Title and Page Identity

MediaWiki represents page titles in several complementary types, from the mutable, feature-rich Title class to lightweight immutable value objects and narrow identity interfaces. Understanding when to use each avoids unnecessary coupling to global state.

Type overview

Title

Mutable class implementing both LinkTarget and PageIdentity. Fetches data from the database and uses global state. Use in presentation code and legacy entry points; prefer lighter types in services.

TitleValue

Immutable value object implementing LinkTarget. No global state, no DB access. Holds namespace, DB key, fragment, and interwiki prefix. Preferred for data transfer between services.

PageReference

Minimal interface: getNamespace(), getDBkey(), getWikiId(). Used as the most general parameter type for services that only need to identify a page.

PageIdentity

Extends PageReference with getId(). Represents a page that may or may not exist. Title implements this interface.

TitleValue is the preferred type for internal data transfer. It is immutable, causes no side effects, and does not depend on global state. Prefer TitleValue (or PageReference / PageIdentity) over Title in service constructors and method signatures.

Title class

Title (namespace MediaWiki\Title) is the traditional representation of a page title. It implements LinkTarget, PageIdentity, and Stringable.

Creating Title objects

use MediaWiki\Title\Title;

// Parse user-supplied or wikitext title strings
$title = Title::newFromText( 'Talk:Foo bar' );
if ( $title === null ) {
    // Title string was invalid
}

// With an explicit default namespace
$title = Title::newFromText( 'Foo', NS_TEMPLATE ); // Template:Foo

Title::newFromText() maintains an in-process LRU cache of up to 1000 entries. It may return a previously constructed instance. If you need a guaranteed-fresh object, use makeTitle() or clone the returned instance.

Key Title methods

$title = Title::newFromText( 'Talk:Foo bar#Section' );

// Text form (spaces, no namespace prefix)
$title->getText();            // 'Foo bar'

// Full text including namespace and fragment
$title->getFullText();        // 'Talk:Foo bar#Section'

// Prefixed text (namespace + title, no fragment)
$title->getPrefixedText();    // 'Talk:Foo bar'

// Database key form (underscores)
$title->getDBkey();           // 'Foo_bar'
$title->getPrefixedDBkey();   // 'Talk:Foo_bar'

// Namespace integer
$title->getNamespace();       // NS_TALK (= 1)

// Fragment
$title->getFragment();        // 'Section'

// Article ID (0 if page does not exist; triggers DB lookup)
$title->getArticleID();       // e.g. 42

// Existence checks
$title->isKnown();            // true if the page exists or is a special page
$title->exists();             // true only if the page exists in the database
$title->isSpecialPage();      // true for NS_SPECIAL titles

// URL
$title->getLocalURL();        // '/wiki/Talk:Foo_bar'
$title->getFullURL();         // 'https://example.org/wiki/Talk:Foo_bar'

// Related titles
$title->getTalkPage();        // Title for the talk page
$title->getSubjectPage();     // Title for the subject page
$title->getBaseTitle();       // Title without the last subpage component

Title validation rules

Titles parsed by Title::newFromText() or TitleParser::parseTitle() must pass the following rules (see docs/Title.md):

Maximum 255 bytes in UTF-8 (512 bytes for NS_SPECIAL).
No illegal characters matching $wgLegalTitleChars negation.
No percent-encoded sequences (%XX).
No XML/HTML character references (&).
No leading/trailing whitespace after normalization.
Spaces and underscores are interchangeable.
First letter is uppercased when $wgCapitalLinks is enabled.

TitleValue

TitleValue (namespace MediaWiki\Title, since 1.23) is an immutable value object implementing LinkTarget. It stores namespace, DB key, fragment, and interwiki prefix.

use MediaWiki\Title\TitleValue;

// Direct construction (trusted data only — no validation beyond basic checks)
$tv = new TitleValue( NS_MAIN, 'Main_Page' );
$tv = new TitleValue( NS_USER, 'Alice', 'Contributions' ); // with fragment
$tv = new TitleValue( NS_MAIN, 'Foo', '', 'de' );           // interwiki

// Safe construction (returns null on invalid input)
$tv = TitleValue::tryNew( NS_MAIN, 'Main_Page' );

// From a PageReference
$tv = TitleValue::newFromPage( $pageReference );

// From another LinkTarget
$tv = TitleValue::newFromLinkTarget( $linkTarget );

// Accessors
$tv->getNamespace();   // int
$tv->getDBkey();       // string, underscored
$tv->getText();        // string, spaces (from LinkTargetTrait)
$tv->getFragment();    // string
$tv->getInterwiki();   // string

// Create a copy with a different fragment
$tv2 = $tv->createFragmentTarget( 'NewSection' );

Use TitleParser::makeTitleValueSafe() when constructing TitleValue from user input or untrusted sources. It applies full normalization and validation and returns null on failure.

