Extension:Scribunto

This extension comes with MediaWiki 1.34 and above. Thus you do not have to download it again. However, you still need to follow the other instructions provided.
This extension runs on top of an executable. You must have permission to run executables on your host in order for this extension to work.
MediaWiki extensions manual
Scribunto
Release status: stable
Implementation Parser extension
Description Provides a framework for embedding scripting languages into MediaWiki pages
Author(s)
  • Victor Vasiliev
  • Tim Starling
and others
Latest version Continuous updates
Compatibility policy Snapshots releases along with MediaWiki. Master is not backward compatible.
MediaWiki >= 1.42
PHP 5.5+
License GPL-2.0-or-later AND MIT
Download
Module (ns:828), Talk_Module (ns:829)
  • $wgScribuntoDefaultEngine
  • $wgScribuntoSlowFunctionThreshold
  • $wgScribuntoGatherFunctionStats
  • $wgScribuntoUseGeSHi
  • $wgScribuntoUseCodeEditor
  • $wgScribuntoEngineConf
Quarterly downloads 547 (Ranked 8th)
Public wikis using 8,789 (Ranked 30th)
Translate the Scribunto extension if it is available at translatewiki.net
Vagrant role scribunto
Issues Open tasks · Report a bug

The Scribunto (Latin: "they shall write/let them write (in the future)") extension allows for embedding scripting languages in MediaWiki.

Currently the only supported scripting language is Lua. Scribunto Lua scripts go in a namespace called Module. Modules are run on normal wiki pages using the #invoke parser function and each module has a collection of functions, which can be called using wikitext syntax such as:

{{#invoke: Module_name | function_name | arg1 | arg2 | arg3 ... }}

License edit

This extension contains code licensed GNU General Public License v2.0 or later (GPL-2.0+) as well as code licensed MIT License (MIT).

Requirements edit

PCRE version compatibility edit

PCRE 8.33+ is recommended. PCRE 8.33 was released in May 2013. You can see the version of PCRE used by PHP by viewing a phpinfo() web page, or from the command line with the following command:

php -r 'echo "pcre: " . ( extension_loaded( "pcre" ) ? PCRE_VERSION : "no" ) . "\n";'

CentOS 6 and RHEL 6 are stuck on PCRE 7 and need to be upgraded.

Updating to 8.33 on a server with an older version may be relatively complicated. See Updating to PCRE 8.33 or Higher for details.

PHP pcntl (LTS) edit

MediaWiki versions:
1.25 – 1.28

Scribunto versions for MediaWiki 1.25 to 1.28 required PHP's pcntl extension, which is only available on Unix/Linux platforms, if you want to use "LuaStandalone" (i.e. running in a separate child process). This requirement was removed in Scribunto for MediaWiki 1.29.

You can check whether pcntl support is enabled by viewing a phpinfo() web page, or from the command line with the following command:

php -r 'echo "pcntl: " . ( extension_loaded( "pcntl" ) ? "yes" : "no" ) . "\n";'

PHP mbstring extension edit

PHP needs to have the mbstring extension enabled.

You can check whether mbstring support is enabled by viewing a phpinfo() web page, or from the command line with the following command:

php -r 'echo "mbstring: " . ( extension_loaded( "mbstring" ) ? "yes" : "no" ) . "\n";'

Lua binary edit

Bundled binaries edit

Scribunto comes bundled with Lua binary distributions for Linux (x86 and x86-64), Mac OS X Lion, and Windows (32- and 64-bit).

Scribunto should work for you out of the box if:

  1. Your web server is run on one of the above platforms.
  2. PHP's proc_open function is not restricted.[1]
  3. proc_terminate and shell_exec are not disabled in PHP.
  4. Your web server is configured to allow the execution of binary files in the MediaWiki tree.
  Note: Execute permissions may need to be set; for example, in Linux use:
chmod 755 /path/to/extensions/Scribunto/includes/Engines/LuaStandalone/binaries/lua5_1_5_linux_64_generic/lua
If you are using SELinux in "Enforcing" mode on your server, you might need to set a proper context for the binaries. Example for RHEL/CentOS 7:
chcon -t httpd_sys_script_exec_t /path/to/extensions/Scribunto/includes/Engines/LuaStandalone/binaries/lua5_1_5_linux_64_generic/lua

P.S. Check your version of the extension to see if the name of the engines folder is capitalised or fully lowercase.[2]

Additional binaries edit

Additional Lua binary distributions, which may be needed for your web server if its operating system is not in the list above, can be obtained from http://luabinaries.sourceforge.net/ or from your Linux distribution.

