====== PHP Configuration for DokuWiki =======

DokuWiki will run out of the box on nearly every PHP installation and the [[:installer]] will check that the minimum of needed PHP functionality is available.

This page gives hints on how to tune [[http://www.php.net/|PHP]] settings to influence the functionality, performance, security and portability of DokuWiki. 

Please consult the online [[http://www.php.net/manual/en/|PHP manual]] for more details.


===== PHP extensions =====

Below you can find which extensions should be enabled for your PHP setup. On some systems these extension might need to be installed separately, other systems might bundle them in a single install package and only need them to be enabled in ''php.ini''

==== required ====

These extensions are usually enabled by default anyway.

  * ''json'' -- JSON decoding, encoding
  * ''pcre'' -- Regular expression handling
  * ''session'' -- Session handling
  

==== recommended ====

  * ''bz2'' -- compression handling for attic files, plugin installs
  * ''gd'' -- image resizing
  * ''intl'' -- internationalization handling, for example for locale aware sorting
  * ''mbstring'' -- faster UTF-8 handling
  * ''openssl'' -- SSL/TLS connections, used for plugin downloading
  * ''zlib'' -- compression handling for attic files, plugin installs

==== special use cases ====

The following extensions are often used by plugins and thus might come in handy.

  * ''pdo_sqlite'' -- used by the [[plugin:sqlite]] plugin
  * ''xml''


===== php.ini =====

The basic means of configuring PHP is via a configuration file (''php.ini'').

For the server module versions of PHP, this file is loaded only once when the web server is started. For the CGI and CLI version, it happens on every invocation.

This file contains a list of directives that control the way that PHP functions. You can see the online [[phpfn>ini|php.ini directives]] page for a detailed reference of those directives.

While in most cases, DokuWiki will operate "out-of-the-box" with typical distribution PHP settings, a number of configuration options has particular importance to DokuWiki.

On the other hand, always be warned that what may be a good or even suggested value for DokuWiki might in some cases break other PHP applications you also host. This is especially true when enabling directives that enhance PHP security while having other PHP applications that rely on insecure features of PHP like register_globals etc.

==== short_open_tag ====

Allow the ''<?'' tag.  Otherwise, only ''<?php'' and ''<script>'' tags are recognized.

DokuWiki will run with ''short_open_tag'' set to off.

  * Suggested: short_open_tag = Off

However, note that some [[:templates]] or [[:plugins]] might rely on this feature being set to ''On''.

==== open_basedir ====

This limits access of your PHP process to configured paths. This is meant as an additional security feature but should not be relied on. It will disable readdir caching and might significantly slow down your PHP processing. See [[:performance]] for details.

  * Suggested: open_basedir = 


==== output_buffering ====

Output buffering allows you to send header lines (including cookies) even after you send body content. DokuWiki will run with either setting.

  * Suggested: output_buffering = Off

==== output_handler ====

Redirect all the output of all scripts to a function. Setting ''output_handler'' automatically turns on ''output_buffering''. 

This setting can be used to automatically gzip all content before sending it to the client's browser. This can create problems with images and downloads. Turn on DokuWiki's [[config:gzip_output]] feature instead.

  * Suggested: output_handler =


==== zlib.output_compression ====

Provides transparent output compression using the zlib library. In general setting ''zlib.output_compression = On'' works quite well with DokuWiki. 

However, DokuWiki supports output compression via the [[config:gzip_output|gzip_output]] option.

  * Suggested: zlib.output_compression = Off

==== implicit_flush ====

Tells PHP to tell the output layer to flush itself automatically after every output block. Turning this option on has serious performance implications and is generally recommended for debugging purposes only. DokuWiki takes care of flushing the buffer when needed.

  * Suggested: implicit_flush = Off

==== allow_call_time_pass_reference ====

Whether to warn when arguments are passed by reference at function call time, as this method is deprecated. Arguments that should be passed by reference should be indicated in the function declaration, not at function call time.

  * Suggested: allow_call_time_pass_reference = Off

==== max_execution_time ====

Maximum execution time of each script, in seconds.

  * Suggested: max_execution_time = 30

==== max_input_time ==== 

Maximum amount of time each script may spend parsing request data.

  * Suggested: max_input_time = 60

==== max_input_vars ====

Under certain conditions (e.g.- working with large tables with the edittable plugin) the default value of 1000 is quickly met.

  * Suggested: max_input_vars = 10000

==== memory_limit ==== 

Maximum amount of memory a script may consume.

  * Suggested: memory_limit = 128M

====  error_reporting ==== 

Which errors to report.

  * Suggested: error_reporting = E_ALL & ~E_NOTICE

==== display_errors ==== 

Print out errors (as a part of the output). For production web sites, you're strongly encouraged to turn this feature off, and use error logging instead.

  * Suggested: display_errors = Off

==== display_startup_errors ====

Print out errors that occur during PHP's startup sequence (''display_errors'' has no control over these).
It's strongly recommended to keep display_startup_errors off, except for when debugging.

  * Suggested: display_startup_errors = Off

==== log_errors ====

Log errors into a log file. Also set ''error_log'' accordingly.

  * Suggested: log_errors = On


==== variables_order ====

The order in which PHP registers GET, POST, Cookie, Environment and Built-in variables (G, P, C, E & S respectively).

  * Suggested: variables_order = "EGPCS"


==== register_argc_argv ====

Whether to declare the ''argv'' & ''argc'' variables (that would contain the GET information).

  * Suggested: register_argc_argv = Off


==== file_uploads ====

Whether to allow HTTP file uploads.

  * Suggested: file_uploads = On

==== upload_max_filesize ====

Maximum allowed size for uploaded files. It should match what you expect the maximum size of uploaded mediafiles to be.

==== session.use_cookies ====

Whether to use cookies.

  * Suggested: session.use_cookies = 1

==== session.cache_limiter ====

Defines which cache control HTTP headers are sent to the client. These headers determine the rules by which the page content may be cached by the client and intermediate proxies. Acceptable values are ''none'', ''nocache'' (the default), ''private'', ''private_no_expire'' or ''public''.Setting the cache limiter to ''nocache'' disallows any client/proxy caching. A value of ''public'' permits caching by proxies and the client, whereas ''private'' disallows caching by proxies and permits the client to cache the contents. In private mode, the Expire header sent to the client may cause confusion for some browsers, including Mozilla. You can avoid this problem by using ''private_no_expire'' mode. The expire header is never sent to the client in this mode. 

In case of caching problems (i.e. you edit a page but the changes do not appear when viewing that page) you can try setting: session.cache_limiter = nocache


==== extension ====

Dynamic Extensions. See [[#PHP extensions]] above for recommendations.