error!</strong>";
|
int dbase_open(string filename, int flags);The flags correspond to those for the open() system call. (Typically 0 means read-only, 1 means write-only, and 2 means read and write.)
Returns a dbase_identifier for the opened database, or false if the database couldn't be opened.
bool dbase_close(int dbase_identifier);Closes the database associated with dbase_identifier.
bool dbase_pack(int dbase_identifier);Packs the specified database (permanently deleting all records marked for deletion using dbase_delete_record().
bool dbase_add_record(int dbase_identifier, array record);Adds the data in the record to the database. If the number of items in the supplied record isn't equal to the number of fields in the database, the operation will fail and false will be returned.
bool dbase_replace_record(int dbase_identifier, array record, int dbase_record_number);Replaces the data associated with the record record_number with the data in the record in the database. If the number of items in the supplied record is not equal to the number of fields in the database, the operation will fail and false will be returned.
dbase_record_number is an integer which spans from 1 to the number of records in the database (as returned by dbase_numrecords()).
bool dbase_delete_record(int dbase_identifier, int record);Marks record to be deleted from the database. To actually remove the record from the database, you must also call dbase_pack().
array dbase_get_record(int dbase_identifier, int record);Returns the data from record in an array. The array is indexed starting at 0, and includes an associative member named 'deleted' which is set to 1 if the record has been marked for deletion (see dbase_delete_record().
Each field is converted to the appropriate PHP type. (Dates are left as strings.)
array dbase_get_record_with_names(int dbase_identifier, int record);Returns the data from record in an associative array. The array also includes an associative member named 'deleted' which is set to 1 if the record has been marked for deletion (see dbase_delete_record().
Each field is converted to the appropriate PHP type. (Dates are left as strings.)
int dbase_numfields(int dbase_identifier);Returns the number of fields (columns) in the specified database. Field numbers are between 0 and dbase_numfields($db)-1, while record numbers are between 1 and dbase_numrecords($db).
Example 1. Using dbase_numfields() $rec = dbase_get_record($db, $recno);
$nf = dbase_numfields($db);
for ($i=0; $i < $nf; $i++) {
print $rec[$i]."<br>\n";
} |
These functions allow you to store records stored in a dbm-style database. This type of database (supported by the Berkeley db, gdbm, and some system libraries, as well as a built-in flatfile library) stores key/value pairs (as opposed to the full-blown records supported by relational databases).
Example 1. dbm example $dbm = dbmopen("lastseen", "w");
if (dbmexists($dbm, $userid)) {
$last_seen = dbmfetch($dbm, $userid);
} else {
dbminsert($dbm, $userid, time());
}
do_stuff();
dbmreplace($dbm, $userid, time());
dbmclose($dbm); |
int dbmopen(string filename, string flags);The first argument is the full-path filename of the dbm file to be opened and the second is the file open mode which is one of "r", "n", "c" or "w" for read-only, new (implies read-write, and most likely will truncate an already-existing database of the same name), create (implies read-write, and will not truncate an already-existing database of the same name) and read-write respectively.
Returns an identifer to be passed to the other dbm functions on success, or false on failure.
If ndbm support is used, ndbm will actually create filename.dir and filename.pag files. gdbm only uses one file, as does the internal flat-file support, and Berkeley db creates a filename.db file. Note that PHP does its own file locking in addition to any file locking that may be done by the dbm library itself. PHP does not delete the .lck files it creates. It uses these files simply as fixed inodes on which to do the file locking. For more information on dbm files, see your Unix man pages, or obtain GNU's gdbm from ftp://prep.ai.mit.edu/pub/gnu.
bool dbmexists(int dbm_identifier, string key);Returns true if there is a value associated with the key.
int dbminsert(int dbm_identifier, string key, string value);Adds the value to the database with the specified key.
Returns -1 if the database was opened read-only, 0 if the insert was successful, and 1 if the specified key already exists. (To replace the value, use dbmreplace().)
bool dbmreplace(int dbm_identifier, string key, string value);Replaces the value for the specified key in the database.
This will also add the key to the database if it didn't already exist.
bool dbmdelete(int dbm_identifier, string key);Deletes the value for key in the database.