TitleFormatter service

TitleFormatter (MediaWiki\Title\TitleFormatter, since 1.23, @since 1.28 in MediaWikiServices) converts title objects into display strings. Obtain it from the DI container:

$formatter = MediaWikiServices::getInstance()->getTitleFormatter();

Methods

use MediaWiki\Title\TitleValue;

$tv = new TitleValue( NS_USER, 'Alice' );

// Display text without namespace
$formatter->getText( $tv );            // 'Alice'

// Display text with namespace (spaces)
$formatter->getPrefixedText( $tv );    // 'User:Alice'

// DB key with namespace (underscores)
$formatter->getPrefixedDBkey( $tv );   // 'User:Alice' (underscored if spaces in title)

// Full text with namespace and fragment
$formatter->getFullText( $tv );        // 'User:Alice'

// Format from raw parts
$formatter->formatTitle(
    NS_USER_TALK,   // namespace
    'Alice',        // page text
    'Talk',         // fragment (optional)
    ''              // interwiki prefix (optional)
); // 'User talk:Alice#Talk'

// Namespace name (respects gender-sensitive languages)
$formatter->getNamespaceName( NS_USER, 'Alice' ); // 'User'

TitleFormatter::getText() and getPrefixedText() accept both LinkTarget and PageReference objects.

TitleParser service

TitleParser (MediaWiki\Title\TitleParser, since 1.23) parses text strings into TitleValue objects with full normalization and validation.

$parser = MediaWikiServices::getInstance()->getTitleParser();

Methods

use MediaWiki\Title\MalformedTitleException;

// Parse and throw on invalid input
try {
    $tv = $parser->parseTitle( 'Talk:Foo bar', NS_MAIN );
} catch ( MalformedTitleException $e ) {
    // Title string was invalid
    $errorKey = $e->getErrorMessage(); // e.g. 'title-invalid-characters'
}

// Parse safely — returns null on invalid input
$tv = $parser->makeTitleValueSafe( NS_USER, 'Alice', 'Contribs', '' );
if ( $tv !== null ) {
    // valid
}

parseTitle() applies:

HTML entity decoding and Unicode normalization.
Namespace and interwiki prefix detection.
Fragment extraction (#).
Whitespace/underscore normalization.
Length validation (255 / 512 byte limits).
Capital-letter normalization when $wgCapitalLinks is enabled.

LinkRenderer service

LinkRenderer (MediaWiki\Linker\LinkRenderer, since 1.28) generates HTML anchor elements for wiki pages. Obtain via MediaWikiServices:

$linkRenderer = MediaWikiServices::getInstance()->getLinkRenderer();

For links that require custom options (e.g. not rendering for comments), use LinkRendererFactory:

$linkRenderer = MediaWikiServices::getInstance()
    ->getLinkRendererFactory()
    ->create();

Methods

use MediaWiki\Title\TitleValue;
use Wikimedia\HtmlArmor\HtmlArmor;

$target = new TitleValue( NS_MAIN, 'Main_Page' );

// Auto-detect existence (DB lookup if not cached)
$html = $linkRenderer->makeLink( $target );
// <a href="/wiki/Main_Page">Main Page</a>  (blue or red depending on existence)

// Force blue-link style (no DB lookup)
$html = $linkRenderer->makeKnownLink(
    $target,
    'Go to main page',             // custom text (string or HtmlArmor)
    [ 'class' => 'mw-redirect' ],  // extra <a> attributes
    [ 'action' => 'history' ]      // query string parameters
);

// Force red-link style
$html = $linkRenderer->makeBrokenLink(
    $target,
    null,    // null = use default title text
    [],
    []
);

// Blue link with pre-trusted HTML as the link text
$html = $linkRenderer->makeKnownLink(
    $target,
    new HtmlArmor( '<b>Main Page</b>' )
);

// External link (since 1.43)
$html = $linkRenderer->makeExternalLink(
    'https://example.org',
    'Example',
    $currentTitle
);

makeLink() performs a database lookup to determine page existence if the title is not in LinkCache. Use makeKnownLink() when you know the page exists, or makePreloadedLink() when you want a blue-link style without any DB overhead.

