Extension:Scribunto

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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.[[Category:extensions bundled with MediaWiki 1.34{{#translation:}}]]

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[[Category:All extensions{{#translation:}}]]

<translate>
The **Scribunto** (Latin: "*they shall write/let them write (in the future)*") extension allows for embedding scripting languages in MediaWiki.</translate>
<translate>
Currently the only supported scripting language is Lua.
</translate>

<translate>

## License

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

### PCRE version compatibility

PCRE 8.33+ is recommended.</translate>
<translate>
You can see the version of PCRE used by PHP by viewing a phpinfo() web page, or from the command line with the command <tvar|1>`php -r 'echo "pcre: " . ( extension_loaded( "pcre" ) ? PCRE_VERSION : "no" ) . "\n";'`</>.

* Scribunto will not work with versions of PCRE lower than 8.10.</translate>

<translate>

* PCRE 8.31 has bugs with JIT pattern studying that [[<tvar|1>phab:T73922</>|breaks various patterns when used with HHVM]].</translate>

<translate>

* PCRE 8.32 has [<tvar|url>https://bugs.exim.org/show\_bug.cgi?id=1340</> a bug] that will cause it to reject certain non-character codepoints, which will cause errors in the mw.html module.

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.</translate>
<translate>
See Updating to PCRE 8.33 or Higher for details.

### PHP pcntl (LTS)

</translate>

<translate>
Scribunto versions for MediaWiki 1.25 to 1.28 required PHP's [<tvar|url>https://secure.php.net/pcntl.installation</> pcntl extension], which is only available on Unix/Linux platforms, if you want to use "LuaStandalone" (i.e. running in a separate child process).</translate>
<translate>
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 command <tvar|1>`php -r 'echo "pcntl: " . ( extension_loaded( "pcntl" ) ? "yes" : "no" ) . "\n";'`</>.
</translate>

### PHP mbstring extension

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

### Lua binary

#### Bundled binaries

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
3. Your web server is configured to allow the execution of binary files in the MediaWiki tree.

Note **Note:** Execute permissions may need to be set; for example, in Linux use

```
chmod a+x /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

```

#### Additional binaries

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:

```
# 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.

## Installation

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

Manual installation
* Download and place the file(s) in a directory called `Extension:Scribunto` in your `extensions/` folder.

* Add the following code at the bottom of your LocalSettings.php:
```
wfLoadExtension( 'Extension: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

```

* 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

```

* File:Yes check.svg **Done** – Navigate to Special:Version on your wiki to verify that the extension is successfully installed.

To users running MediaWiki 1.29 or earlier:

The instructions above describe the new way of installing this extension using `wfLoadExtension()`. If you need to install this extension on these earlier versions (MediaWiki 1.29 and earlier), instead of `wfLoadExtension( 'Extension:Scribunto' );`, you need to use:

```
require\_once "$IP/extensions/Extension:Scribunto/Extension:Scribunto.php";

```

## Optional Installation

### Integrating extensions

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

* Extension:WikiEditor
* Extension:SyntaxHighlight
* Extension:CodeEditor

(MediaWiki 1.30 or earlier)Then in your LocalSettings.php after all the extension registrations, add:

```
$wgScribuntoUseGeSHi = true;
$wgScribuntoUseCodeEditor = true;

```

<translate>

### LuaSandbox

We have developed a PHP extension written in C called LuaSandbox.</translate>
<translate>
It can be used as an alternative to the standalone binary, and will provide improved performance.</translate>
<translate>
See <tvar|1>LuaSandbox </> for details and installation instructions.

If you initially installed the extension to use the Lua standalone binary, be sure to update <tvar|1>LocalSettings.php</> with <tvar|2>`$wgScribuntoDefaultEngine = 'luasandbox';`</>.

