User:Xephyr826/Manual:Special pages

Special pages are pages that are created by the software on demand to perform a specific function. For example, a special page might show all pages that have one or more links to an external site or it might create a form providing user submitted feedback. Special pages are located in their own  (Special:) and are not editable directly like other pages. s can also create new special pages. These pages can be user-accessible and will generally show up in the list of all special pages at Special:SpecialPages. Some special pages are only accessible to users with certain permissions and accesses. Other special pages don't show up on the special page list at all and are only used by the wiki internally.

General Information
All of the ~75 built-in special pages that come with MediaWiki are called   and are located in the   directory. Special pages created by third party developers are generally stored in the   directory in their own file or as part of a larger extension. All special pages inherit from a class called SpecialPage which is defined in  . When a new special page is created, the user rights needed to access the page can be defined. These rights specify, among other things, whether the page will show up on Special:SpecialPages and whether the page is includable in other pages.

Special pages also have unique names that can be customized on a wiki. The general form is "Special:Pagename" where both "Special" and "Pagename" are customizable. The Special pseudo <tvar|manual></> can be translated in other languages. This translated namespace can be produced with the wikitext <tvar|nsspecial>     </>, on this wiki giving "    ". The name of the special page can also be redefined in a system message, for the site language, with the generic name of the special page as the ID.

A special page may or may not allow input. For example, <tvar|Export>Special:Export</> allows a user to define a specific page to export by calling <tvar|exportsun>Special:Export/Sun</>. If the special page allows complex input, additional parameters will be sent to the query string component of the the URL for processing, e.g. http://www.mediawiki.org/w/index.php?title=Special:Recentchanges&days=3&limit=250.


 * There are various ways to make special1>Special:MyLanguage/Help:Special pages</>|special pages, but the one below is used by the bulk of official <tvar|man></>, and adherence to this style is recommended. Also, be sure to include a credits block in the new special page for 'specialpage'. See <tvar|ExtensionCredits><tt></tt></> for more details.
 * After making a new special page, be sure to add it to SpecialPageExtensions>Special:MyLanguage/:Category:Special page extensions</> so other people can find it.
 * This method is only valid for MediaWiki running on PHP5 and above. If you're using an earlier version of MediaWiki on a more-recent version of PHP, <tvar|upgrade></>.
 * Special pages cannot be included within frames unless you use $wgOut->allowClickjacking;

Basic special page template
Most special page extensions require three files: a small setup file, which will be loaded every time MediaWiki starts, a localisation file, and a file with the bulk of the code. All of them should be placed in a new directory inside the MediaWiki <tvar|extens><tt>extensions/</tt></> directory. MediaWiki coding conventions define the four files like this:


 * - The setup file.
 * - The special page code.
 * - The <tvar|localisation></>.

Generally the special page should be named after the extension: so the gadgets>Special:MyLanguage/Extension:Gadgets</>|Gadgets extension has the file <tvar|SpecialGadgetscode> </>. If your extension has more than one special page, you'll need more names.

In the example below, the special page's name is MyExtension.

After creating the files listed below, add the following line to LocalSettings.php

The setup file
The setup file <tt>MyExtension/extension.json</tt> looks like this:

This file registers several important things (all mandatory):


 * The location of the SpecialMyExtension class
 * The location of localisation files
 * The new special page and its class name

The special page file
The body file <tvar|php> </>) should contain a subclass of SpecialPage or one of its subclasses. It will be loaded automatically when the special page is requested. This example implements the subclass SpecialMyExtension:

You need the <tvar|conduct> </> constructor because its first parameter names your special page.

<tvar|execute> </> is the main function that is called when a special page is accessed. The function overloads the function <tvar|SpecialPage> </>. It passes a single parameter <tvar|par> </>, the subpage component of the current title. For example, if someone follows a link to <tvar|blah>Special:MyExtension/blah</>, <tvar|par1> </> will contain "blah".

Wikitext and HTML output should normally be run via $wgOut — do not use 'print' or 'echo' directly when working within the wiki's user interface.

However if you're using your special page as an access point to custom XML or binary output, see <tvar|takingoveroutput></>.