Returns false if the key didn't exist in the database.
string dbmfirstkey(int dbm_identifier);Returns the first key in the database. Note that no particular order is guaranteed since the database may be built using a hash-table, which doesn't guarantee any ordering.
string dbmnextkey(int dbm_identifier, string key);Returns the next key after key. By calling dbmfirstkey() followed by successive calls to dbmnextkey() it is possible to visit every key/value pair in the dbm database. For example:
Example 1. Visiting every key/value pair in a dbm database. $key = dbmfirstkey($dbm_id);
while ($key) {
echo "$key = " . dbmfetch($dbm_id, $key) . "\n";
$key = dbmnextkey($dbm_id, $key);
}
|
int chdir(string directory);Changes PHP's current directory to directory. Returns FALSE if unable to change directory, TRUE otherwise.
new dir(string directory);A pseudo-object oriented mechanism for reading a directory. The given directory is opened. Two properties are available once directory has been opened. The handle property can be used with other directory functions such as readdir(), rewinddir() and closedir(). The path property is set to path the directory that was opened. Three methods are available: read, rewind and close.
Example 1. Dir() Example $d = dir("/etc");
echo "Handle: ".$d->handle."<br>\n";
echo "Path: ".$d->path."<br>\n";
while($entry=$d->read()) {
echo $entry."<br>\n";
}
$d->close();
|
void closedir(int dir_handle);Closes the directory stream indicated by dir_handle. The stream must have previously been opened by opendir().
int opendir(string path);Returns a directory handle to be used in subsequent closedir(), readdir(), and rewinddir() calls.
string readdir(int dir_handle);Returns the filename of the next file from the directory. The filenames are not returned in any particular order.
Example 1. List all files in the current directory <?php
$handle=opendir('.');
echo "Directory handle: $handle\n";
echo "Files:\n";
while ($file = readdir($handle)) {
echo "$file\n";
}
closedir($handle);
?>
|
int dl(string library);Loads the PHP extension defined in library. See also the extension_dir configuration directive.
string escapeshellcmd(string command);EscapeShellCmd() escapes any characters in a string that might be used to trick a shell command into executing arbitrary commands. This function should be used to make sure that any data coming from user input is escaped before this data is passed to the exec() or system() functions. A standard use would be:
system(EscapeShellCmd($cmd))
string exec(string command, string [array], int [return_var]);exec() executes the given command, however it does not output anything. It simply returns the last line from the result of the command. If you need to execute a command and have all the data from the command passed directly back without any interference, use the PassThru() function.
If the array argument is present, then the specified array will be filled with every line of output from the command. Note that if the array already contains some elements, exec() will append to the end of the array. If you do not want the function to append elements, call unset() on the array before passing it to exec().
If the return_var argument is present along with the array argument, then the return status of the executed command will be written to this variable.
Note that if you are going to allow data coming from user input to be passed to this function, then you should be using EscapeShellCmd() to make sure that users cannot trick the system into executing arbitrary commands.
See also system(), PassThru(), popen() and EscapeShellCmd().
string system(string command, int [return_var]);System() is just like the C version of the function in that it executes the given command and outputs the result. If a variable is provided as the second argument, then the return status code of the executed command will be written to this variable.
Note, that if you are going to allow data coming from user input to be passed to this function, then you should be using the EscapeShellCmd() function to make sure that users cannot trick the system into executing arbitrary commands.
The System() call also tries to automatically flush the web server's output buffer after each line of output if PHP is running as a server module.
If you need to execute a command and have all the data from the command passed directly back without any interference, use the PassThru() function. See also the exec() and popen() functions.
string passthru(string command, int [return_var]);The passthru() function is similar to the Exec() function in that it executes a command. If the return_var argument is present, the return status of the Unix command will be placed here. This function should be used in place of Exec() or System() when the output from the Unix command is binary data which needs to be passed directly back to the browser. A common use for this is to execute something like the pbmplus utilities that can output an image stream directly. By setting the content-type to image/gif and then calling a pbmplus program to output a gif, you can create PHP scripts that output images directly.
See also exec() and fpassthru().
Forms Data Format (FDF) is a format for handling forms within PDF documents. You should read the documentation at http://partners.adobe.com/asn/developer/acrosdk/main.html for more information on what FDF is and how it is used in general.
Note: Currently Adobe only provides a libc5 compatible version for Linux. Tests with glibc2 resulted in a segmentation fault. If somebody is able to make it work, please comment on this page.