## Configuration

The following configuration variables are available:
</translate>

$wgScribuntoDefaultEngine
<translate> Select the engine.</translate> <translate> Valid values are the keys in <tvar|1>$wgScribuntoEngineConf</>, which by default are <tvar|2>'luasandbox'</> or <tvar|3>'luastandalone'</>.</translate>
$wgScribuntoUseGeSHi
<translate> When <tvar|1>Extension:SyntaxHighlight </> is installed, set this true to use it when displaying Module pages.</translate>
$wgScribuntoUseCodeEditor
<translate> When <tvar|1>Extension:CodeEditor </> is installed, set this true to use it when editing Module pages.</translate>
$wgScribuntoEngineConf
<translate> An associative array for engine configuration.</translate> <translate> Keys are the valid values for <tvar|1>$wgScribuntoDefaultEngine</>, and values are associative arrays of configuration data.</translate> <translate> Each configuration array must contain a <tvar|1>'class'</> key naming the <tvar|2>ScribuntoEngineBase</> subclass to use.</translate>
<translate>

### LuaStandalone

The following keys are used in <tvar|1>$wgScribuntoEngineConf</> for <tvar|2>Scribunto\_LuaStandaloneEngine</>.</translate>
<translate>
Generally you'd set these as something like
</translate>

```
$wgScribuntoEngineConf['luastandalone']['key'] = 'value';

```

luaPath
<translate> Specify the path to a Lua interpreter.</translate>
errorFile

<translate> 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.</translate>
<translate> Error output produced by the standalone interpreter are not logged by default.</translate> <translate> Configure logging with:</translate>
```
$wgScribuntoEngineConf['luastandalone']['errorFile'] = '/path/to/file.log';

```

memoryLimit
<translate> Specify the memory limit in bytes for the standalone interpreter on Linux (enforced using ulimit).</translate>
cpuLimit
<translate> Specify the CPU time limit in seconds for the standalone interpreter on Linux (enforced using ulimit).</translate>
allowEnvFuncs
<translate> Set true to allow use of setfenv and getfenv in modules.</translate>
<translate>

### LuaSandbox

The following keys are used in <tvar|1>$wgScribuntoEngineConf</> for <tvar|2>Scribunto\_LuaSandboxEngine</>.</translate>
<translate>
Generally you'd set these as something like
</translate>

```
$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

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

```

```

## Lua

### Learning Lua

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:

* Programming in Lua (scroll down past the book ads to find the text)

The reference manual is also useful:

* Lua reference manual

### Lua environment

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.

<templatestyles src="Note/styles.css" />

The environment which scripts run in is not quite the same as in standard Lua. These differences are noted in Special:MyLanguage/Extension:Scribunto/Lua reference manual#Differences from standard Lua.
### Debug console

 File:Scribunto debug console usage example.png
*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

 File:Script error clickable Scribunto.png
Note that red **Lua error** messages are clickable and will provide more detailed information.

### Lua error: Internal error: The interpreter exited with status 1

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".

### Lua error: Internal error: The interpreter exited with status 2

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: The interpreter exited with status 24

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

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 2 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

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

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

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

`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

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

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

## Design documents

* File:Linux.conf.au 2014 - Scribunto presentation.webm  Extension:Scribunto/Parser interface design
* Extension:Scribunto/Victor's API proposal
* Extension:Scribunto/Documentation specification
* Extension:Scribunto/Tim's draft roadmap

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## Other pages

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* Extension:Scribunto/Deployment priorities
* Extension:Scribunto/Brainstorming
* Lua scripting  - Wikimedia activity page describing deployment plan to Wikimedia sites
* Extension:Scribunto/Lua reference manual  - The reference about the Lua language, as well as its standard libraries and common Scribunto modules supported on Wikimedia sites
* Extension:Scribunto/Lua 5.2 changes  - A list of known changes in Lua 5.2 that may cause code written in 5.1 to function unexpectedly
* Extension:Scribunto/Example modules
* Extension:Scribunto/Example extension  - Code for example extensions extending the Scribunto library.
* Extension:Scribunto/We use Lua

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## See also

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General
* Lua Wikibase client functionality for the Scribunto extension.
* commons: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 Commons.
* wikipedia:Help:Lua - there may be specific notes for using Lua modules on (English) 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.
* wikidata: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
* Capiunto - Provides basic Infobox functionality for the Scribunto extension.
* Semantic Scribunto - provides native support for the Scribunto extension for usage with Extension:Semantic MediaWiki
* VariablesLua - provides a Scribunto Lua interface for the Variables extension
* Wikibase Client - Provides Wikibase (part of Wikidata project)

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## Notes

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1. ↑ i.e. `proc_open` is not within the array of `disable_functions` in your server's "php.ini" file.

[[Category:Skins used on Wikimedia{{#translation:}}|Extension:Scribunto]]

[[Category:Scribunto extensions{{#translation:}}| ]]
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