The localisation file

 *  See <tvar|1></> for how to get them translated. 

All special pages have a title specified, like <tvar|Myextension><tt>'My Extension'</tt></>.


 * It's used in the <tvar|title><tt> </tt></> and <tvar|H1><tt> <H1> </tt></> elements of the extension's page and on <tvar|SpecialPages>Special:SpecialPages</>.
 * It can be anything, but should describe the special page and extension.
 * It's specified through a message. The structure of the message is a key-value pair. The key, <tvar|myext><tt>'myextension'</tt></>, must be in all lowercase.

An example of a localisation file in <tvar|i18n> </>:

And in in <tvar|qqq> </> the msgdoc>Special:MyLangauage/Localisation#Message documentation</>|message documentation:

Note that IDs should not start with an uppercase letter, and that a space in the ID should be written in the code as an underscore.

The -summary message is optional. It's created automatically by the parent class and shown on top of the special page, usually for a concise description of what the user can do on it. If you don't define its content, it will only be used when wiki administrators customize it on the wiki for their own purposes.

Special page group
You can set which group your special page is categorized under on <tvar|special>Special:SpecialPages</> by overriding SpecialPage::getGroupName in your subclass.

</> system interface message, which translates to 'Media reports and uploads' in English; *     * @return string */   function getGroupName { return 'media'; }

Some common values are 'login', 'maintenance', 'media', 'other', 'pagetools', 'redirects', 'users'. You can see the accepted values at <tvar|AllMessages> Special:AllMessages </> (search for specialpages-group) or browse the wiki using the pseudo language 'qqx' (ie. go to <tvar|uselang> Special:SpecialPages?uselang=qqx </>) and look at the headings. Specify the word 'media' to use the interface message 'specialpages-group-media'

If your special page doesn't seem to fit into any of the preconfigured headings, you can add a new heading by adding it to your localisation file (see <tvar|TheLocalisationFile></>)

The standard page groups that come with MediaWiki are listed in the localisation file (for example, the English messages are in <tvar|json> </>) and begin with <tvar|specialpagesgroup> </>. If your special page is to be categorized under, for example, <tvar|users> </>, then the message looked for is <tvar|msg> </>. The value for this key is the text that appears as the name of that category, for example,.

If your special page does not seem to fit under any of the existing categories, you can always make a new one. In your extension's localisation file simply insert a new key for the <tvar|messages> </> array. In this example, we will define the <tvar|gamification> </> group:

Now, assuming you have already set the return value for the method SpecialPage::getGroupName in your class definition and reload <tvar|special>Special:SpecialPages</> to see your new category.

Constructor
You can overload the constructor to initialize your own data, but the main reason you would want to do it is to change the behavior of the SpecialPage class itself. When you call the base class constructor from your child class, the following parameters are available:


 * string  Name of the special page, as seen in links and URLs
 * string  userright>Special:MyLangauge/Manual:User rights</>|User right required, e.g. "block" or "delete"; also see Restrictingpageaccess>Special:MyLanguage/Manual:Special_pages#Restricting_page_access</>|Restricting page access
 * boolean  Whether the page is listed in Special:Specialpages

This initialises the OutputPage object <tvar|wgout> </> with the name and description of your special page. It should always be called from your execute method.

This method returns an OutputPage object which can be accessed as described below. As in the example code, use

instead of the deprecated $wgOut global variable

This method returns a WebRequest object which can be accessed as described below. As in the example code, use

instead of the deprecated $wgRequest global variable

Some special pages can be included from within another page. For example, if you add <tvar|RecentChanges> </> to the wikitext of a page, it will insert a listing of recent changes within the existing content of the page.

Including a special page from another web page is only possible if you declared the page to be includable in the constructor. You can do this by adding the following in the <tvar|codeconstruct> </> method after the parent class initialization:

You can also define your special page class as extending the IncludableSpecialPage class.

The SpecialPage->including function returns a boolean value telling you what context the special page is being called from: false if it is a separate web page, and true if it is being included from within another web page. Usually you will want to strip down the presentation somewhat if the page is being included.