The general idea of FDF is similar to HTML forms. The diffence is basically the format how filled in data is transmitted to the server when the submit button is pressed (this is actually the Form Data Format) and the format of the form itself (which is the Portable Document Format, PDF). Processing the FDF data is one of the features provided by the fdf functions. But there is more. One may as well take an existing PDF form and populated the input fields with data without modifying the form itself. In such a case one would create a FDF document (fdf_create()) set the values of each input field (fdf_set_value()) and associate it with a PDF form (fdf_set_file()). Finally it has to be sent to the browser with MimeType application/vnd.fdf. The Acrobat reader plugin of your browser recognizes the MimeType, reads the associated PDF form and fills in the data from the FDF document.
The following examples shows just the evaluation of form data.
Example 1. Evaluating a FDF document <?php
// Save the FDF data into a temp file
$fdffp = fopen("test.fdf", "w");
fwrite($fdffp, $HTTP_FDF_DATA, strlen($HTTP_FDF_DATA));
fclose($fdffp);
// Open temp file and evaluate data
// The pdf form contained several input text fields with the names
// volume, date, comment, publisher, preparer, and two checkboxes
// show_publisher and show_preparer.
$fdf = fdf_open("test.fdf");
$volume = fdf_get_value($fdf, "volume");
echo "The volume field has the value '<B>$volume</B>'<BR>";
$date = fdf_get_value($fdf, "date");
echo "The date field has the value '<B>$date</B>'<BR>";
$comment = fdf_get_value($fdf, "comment");
echo "The comment field has the value '<B>$comment</B>'<BR>";
if(fdf_get_value($fdf, "show_publisher") == "On") {
$publisher = fdf_get_value($fdf, "publisher");
echo "The publisher field has the value '<B>$publisher</B>'<BR>";
} else
echo "Publisher shall not be shown.<BR>";
if(fdf_get_value($fdf, "show_preparer") == "On") {
$preparer = fdf_get_value($fdf, "preparer");
echo "The preparer field has the value '<B>$preparer</B>'<BR>";
} else
echo "Preparer shall not be shown.<BR>";
fdf_close($fdf);
?>
|
int fdf_open(string filename);The fdf_open() function opens a file with form data. This file must contain the data as returned from a PDF form. Currently, the file has to be created 'manually' by using fopen() and writing the content of HTTP_FDF_DATA with fwrite() into it. A mechanism like for HTML form data where for each input field a variable is created does not exist.
Example 1. Accessing the form data <?php
// Save the FDF data into a temp file
$fdffp = fopen("test.fdf", "w");
fwrite($fdffp, $HTTP_FDF_DATA, strlen($HTTP_FDF_DATA));
fclose($fdffp);
// Open temp file and evaluate data
$fdf = fdf_open("test.fdf");
...
fdf_close($fdf);
?>
|
See also fdf_close().
void fdf_close(int fdf_document);The fdf_close() function closes the FDF document.
See also fdf_open().
int fdf_create(void );The fdf_create() creates a new FDF document. This function is needed if one would like to populate input fields in a PDF document with data.
Example 1. Populating a PDF document <?php
$outfdf = fdf_create();
fdf_set_value($outfdf, "volume", $volume, 0);
fdf_set_file($outfdf, "http:/testfdf/resultlabel.pdf");
fdf_save($outfdf, "outtest.fdf");
fdf_close($outfdf);
Header("Content-type: application/vnd.fdf");
$fp = fopen("outtest.fdf", "r");
fpassthru($fp);
unlink("outtest.fdf");
?>
|
See also fdf_close(), fdf_save(), fdf_open().
int fdf_save(string filename);The fdf_save() function saves a FDF document. The FDF Toolkit provides a way to output the document to stdout if the parameter filename is '.'. This does not work if PHP is used as an apache module. In such a case one will have to write to a file and use e.g. fpassthru(). to output it.
See also fdf_close() and example for fdf_create().
string fdf_get_value(int fdf_document, string fieldname);The fdf_get_value() function returns the value of a field.
See also fdf_set_value().
void fdf_set_value(int fdf_document, string fieldname, string value, int isName);The fdf_set_value() function sets the value of a field. The last parameter determines if the field value is to be converted to a PDF Name (isName = 1) or set to a PDF String (isName = 0).
See also fdf_get_value().
string fdf_next_field_name(int fdf_document, string fieldname);The fdf_next_field_name() function returns the name of the field after the field in fieldname or the field name of the first field if the second paramter is NULL.
See also fdf_set_field(), fdf_get_field().
void fdf_set_ap(int fdf_document, string field_name, int face, string filename, int page_number);The fdf_set_ap() function sets the appearance of a field (i.e. the value of the /AP key). The possible values of face are 1=FDFNormalAP, 2=FDFRolloverAP, 3=FDFDownAP.
void fdf_set_status(int fdf_document, string status);The fdf_set_status() sets the value of the /STATUS key.