Only binary files for Lua 5.1.x are supported.

Once you've installed the appropriate binary file on your web server, configure the location of the file with:

# Where Lua is the name of the binary file
# e.g. SourceForge LuaBinaries 5.1.5 - Release 2 name the binary file lua5.1
$wgScribuntoEngineConf['luastandalone']['luaPath'] = '/path/to/binaries/lua5.1';

Note that you should not add the above line unless you've confirmed that Scribunto's built-in binaries don't work for you.

LuaJIT, although theoretically compatible, is not supported.

The support was removed due to Spectre and bitrot concerns (phab:T184156).

Installation edit

  • Download and move the extracted Scribunto folder to your extensions/ directory.
    Developers and code contributors should install the extension from Git instead, using:cd extensions/
    git clone https://gerrit.wikimedia.org/r/mediawiki/extensions/Scribunto
  • Add the following code at the bottom of your LocalSettings.php file:
    wfLoadExtension( 'Scribunto' );
    $wgScribuntoDefaultEngine = 'luastandalone';
    
  • Set execute permissions for the Lua binaries bundled with this extension:
chmod a+x /path/to/extensions/Scribunto/includes/Engines/LuaStandalone/binaries/yourOS/lua

[2]

  • Set type to httpd_sys_script_exec_t if SELinux is enforced:
chcon -t httpd_sys_script_exec_t /path/to/extensions/Scribunto/includes/Engines/LuaStandalone/binaries/yourOS/lua

[2]

  •   Done – Navigate to Special:Version on your wiki to verify that the extension is successfully installed.


Vagrant installation:

  • If using Vagrant , install with vagrant roles enable scribunto --provision


Optional installation edit

Integrating extensions edit

For a more pleasant user interface, with syntax highlighting and a code editor with autoindent, install the following extensions:

MediaWiki version:
1.30

Then in your LocalSettings.php after all the extension registrations, add:

$wgScribuntoUseGeSHi = true;
$wgScribuntoUseCodeEditor = true;

LuaSandbox edit

We have developed a PHP extension written in C called LuaSandbox. It can be used as an alternative to the standalone binary, and will provide improved performance. See LuaSandbox for details and installation instructions.

If you initially installed the extension to use the Lua standalone binary, be sure to update LocalSettings.php with the following configuration setting:

$wgScribuntoDefaultEngine = 'luasandbox';

Configuration edit

The following configuration variables are available:

$wgScribuntoDefaultEngine
Select the engine. Valid values are the keys in $wgScribuntoEngineConf, which by default are 'luasandbox' or 'luastandalone'.
$wgScribuntoUseGeSHi
When Extension:SyntaxHighlight is installed, set this true to use it when displaying Module pages. (MediaWiki 1.30 or earlier.)
$wgScribuntoUseCodeEditor
When Extension:CodeEditor is installed, set this true to use it when editing Module pages. (MediaWiki 1.30 or earlier.)
$wgScribuntoEngineConf
An associative array for engine configuration. Keys are the valid values for $wgScribuntoDefaultEngine, and values are associative arrays of configuration data. Each configuration array must contain a 'class' key naming the ScribuntoEngineBase subclass to use.

LuaStandalone edit

The following keys are used in $wgScribuntoEngineConf for Scribunto_LuaStandaloneEngine. Generally you'd set these as something like

$wgScribuntoEngineConf['luastandalone']['key'] = 'value';
luaPath
Specify the path to a Lua interpreter.
errorFile
Specify the path to a file, writable by the web server user, where the error and debugging output from the standalone interpreter will be logged.
Error output produced by the standalone interpreter are not logged by default. Configure logging with:
$wgScribuntoEngineConf['luastandalone']['errorFile'] = '/path/to/file.log';
memoryLimit
Specify the memory limit in bytes for the standalone interpreter on Linux (enforced using ulimit).
cpuLimit
Specify the CPU time limit in seconds for the standalone interpreter on Linux (enforced using ulimit).
allowEnvFuncs
Set true to allow use of setfenv and getfenv in modules.

LuaSandbox edit

The following keys are used in $wgScribuntoEngineConf for Scribunto_LuaSandboxEngine. Generally you'd set these as something like

$wgScribuntoEngineConf['luasandbox']['key'] = 'value';
memoryLimit
Specify the memory limit in bytes.
cpuLimit
Specify the CPU time limit in seconds.
profilerPeriod
Specify the time between polls in sections for the Lua profiler.
allowEnvFuncs
Set true to allow use of setfenv and getfenv in modules.