This is the function which your child class should overload. It passes a single parameter, usually referred to cryptically as <tvar|codepar> </> (short for $parameter, as it is the parameter the users can feed to your special page). This parameter is the subpage component of the current title. For example, if someone follows a link to <tvar|myextensionblah>Special:MyExtension/blah</>,  will contain "blah".

Help page
It's useful to add ProjectPD>Special:MyLanguage/Project:PD help</>|help pages on MediaWiki.org, where they'll be ProjectLanguagePolicy>Special:MyLanguage/Project:Language policy</>|translatable. To make sure users find your help page, it's advisable and very simple for your special page to link the help page in question:

OutputPage.php
OutputPage.php contains the class definition for objects of type <tvar|OutputPage> </>). You can get an object of this class from your SpecialPage using

The variablename $output is, of course, arbitrary. Whatever you call it, this is the variable you will use the most, because it is the way to send output to the browser (no, you don't use <tvar|codeecho> </> or <tvar|print> </>). If you want to use it somewhere, declare the variable global:

If you want to, you can create multiple OutputPage objects in different methods in your SpecialPage extension. They will add to the output in the order they are executed.

You can inspect the OutputPage class by viewing <tvar|ManOutputPage> </> (indeed, all of these can be inspected), but there are a few methods you should definitely know about.

Essentially the quick and dirty substitute for <tvar|echo> </>. It takes your input and adds it to the buffer: no questions asked. In the below action, if <tvar|action> </> contains user-data, it could easily have XSS, evil stuff, or the spawn of Satan injected in. You're better off using escaping (such as with the php function htmlentities) or the XML builders class to build trusted output.

For most output, you should be using this function. It's a bit of a black magic function: wikitext goes in, HTML comes out, and a whole lotta arcane code and demon summonings happen in between.

What's worth noting is that the parser will view your chunks as cohesive wholes and paragraph accordingly. That is...

Will output three lists with one item each, which probably wasn't intended.

Note however, if you just want to insert a system message and have it treated like parsed wikitext, you can use code like <tvar|getOutput> </>. This will not have the issue with nested parser calls mentioned above.

workaround #1
Important: these work arounds are only needed if you are making a transcludable special page. Normal special pages do not need these

As a workaround, you can have your extensions convert Wikitext to HTML using a separate Parser object and then use <tvar|addHTML> .</> Example:

workaround #2
I tried the above, and found that the same problem now applied to any <tvar|s> s </> in the transcluded text. This won't be a problem for a lot of extensions, but the extension I was writing was intended to show wikitext from another page as part of its functionality, so this was a problem.

The process for parsing a page which transcludes a special page seems to be this:
 * 1) Replace <tvar|special5>  </> with a UNIQ-QINU marker (because SpecialPage output is expected to be ready-to-output HTML)
 * 2) Replace any <tvar|s1> s </> with QINU markers as above
 * 3) Parse everything else from wikitext to HTML
 * 4) Replace all QINU markers with their respective stored values, in a single pass

The process for parsing a page which transcludes a non-special page, though, is apparently like this:
 * 1) Replace <tvar|normal></> or <tvar|templatename></> with contents of transcluded page (because transcluded pages contain unparsed wikitext)
 * 2) Replace any <tvar|s2> s </> with QINU markers as above
 * 3) Parse everything else from wikitext to HTML
 * 4) Replace all QINU markers with their respective stored values, in a single pass

The problem is apparently that in the earlier case, the parsing of the SpecialPage's wiki text is lacking the final QINU decoding step (why?), so all the QINU markers are left undecoded. (This may be a leftover from using the same syntax to invoke transclusion of a wikitext page, which is just pasted straight into the host page's wikitext contents and parsed, as is used to invoke transclusion of a SpecialPage, which must not be parsed at all. Wherever the code is that decides "wait, this is a special page -- replace it with a QINU", it should be doing the extra unstripGeneral before doing the QINU substitution.)