See also fdf_get_status().
string fdf_get_status(int fdf_document);The fdf_get_status() returns the value of the /STATUS key.
See also fdf_set_status().
void fdf_set_file(int fdf_document, string filename);The fdf_set_file() sets the value of the /F key. The /F key is just a reference to a PDF form which is to be populated with data. In a web environment it is a URL (e.g. http:/testfdf/resultlabel.pdf).
See also fdf_get_file() and example for fdf_create().
string fdf_get_file(int fdf_document);The fdf_set_file() returns the value of the /F key.
See also fdf_set_file().
These functions allow read-only access to data stored in filePro databases.
filePro is a registered trademark of Fiserv, Inc. You can find more information about filePro at http://www.fileproplus.com/.
bool filepro(string directory);This reads and verifies the map file, storing the field count and info.
No locking is done, so you should avoid modifying your filePro database while it may be opened in PHP.
string filepro_fieldname(int field_number);Returns the name of the field corresponding to field_number.
string filepro_fieldtype(int field_number);Returns the edit type of the field corresponding to field_number.
int filepro_fieldwidth(int field_number);Returns the width of the field corresponding to field_number.
string filepro_retrieve(int row_number, int field_number);Returns the data from the specified location in the database.
int filepro_fieldcount(void);Returns the number of fields (columns) in the opened filePro database.
See also filepro().
int filepro_rowcount(void);Returns the number of rows in the opened filePro database.
See also filepro().
string basename(string path);Given a string containing a path to a file, this function will return the base name of the file.
On Windows, both slash (/) and backslash (\) are used as path separator character. In other environments, it is the forward slash (/).
Example 1. basename() example $path = "/home/httpd/html/index.php3"; $file = basename($path); // $file is set to "index.php3" |
See also: dirname()
int chgrp(string filename, mixed group);Attempts to change the group of the file filename to group. Only the superuser may change the group of a file arbitrarily; other users may change the group of a file to any group of which that user is a member.
Returns true on success; otherwise returns false.
On Windows, does nothing and returns true.
int chmod(string filename, int mode);Attempts to change the mode of the file specified by filename to that given in mode.
Note that mode is not automatically assumed to be an octal value. To ensure the expected operation, you need to prefix mode with a zero (0):
chmod( "/somedir/somefile", 755 ); // decimal; probably incorrect
chmod( "/somedir/somefile", 0755 ); // octal; correct value of mode
Returns true on success and false otherwise.
int chown(string filename, mixed user);Attempts to change the owner of the file filename to user user. Only the superuser may change the owner of a file.
Returns true on success; otherwise returns false.
Note: On Windows, does nothing and returns true.
See also chown() and chmod().
void clearstatcache(void);Invoking the stat or lstat system call on most systems is quite expensive. Therefore, the result of the last call to any of the status functions (listed below) is stored for use on the next such call using the same filename. If you wish to force a new status check, for instance if the file is being checked many times and may change or disappear, use this function to clear the results of the last call from memory.
This value is only cached for the lifetime of a single request.
Affected functions include stat(), lstat(), file_exists(), is_writeable(), is_readable(), is_executable(), is_file(), is_dir(), is_link(), filectime(), fileatime(), filemtime(), fileinode(), filegroup(), fileowner(), filesize(), filetype(), and fileperms().
int copy(string source, string dest);Makes a copy of a file. Returns true if the copy succeeded, false otherwise.
Example 1. copy() example if (!copy($file, $file.'.bak')) {
print("failed to copy $file...<br>\n");
} |
See also: rename()
void delete(string file);This is a dummy manual entry to satisfy those people who are looking for unlink() or unset() in the wrong place.
See also: unlink() to delete files, unset() to delete variables.
string dirname(string path);Given a string containing a path to a file, this function will return the name of the directory.
On Windows, both slash (/) and backslash (\) are used as path separator character. In other environments, it is the forward slash (/).
Example 1. dirname() example $path = "/etc/passwd"; $file = dirname($path); // $file is set to "/etc" |
See also: basename()
float diskfreespace(string directory);Given a string containing a directory, this function will return the number of bytes available on the corresponding disk.
Example 1. diskfreespace() example $df = diskfreespace("/"); // $df contains the number of bytes available on "/" |
int fclose(int fp);The file pointed to by fp is closed.
Returns true on success and false on failure.