Page identity interfaces

MediaWiki defines a hierarchy of interfaces for identifying pages:

PageReference
└── PageIdentity
    └── ExistingPageIdentity  (page_id > 0 is guaranteed)
    └── ProperPageIdentity    (not NS_SPECIAL and not interwiki)

Interface	Key methods	When to use
`PageReference`	`getNamespace()`, `getDBkey()`, `getWikiId()`	Parameter types in services that only need to identify a page
`PageIdentity`	+ `getId()`, `canExist()`, `exists()`	When you also need the page ID or existence flag
`ExistingPageIdentity`	(marker — `getId()` returns a positive integer)	When the page is guaranteed to exist
`ProperPageIdentity`	(marker — excludes special pages and interwiki)	Content pages that can be stored in the database

// Accept the widest compatible type
function renderBreadcrumb( PageReference $page ): string {
    return MediaWikiServices::getInstance()
        ->getTitleFormatter()
        ->getPrefixedText( $page );
}

// Require existence information
function getPageCategories( PageIdentity $page ): array {
    $id = $page->getId();
    // ...
}

Namespace constants

MediaWiki defines integer constants for the built-in namespaces in includes/Defines.php:

Constant	Value	Description
`NS_MAIN`	`0`	Main (article) namespace
`NS_TALK`	`1`	Talk namespace
`NS_USER`	`2`	User namespace
`NS_USER_TALK`	`3`	User talk namespace
`NS_PROJECT`	`4`	Project namespace (e.g. Wikipedia:)
`NS_PROJECT_TALK`	`5`	Project talk namespace
`NS_FILE`	`6`	File namespace
`NS_FILE_TALK`	`7`	File talk namespace
`NS_MEDIAWIKI`	`8`	MediaWiki (interface messages)
`NS_MEDIAWIKI_TALK`	`9`	MediaWiki talk namespace
`NS_TEMPLATE`	`10`	Template namespace
`NS_TEMPLATE_TALK`	`11`	Template talk namespace
`NS_HELP`	`12`	Help namespace
`NS_HELP_TALK`	`13`	Help talk namespace
`NS_CATEGORY`	`14`	Category namespace
`NS_CATEGORY_TALK`	`15`	Category talk namespace
`NS_SPECIAL`	`-1`	Special pages (not stored in DB)
`NS_MEDIA`	`-2`	Media namespace (for file links)

For namespace-related utility methods, use NamespaceInfo:

$nsInfo = MediaWikiServices::getInstance()->getNamespaceInfo();

$nsInfo->isTalk( NS_TALK );              // true
$nsInfo->getSubject( NS_USER_TALK );     // NS_USER
$nsInfo->getTalk( NS_USER );             // NS_USER_TALK
$nsInfo->isContent( NS_MAIN );           // true
$nsInfo->isCapitalized( NS_MAIN );       // true (when $wgCapitalLinks is set)
$nsInfo->hasSubpages( NS_USER );         // true
$nsInfo->getCanonicalName( NS_FILE );    // 'File'

REST API

Action API

PHP Services

Title and Page Identity

Type overview

Title

TitleValue

PageReference

PageIdentity

Title class

Creating Title objects

Key Title methods

Title validation rules

TitleValue

TitleFormatter service

Methods

TitleParser service

Methods

LinkRenderer service

Methods

Page identity interfaces

Namespace constants

Build docs developers (and LLMs) love

REST API

Action API

PHP Services

​Type overview

Title

TitleValue

PageReference

PageIdentity

​Title class

​Creating Title objects

​Key Title methods

​Title validation rules

​TitleValue

​TitleFormatter service

​Methods

​TitleParser service

​Methods

​LinkRenderer service

​Methods

​Page identity interfaces

​Namespace constants

Build docs developers (and LLMs) love

Type overview

Title class

Creating Title objects

Key Title methods

Title validation rules

TitleValue

TitleFormatter service

Methods

TitleParser service

Methods

LinkRenderer service

Methods

Page identity interfaces

Namespace constants