Usage edit

Scripts go in a new namespace called Module. Each module has a collection of functions, which can be called using wikitext syntax such as:

{{#invoke: Module_name | function_name | arg1 | arg2 | arg3 ... }}

Lua edit

Learning Lua edit

Lua is a simple programming language intended to be accessible to beginners. For a quick crash-course on Lua, try Learn Lua in 15 Minutes.

The best comprehensive introduction to Lua is the book Programming in Lua. The first edition (for Lua 5.0) is available online and is mostly relevant to Lua 5.1, the version used by Scribunto:

The reference manual is also useful:

Lua environment edit

In Lua, the set of all global variables and functions is called an environment.

Each {{#invoke:}} call runs in a separate environment. Variables defined in one {{#invoke:}} will not be available from another. This restriction was necessary to maintain flexibility in the wikitext parser implementation.

The environment which scripts run in is not quite the same as in standard Lua. These differences are noted in Extension:Scribunto/Lua reference manual.

Debug console edit

 
Debug console usage example
See also: Extension:Scribunto/Debug console

When editing a Lua module a so-called "debug console" can be found underneath the edit form. In this debug console Lua code can be executed without having to save or even create the Lua module in question.

Troubleshooting edit

 
Troubleshooting using the clickable "Script error" link.

Note that red Script error messages are clickable and will provide more detailed information.

Lua error: Internal error: The interpreter exited with status 1. edit

When using the LuaStandalone engine (this is the default), errors along the lines of "Lua error: Internal error: The interpreter exited with status 1." may be generated if the standalone Lua interpreter cannot be executed or runs into various runtime errors. To obtain more information, assign a file path to $wgScribuntoEngineConf['luastandalone']['errorFile']. The interpreter's error output will be logged to the specified file, which should prove more helpful in tracking down the issue. The information in the debug log includes debugging information, which is why there is so much of it. You should be able to ignore any line beginning with "TX" or "RX".

If you're setting up Scribunto and are using IIS/Windows, this appears to be solved by commenting out a particular line.

Lua error: Internal error: The interpreter exited with status 2. edit

When using the LuaStandalone engine (this is the default), status 2 suggests memory allocation errors, probably caused by settings that allocate inadequate memory space for PHP or Lua, or both. Assigning a file path to $wgScribuntoEngineConf['luastandalone']['errorFile'] and examining that output can be valuable in diagnosing memory allocation errors.

Increase PHP allocation in your PHP configuration; add the line memory_limit = 200M. This allocation of 200MB is often sufficient (as of MediaWiki 1.24) but can be increased as required. Set Scribunto's memory allocation in LocalSettings.php as a line:

$wgScribuntoEngineConf['luastandalone']['memoryLimit'] = 209715200; # bytes

Finally, depending on the server configuration, some installations may be helped by adding another LocalSettings.php line

$wgMaxShellMemory = 204800; # in KB

Note that all 3 memory limits are given in different units.

Lua error: Internal error: 2. on ARM architecture edit

If you're using an ARM architecture processor like on a RaspberryPi you'll face the error Lua error: Internal error: The interpreter exited with status 2. due to wrong delivered binary format of the Lua interpreter.

Check your Lua interpreter in:

/path/to/webdir/Scribunto/includes/Engines/LuaStandalone/binaries/lua5_1_5_linux_32_generic

Check the interpreter by using:

file lua 

The result should look like :

lua: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-armhf.so.3, for GNU/Linux 3.2.0

The installed default Lua interpreter shows:

lua: ELF 32-bit LSB pie executable, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.9,

look at the "Intel 80386" part what definitely is not correct.

Check in /usr/bin what version of Lua is installed on your system. If you have lua5.1 installed, you can either copy the interpreter to your lua5_1_5_linux_32_generic directory or set in your LocalSettings.php:

$wgScribuntoEngineConf['luastandalone']['luaPath'] = '/usr/bin/lua5.1';

At present don't set wgScribuntoEngineConf to /usr/bin/lua5.3, it'll lead to the "Internal error 1".

Lua error: Internal error: The interpreter exited with status 24. edit

When using the LuaStandalone engine (this is the default), status 24 suggests CPU time limit errors, although those should be generating a "The time allocated for running scripts has expired" message instead. It would be useful to file a task in Phabricator and participate in determining why the XCPU signal isn't being caught.