So I just did the following -- after this line: ...I added these lines (the second one is only because the function definition for the first one recommends it): Since I have now documented this, of course, I will now find a tragic flaw with it and feel really stupid... but as long as it seems to be working, I had to note it here. (It is also important to note the problem with work-around #1.) Also, I have only tested this with MediaWiki 1.10.1. The problem still exists under MW 1.14, but this solution may or may not work. --<tvar|woozle></> 18:26, 9 April 2009 (UTC)

In most of the real special pages, you will rarely see <tvar|codewgOut> </> without <tvar|wfMessage> </> popping in.

<tvar|wfMessage1> </> is a <tvar|MediaWiki></> <tvar|internationalization></> (i18n) function. See <tvar|MessagesAPI></>

An error page is shown. The arguments <tvar|codetitle> </> and <tvar|msg> </> specify keys into wfMessage, not text. An example:


 * 'error' refers to the text "Error".
 * 'badarticleerror' refers to the text "This action cannot be performed on this page.".

You can also specify message objects or add parameters:

WebRequest.php
The WebRequest class is used to obtain information from the GET and POST arrays. Using this is recommended over directly accessing the superglobals, since the object does fun stuff like magic_quotes cleaning. The WebRequest object is accessible from extensions by using the <tvar|RequestContext></>.

Returns a string that corresponds to the form input with the name <tvar|key> </>.

Returns an int, bool, etc depending on the function called. For checkboxes for example, the function <tvar|getBool> </> is useful.

Returns true if a form was posted.

Database.php
MediaWiki has a load of convenience functions and wrappers for interacting with the database. It also has an interesting load balancing scheme in place. It's recommended you use these wrappers. Check out <tvar|Database> </> for a complete listing of all the convenience functions, because these docs will only tell you about the non-obvious caveats. See <tvar|Databaseaccess></>.

As this name suggests, this function gets you a reference of the database. There is no global that contains a database object.

When you call the function, you should pass it a parameter, the constant <tvar|DBMASTER> </> or <tvar|DBSLAVE> </>. Generally, you interact with the slave database when you're only performing read operations, and interact with the master when you're writing to the database. It's real easy to do, so do it, even if you only have one database.

User.php
The User class is used to represent users on the system. The global <tvar|wgUser> </> represents the currently logged in user, and is usually what you will deal with when manipulating users.

Returns true or false depending on whether the user is allowed to do $right.

Returns true if a user is blocked.

Title.php
Title represents the name of a page in the wiki. This is useful because MediaWiki does all sorts of fun escaping and special case logic to page names, so instead of rolling your own convert title to URL function, you create a Title object with your page name, and then use <tvar|escapeLocalURL> </> to get a URL to that page.

To get a title object for your special page from outside of the special page class, you can use <tvar|SpecialPageYourCanonical> </>. It will give you a localised title in the wiki's language.

Custom special pages
There are various ways to provide your own special pages not bundled within MediaWiki:
 * One method is to install an extension that generates a form to create or edit an article. A list of extensions currently available, can be found at <tvar|category></>.
 * You can also write an extension which provides your own special page. Writing your own extension requires PHP coding skill and comfort with object oriented design and databases also is helpful.  You will also need to know how to use code to create and edit MediaWiki articles. For more information, please see <tvar|Articleswithembeddedforms>this discussion.
 * You can also display a custom page through Javascript, in place of the default error message "Unknown special page". In MediaWiki:Common.js, check for <tvar|wgPagename></>, then hide the MediaWiki-generated content (just appendCSS <tvar|visibility> </> ), and inject custom HTML (<tvar|innerHTML> </>) into the <tvar|bodyContent> </> or <tvar|mwcontentholder> </>. For an example, see w:en:User:Splarka/electrocute.js.

Setting an Extension Title
MediaWiki does not set the title of the extension, which is the developer's job. It will look for the name of the extension when <tvar|special>Special:Specialpages</> is called or the special page is loaded (specifically right before the registered <tvar|wfSpecial><tt>wfSpecial*</tt></> function is called). In the function execute( $par ) section, use <tvar|ttwgout><tt>$wgOut</tt></> to title the extension like: <tvar|setPageTitle><tt>$wgOut->setPageTitle("your title");</tt></>

The place where the extension can be found (as specified by what is passed into the SpecialPage constructor) is the key--except that it is not capitalized because of <tvar|getDescription> </>, the internally used function that finds out the title (or, what they call description) of the special page, <tvar|strtolower> </> the name. "ThisIsACoolSpecialPage"'s key would be "thisisacoolspecialpage."