The file pointer must be valid, and must point to a file successfully opened by fopen() or fsockopen().
int feof(int fp);Returns true if the file pointer is at EOF or an error occurs; otherwise returns false.
The file pointer must be valid, and must point to a file successfully opened by fopen(), popen(), or fsockopen().
string fgetc(int fp);Returns a string containing a single character read from the file pointed to by fp. Returns FALSE on EOF (as does feof()).
The file pointer must be valid, and must point to a file successfully opened by fopen(), popen(), or fsockopen().
See also fread(), fopen(), popen(), fsockopen(), and fgets().
array fgetcsv(int fp, int length, string [delimiter]);Similar to fgets() except that fgetcsv() parses the line it reads for fields in CSV format and returns an array containing the fields read. The field delimiter is a comma, unless you specifiy another delimiter with the optional third parameter.
fp must be a valid file pointer to a file successfully opened by fopen(), popen(), or fsockopen()
length must be greater than the longest line to be found in the CSV file (allowing for trailing line-end characters).
fgetcsv() returns false on error, including end of file.
NB A blank line in a CSV file will be returned as an array comprising just one single null field, and will not be treated as an error.
Example 1. fgetcsv() example - Read and print entire contents of a CSV file $row=1;
$fp = fopen("test.csv","r");
while ($data = fgetcsv($fp,1000, ",")) {
$num = count($data);
print "<p> $num fields in line $row: <br>";
$row++;
for ( $c=0; $c<$num; $c++ ) print $data[$c] . "<br>";
}
fclose($fp);
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string fgets(int fp, int length);Returns a string of up to length - 1 bytes read from the file pointed to by fp. Reading ends when length - 1 bytes have been read, on a newline (which is included in the return value), or on EOF (whichever comes first).
If an error occurs, returns false.
Common Pitfalls:
People used to the 'C' semantics of fgets should note the difference in how EOF is returned.
The file pointer must be valid, and must point to a file successfully opened by fopen(), popen(), or fsockopen().
A simple example follows:
Example 1. Reading a file line by line $fd = fopen("/tmp/inputfile.txt", "r");
while ($buffer = fgets($fd, 4096)) {
echo $buffer;
}
fclose($fd); |
See also fread(), fopen(), popen(), fgetc(), and fsockopen().
string fgetss(int fp, int length);Identical to fgets(), except that fgetss attempts to strip any HTML and PHP tags from the text it reads.
See also fgets(), fopen(), fsockopen(), popen(), and strip_tags().
array file(string filename);Identical to readfile(), except that file() returns the file in an array. Each element of the array corresponds to a line in the file, with the newline still attached.
See also readfile(), fopen(), and popen().
int file_exists(string filename);Returns true if the file specified by filename exists; false otherwise.
The results of this function are cached. See clearstatcache() for more details.
int fileatime(string filename);Returns the time the file was last accessed, or false in case of an error.
The results of this function are cached. See clearstatcache() for more details.
int filectime(string filename);Returns the time the file was last changed, or false in case of an error.
The results of this function are cached. See clearstatcache() for more details.
int filegroup(string filename);Returns the group ID of the owner of the file, or false in case of an error.
The results of this function are cached. See clearstatcache() for more details.
int fileinode(string filename);Returns the inode number of the file, or false in case of an error.
The results of this function are cached. See clearstatcache() for more details.
int filemtime(string filename);Returns the time the file was last modified, or false in case of an error.
The results of this function are cached. See clearstatcache() for more details.
int fileowner(string filename);Returns the user ID of the owner of the file, or false in case of an
The results of this function are cached. See clearstatcache() for more details. error.
int fileperms(string filename);Returns the permissions on the file, or false in case of an error.
The results of this function are cached. See clearstatcache() for more details.
int filesize(string filename);Returns the size of the file, or false in case of an error.
The results of this function are cached. See clearstatcache() for more details.
string filetype(string filename);Returns the type of the file. Possible values are fifo, char, dir, block, link, file, and unknown.
Returns false if an error occurs.
The results of this function are cached. See clearstatcache() for more details.
bool flock(int fp, int operation);PHP supports a portable way of locking complete files in an advisory way (which means all accessing programs have to use the same way of locking or it will not work).
flock() operates on fp which must be an open file pointer. operation is one of the following values:
To acquire a shared lock (reader), set operation to 1.
To acquire an exclusive lock (writer), set operation to 2.
To release a lock (shared or exclusive), set operation to 3.
If you don't want flock() t