Lua error: Internal error: The interpreter exited with status 126. edit

When using the LuaStandalone engine (this is the default), errors along the lines of "Lua error: Internal error: The interpreter exited with status 126." may be generated if the standalone Lua interpreter cannot be executed. This generally arises from either of two causes:

  • The Lua executable file's permissions do not include Execute. Set permissions as described under #Installation.
  • The server does not allow execution of files from the place where the executable is installed, e.g. the filesystem is mounted with the 'noexec' flag. This often occurs with shared hosted servers. Remedies include adjusting $wgScribuntoEngineConf['luastandalone']['luaPath'] to point to a Lua 5.1 binary installed in an executable location, or adjusting or convincing the shared host to adjust the setting preventing execution.

Error condition such as: Fatal exception of type MWException edit

Check the MediaWiki, PHP, or webserver logs for more details on the exception, or temporarily set $wgShowExceptionDetails to true.

version 'GLIBC_2.11' not found edit

If the above gives you errors such as "version 'GLIBC_2.11' not found", it means the version of the standard C library on your system is too old for the binaries provided with Scribunto. You should upgrade your C library, or use a version of Lua 5.1 compiled for the C library you do have installed. To upgrade your C library, your best option is usually to follow your distribution's instructions for upgrading packages (or for upgrading to a new release of the distribution, if applicable).

If you copy the lua binaries from Scribunto master (or from gerrit:77905), that should suffice, if you can't or don't want to upgrade your C library. The distributed binaries were recently recompiled against an older version of glibc, so the minimum is now 2.3 rather than 2.11.

Lua errors in Scribunto files edit

Errors here include:

  • attempt to index field 'text' (a nil value)
  • Lua error in mw.html.lua at line 253: Invalid class given:

If you are getting errors such these when attempting to use modules imported from WMF wikis, most likely your version of Scribunto is out of date.

Upgrade if possible; for advanced users, you might also try to identify the needed newer commits and cherry-pick them into your local installation.

preg_replace_callback(): Compilation failed: unknown property name after \P or \p at offset 7 edit

preg_replace_callback(): Compilation failed: unknown property name after \P or \p at offset 7

  • this usually indicates an incompatible version of PCRE; you'll need to update to >= 8.10
  • @todo: link to instructions on how to upgrade

Lua error edit

If you copy templates from Wikipedia and then get big red "Lua error: x" messages where the Scribunto invocation (e.g. the template that uses {{#invoke:}}) should be, that probably means that you didn't import everything you needed. Make sure that you tick the "Include templates" box at w:Special:Export when you export.

When importing pages from another wiki, it is also possible for templates or modules in the imported data to overwrite existing templates or modules with the same title, which may break existing pages, templates, and modules that depend on the overwritten versions.

Blank screen edit

Make sure your extension version is applicable to your MediaWiki version.

Design documents edit

Other pages edit

See also edit

General
  • Lua Wikibase client - functionality for the Scribunto extension.
  • Commons:Lua - there may be specific notes for using Lua modules on Wikimedia Commons, including additional Lua extensions installed (e.g. for local support of internationalization and for parsing or playing medias). Some general purpose modules may be reused in other wikis in various languages (except specific tunings for policies, namespaces or project/maintenance pages with dedicated names). If possible, modules that could be widely reused across wikis should be tested and internationalized on Wikimedia Commons.
  • w:Help:Lua - there may be specific notes for using Lua modules on Wikipedia, including additional Lua extensions installed (including for integrating Wikidata and Wikimedia Commons contents, generating complex infoboxes and navigation boxes, or to facilitate the general administration/maintenance of the wiki contents under applicable policies). Some other localized Wikipedia editions (or other projects such Wiktionnary, Wikisource or Wikinews) may also have their own needs and Lua modules.
  • d:Help:Lua - there may be specific notes for using Lua modules on Wikidata, including additional Lua extensions installed (e.g. for local support of internationalization and for database queries)
Extensions

External links edit

Notes edit

  1. i.e. Scribunto will not work if proc_open is listed in the disable_functions array in your server's "php.ini" file. If it is, you may see an error message like proc_open(): open_basedir restriction in effect. File(/dev/null) is not within the allowed path(s):. If you are using Plesk and have been granted sufficient permissions, you may be able to set open_basedir in the PHP settings for your domain or subdomain. Try changing {WEBSPACEROOT}{/}{:}{TMP}{/} to {WEBSPACEROOT}{/}{:}{TMP}{/}{:}/dev/null{:}/bin/bash.
  2. 2.0 2.1 2.2 The name of the engines folder changed from lowercase to capitalised in 2022.