Manual:Messages API

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MediaWiki messages can be used in code through the Message class and its associated methods. For instructions on the messages themselves, and tips on how to add new messages, see Localisation and in particular Localisation#General use (for developers).

Using messages in PHP[edit | edit source]

Here is a simple example:

$out = Xml::submitButton( wfMessage( 'submit' )->text() );

wfMessage() is a global function which acts as a wrapper for the Message class, creating a Message object. This example then invokes Message method text() which fetches the text of the 'submit' message in the current language, performs certain language transformations (such as gender and plural), and returns the unescaped message text.

Here is a more complex example using a message that takes a count and supports linguistic plural handling:

$out = Xml::label( wfMessage( 'numberofpages' )->numParams( $count )->text() );

The following sections explain the code.

Parameters[edit | edit source]

You pass parameters to messages that need them in several ways:

wfMessage( 'msg', 'param1', 'param2' )->plain();
wfMessage( 'msg' )->params( 'param1', 'param2' )->plain();
wfMessage( 'msg', array( 'param1', 'param2' ) )->plain();

The first approach is most common, use the second approach when mixing different types of parameters, and you can use the third to construct message objects dynamically from other data. There are different types of parameters:

wfMessage( 'msg' )->params( $username )->plain();
wfMessage( 'msg' )->rawParams( $link )-plain();
 
wfMessage( 'msg' )->numParams( $count )->plain();
wfMessage( 'msg' )->durationParams( $duration )->plain(); // since MW 1.22
wfMessage( 'msg' )->expiryParams( $expiry )->plain(); // since MW 1.22
wfMessage( 'msg' )->timeperiodParams( $period )->plain(); // since MW 1.22
wfMessage( 'msg' )->sizeParams( $size )->plain(); // since MW 1.22
wfMessage( 'msg' )->bitrateParams( $bitrate )->plain(); // since MW 1.22

The first one is a normal message substitution parameter. The second one substitutes the rawParams after the message has been otherwise processed; this means that these parameters are not available to parser functions nor are they escaped if escaping output format is used (see below). Make sure you escape them properly yourself.

Each function from the second group formats the value in a specific way before the substitution. numParams must be used if the message uses {{PLURAL:}}. In some cases you might not want to use it even though you have a number, for example a revision id. The other functions correspond to Language functions formatDuration, formatExpiry, formatTimePeriod, formatSize and formatBitrate, and are just shorthands for calling them directly.

Language[edit | edit source]

To override the language in which you want the message, there is one method and one shortcut for the common case of using wiki content language. In the latter case you can use either language code or language object. The usual language fallback chains apply, so the actual message you get may be in a different language than requested, if translation does not exist.

wfMessage( 'message-key' )->inContentLanguage();
wfMessage( 'message-key' )->inLanguage( $lang );

Output modes and escaping[edit | edit source]

The Message class, and thus the object returned by wfMessage, has five output modes:

  • plain(): returns the message text as-is; only parameters are substituted[1]
  • text(): transforms the message text (MessageCache::transform() which transforms all '{{}}', e.g., plurals)
  • escaped(): same as 'text', but also escapes it for use in HTML
  • parse(): parses the message text from wikitext to HTML (MessageCache::parse() which calls the Parser)
  • parseAsBlock(): the output is wrapped in block level html element, if not already, similarly to OutputPage::addWikiMsg

Remember that most Xml:: and Html:: functions escape everything fed into them, so use text() format with those to avoid double escaping. Hence the most common output format is text(). Also, make sure to use parse() or parseAsBlock() if the message has wikitext in it, otherwise the wikitext will just be escaped and output as plain text.

When using wfMessage() or $this->msg(), you should always specify an output type. text() is appropriate when you're outputting it through addWikiText().

Method chaining[edit | edit source]

Most Message methods return the current object, so you can conveniently call one after another to operate on an object before finally returning its text. This is called method chaining. Here is an example:

wfMessage( 'key' )
	->params( 'apple' )
	->numParams( $numOfApples )
	->setContext( $context )
	->inContentLanguage()
	->parse()

Additional methods of printing messages[edit | edit source]

The general message function in MediaWiki is wfMessage. However, since in a message the value of magic words can depend on the context, there are various wrappers to this function, that automatically set the correct context.

OutputPage has a few methods that append directly to the generated output. The useful ones are:

$out->addWikiMsg( 'pageheader' );
$out->wrapWikiMsg( '<div class="error">\n$1\n</div>', array( 'someerrormessage', $user->getName() ) );

Both of the above parse the wikitext in the context of current page before appending it to output buffer.