Theoretically, <tvar|getDescription1><tt>getDescription</tt></> can be overloaded in order to avoid interacting with the message cache but, as the source code states: "Derived classes can override this, but usually it is easier to keep the default behavior. Messages can be added at run-time--see MessageCache.php". Furthermore, this prevents the MediaWiki namespace from overloading the message, as below.

Localizing the Extension Name
So you've just installed a shiny new MediaWiki extension and realize: "Oh no, my wiki is in French, but the page is showing up as English!" Most people wouldn't care, but it's actually a quite simple task to fix (as long as the developer used the method explained on this page). No noodling around in source code. Let's say the name of the page is <tvar|DirtyPages> </> and the name comes out to "List of Dirty Pages" but you want it to be (and excuse my poor French) "Liste de Pages Sales". Well, it's as simple as this:


 * 1) Navigate to <tvar|MediaWikiDirtyPages></>, this page may not exist, but edit it anyway
 * 2) Insert "Liste de Pages Sales" and save

And voilà (pardon the pun), the change is applied.

This is also useful for customizing the title for your wiki within your language: for instance, the developer called it "List of Dirty Pages" but you don't like that name, so you rename it "List of Pages needing Cleanup". Check out <tvar|Allmessages>Special:Allmessages</> to learn more.

Also, if your extension has a large block of text that does change, like a warning, don't directly output the text. Instead, add it to the message cache and when the time comes to output the text in your code, do this:

Then this message too can be customized at <tvar|Dirtypageshelp></>.

See also SystemMessage>Special:MyLanguage/Help:System message</>|Help:System message.

Do not display your SpecialPage on the <tvar|special>Special:SpecialPages</> page
Sometimes you may want to limit the visibility of your SpecialPage by removing it from the <tvar|special>Special:SpecialPages</> page and making it visible to only a set group of users. You can do this in the <tvar|constructor></> by passing in a <tvar|restriction> </> parameter; e.g., “editinterface”, a right only assigned to sysops by default; see the UserRightsManual>Special:MyLanguage/Manual:User_rights</>|User rights manual for other available user rights.

Or you can create your own right in <tvar|TheSetupFile></> and assign it to sysops, e.g.:

and then call the constructor with your right:

Do not allow url access to your SpecialPage
Even if you restrict your page in the constructor, as mentioned above, your SpecialPage will still be viewable directly via the url, e.g., Special:MySpecialPage. In order to limit access to your SpecialPage via the url, make sure the following is in your extension’s <tvar|execute> </> method.

Disabling Special:UserLogin and Special:UserLogout pages
In LocalSettings.php you can use the <tvar|Hooks></> to unset unwanted built-in special pages. See mailarchive>mailarchive:mediawiki-l/2009-June/031231.html</>|"making a few SpecialPages restricted" if you need conditional unsetting of special pages for example for certain user groups. The general message "You have requested an invalid special page." is shown if users try to access such unset special pages.

Adding logs
On MediaWiki, all actions by users on wiki are tracked for transparency and collaboration. See <tvar|log></> for how to do it.

Changing the groups on <tvar|special>Special:Specialpages</>
If you want to set the group under which "Special:MyLittlePage" is displayed on <tvar|special>Special:Specialpages</> to "MyLittleGroup", you just have to create "MediaWiki:Specialpages-specialpagegroup-mylittlepage" with content "MyLittleGroup". "Special:MyLittlePage" will then show up under the group "MyLittleGroup", which you can name under "MediaWiki:Specialpages-group-mylittlegroup".

If you want to change the the group of existing special pages, have a look on [<tvar|url1>https://www.mediawiki.org/w/index.php?title=Special:SpecialPages&uselang=qqx Special:SpecialPages&uselang=qqx</>] und use those names instead of "mylittlepage".