Manual:Using custom namespaces/en

In addition to the built-in namespaces, it is possible to add custom namespaces to a MediaWiki installation, to further separate content and allow more logical organization.

Custom namespaces are simple to manage using the  configuration directive. It is also possible to define alias names for custom (and also predefined) namespaces, using the  configuration directive.

Creating a custom namespace
You register additional namespaces by adding them to the global variable to your  file. All namespaces require a unique numerical index in this array. As an example of simple custom namespace creation, adding the following lines to  defines a "Foo" namespace 3000 and its associated "Foo talk" namespace:


 * Pick an unused number
 * As a convention, the namespaces numbered 100-199 are reserved for site-specific namespaces, although there are some extensions that don't follow this convention. Extension writers use higher numbers, up to 32767. When choosing your index, you should avoid any number already in extension default namespaces, since you might want to install that extension later. Thus numbers from 3000 and higher are a good pick for system administrators to define their custom namespaces.


 * Even then odd
 * Note the namespace array index is 3000 in the above example.
 * an even namespace index denotes a subject namespace.
 * the odd index immediately following that number denotes its associated discussion ("talk") namespace


 * Create the talk namespace too
 * You typically create a discussion "Talk" namespace along with each custom namespace. With this example, if you move a page into the "Foo" namespace, will be prompted to move its associated talk page, if any, and if you choose to do so, MediaWiki will place the talk page in "Foo talk".


 * No spaces
 * Use underscores instead of spaces when registering namespace names. "My Namespace" is invalid here; use "My_Namespace" instead.

The uppercase part does not permit hyphens but they can still be safely added to the prefix title. Example:
 * No hyphens


 * Name the numbers you pick
 * The example defines constants for the namespace IDs, so that you can refer to these namespaces later on in the configuration, for example in, , or.

You could go on to configure additional settings for your new namespace.


 * Do it early
 * Manipulation of  must be completed during MediaWiki initialization; for instance it cannot be manipulated in a post-initialization hook like.


 * Watch out for collisions with URL protocols
 * MediaWiki's linking code knows about a number of URL protocols, defined in the variable. If your namespace name is identical to one of these protocols, you're going to have trouble creating wikilinks to pages in your custom namespace. This most commonly arises when someone tries to create a "News" namespace, because   is a URL protocol for NNTP newsgroups.
 * To avoid this issue, you can deregister the relevant URL protocol by adding the following code to LocalSettings.php (replacing  by the lowercased name of the protocol you wish to remove):

In extensions
Extensions often add their own namespaces, such as the extension's "Topic" namespace. An extension can unconditionally add to  as described above, or if its namespace registration is conditional (for example  only defines its "Schema" namespace on the wiki where it stores schemas), then it can add a handler function for the  hook that decides what to do.

The timing of registering extensions is subtle. Functions that extensions register with are executed too late to register additional namespaces. So extensions should bind the hook at file scope (in MyExtension.php) and check there whether the wiki should activate the extra namespace or not. Extensions can configure namespace permissions and content handlers unconditionally at file scope since they do not require the namespace to actually be created.

The new extension.json registration system has a  key for an extension to list its namespaces that should always exist. From the extension:

It also supports the  hook.

Content namespaces
When building the site statistics page (see Special:Statistics), MediaWiki uses values stored in the database to calculate certain totals. One particular total is the "number of articles" or "number of content pages" figure.

For a page to be considered an article, or proper content, it must:


 * Be in the main namespace, or a defined content namespace
 * Not be a redirect page
 * Contain at least one internal link

When creating custom namespaces to hold additional content, it is a good idea to indicate this in the configuration. This is done via the configuration directive.

To extend the example above, one might add the following to :


 * or

MediaWiki will now consider pages in the "Foo" namespace to be articles, if they meet the remaining criteria, and will include them when updating the site statistics counters.

Running maintenance scripts

 * When adjusting the value of, it is a good idea to run either the   or   script to update the internal statistics cache (see ).

Why you would want a custom namespace
There are several reasons on why you would want this:


 * A custom namespace can be used to hold content that should not be shown on the search results page, for example pages that are used only for transclusion.
 * Certain namespace require additional privilege(s), i.e. for reading or editing
 * You want certain namespace not to be subjected to certain limitation or default settings ( for example)
 * A uniform prefix for specific content(s), which is searchable for that namespace only
 * If you're an MW developer, sometimes you need to have a custom namespace for your extension(s)

Dealing with existing pages
When storing page records, MediaWiki uses a namespace's numerical index, along with the remaining title text. Thus, when a page is created in a namespace that doesn't exist, e.g. "Bar:Some page", it is treated as being in the main namespace.

This can cause problems if adding a custom namespace definition for "Bar" at a later date, as MediaWiki will look for a page indexed via the proper namespace, but won't be able to find it, thus making the content inaccessible.

To correct this problem, there are three main approaches.

Move conflicting pages
If the number of pages affected is small (e.g. "Bar" held five pages created before the namespace was defined in the site configuration), then the following approach might be suitable:


 * 1) Comment out the namespace definition in the configuration file
 * 2) Access each affected page, and move it out of the pseudo-namespace, e.g. move "Bar:Some page" to "Bar2:Some page"
 * 3) Un-comment the namespace definition
 * 4) Move the affected pages back into the new namespace

Use a maintenance script
Within the maintenance directory, there is a maintenance script which performs the above operation more effectively for a large number of pages;  It is simple to use, but as with all MediaWiki maintenance scripts, consult the available usage information first (use  as an option).

Use a database query
To move all pages "Bar:Some page" into namespace 3000, make the following database query:

To handle discussion pages:

The above example is wrong. It should look for "Bar_Talk:" or "Bar_talk:" or how MediaWiki saves that inside the page_title field... After such fiddling, run the script and the  script to update internal links and search results in your wiki. Note that external search engines like Google will take some time to update their index.

Removing custom namespaces
The problem addressed above also occurs when a custom namespace definition is removed; MediaWiki is no longer aware of the numerical index for the namespace, and attempts to search the main namespace for the desired pages, leading to inaccessible content. This is a rare occurrence, since most sites will not need namespaces removed, but it is a problem. (See mailing list discussion).

Avoid namespace conflicts
In order for you to avoid namespace conflicts e.g. your namespace has the same number as a namespace defined by an extension, the extension namespace list shows you which numbers to avoid to prevent conflicts.

Defining $wgNamespacesToBeSearchedDefault, $wgNamespacesWithSubpages, $wgContentNamespaces or $wgNamespaceAliases for an ID not associated to any existing namespace in $wgExtraNamespaces doesn't break the wiki; MediaWiki gracefully ignores such configurations.

Styling namespaces
For example, to set the background color of pages in a particular namespace (and its associated talk namespace) you can add the following code to your common.css:

where  is the namespace's index and   is the color you want as its background color.