Classes extending ContextSource have a method msg that automatically sets the current context (language, current page etc.). It is therefore recommended to use $this->msg() for those classes, like special pages. Here is a non-exhaustive list of such classes:

  • CategoryViewer
  • HTMLForm
  • LogEventsList
  • DifferenceEngine
  • OutputPage
  • IndexPager
  • ImageHistoryList
  • ApiBase
  • ChangesList
  • Skin

Examples of correct usage:

wfMessage( 'key' )->numParams( 567 )->text();
$this->msg( 'key' )->numParams( 567 )->parse();

Examples of incorrect usage:

wfMessage( 'key', 345 )->parseInline(); # Number is not formatted correctly
$this->msg( 'key', 345 )->numParams( 234 )->plain() # Plural syntax is not converted in plain format

Using messages in JavaScript[edit | edit source]

See also ResourceLoader/Default modules#mediaWiki.message

To use the messages, we need to use ResourceLoader to make sure that the messages are available at client side first. For this, in your ResourceLoader modules, define the messages to be exported to client side. It is important to note that loading the mediawiki.jqueryMsg module significantly changes the behavior of mw.message and mw.msg. Generally, you should always load jqueryMsg.

Abbreviated real example:

$resourcePaths = array(
        'localBasePath' => __DIR__,
        'remoteExtPath' => 'Translate'
);
$wgResourceModules['ext.translate.groupselector'] = array(
        'styles' => 'resources/css/ext.translate.groupselector.css',
        'scripts' => 'resources/js/ext.translate.groupselector.js',
        'position' => 'top',
        'dependencies' => array(
                'mediawiki.jqueryMsg',
        ),
        'messages' => array(
                'translate-msggroupselector-projects',
                'translate-msggroupselector-search-placeholder',
                'translate-msggroupselector-search-all',
                'translate-msggroupselector-search-recent',
                'translate-msggroupselector-load-from-all',
                'translate-msggroupselector-view-subprojects',
        ),
) + $resourcePaths;

The messages defined in the above example will be available at client side and can be accessed by mw.messages( 'message-key-name' ). Some examples

$( '<a>' ).prop( 'href', '#' ).text( mw.message( 'translate-msggroupselector-projects' ).text() );

We can also pass the dynamic parameters to the message (i.e. the values for $1, $2, etc.) as shown below.

$( '<div>' ).text( mw.message( 'translate-msggroupselector-view-subprojects', count ).text() );

Note how we are using [jQuery].text to automatically escape our output properly. If this is not possible, here are few other examples:

  • If using jQuery's .append, escape manually .append( '<li>' + mw.message( 'example' ).escaped() + '</li>' );
  • If manually building an html string, always escape the message by creating a message object and calling .escaped() (don't use mw.message().text() or the mw.msg shortcut):
    '<foo>' + mw.message( 'example' ).escaped() + '</foo>';

There are some more or less used aliases like gM (legacy shortcut for mw.jqueryMsg.getMessageFunction()) but its use is deprecated in favour of mw.message( ... ).parse().

In the above examples, note that the message should be defined in an i18n file. If the message key is not found in any i18n file, the result will be the message key in angle brackets – like <message-key-foo>.

To use a message that is natively HTML and has no other logic or variables, such as MediaWiki:stub-threshold, use:

mw.message( 'stub-threshold' ).plain()

Raw html messages are highly discouraged.

Format options[edit | edit source]

If you don't specify the output format, mw.message just returns a Message object. To output the message itself, you should specify an output format. The formats are mostly the same as in PHP side:

  • mw.message( 'foobar' ).plain() returns the message text as-is; only parameters are substituted.
  • mw.message( 'foobar' ).text() Transforms the message text (all supported {{}} blocks are replaced with transformed results). See #Feature support in JavaScript for details of what is supported. For example, certain keywords ({{int:}}, {{GENDER}}, {{SITENAME}} etc.) work, but tranclusion (e.g. {{MediaWiki:}}) and server-side Magic words such as {{NUMBEROFEDITS}} or {{ns:Project}} do not work,
  • mw.message( 'foobar' ).escaped() HTML escaped version of text.
  • mw.message( 'foobar' ).parse() Parses the message text from wikitext to HTML. This supports everything from text mode, as well as most links, and whitelisted HTML.

Warning: If the mediawiki.jqueryMsg module is not loaded, all of the above methods behave essentially like plain() with possible escaping.

Note: There is no equivalent of parseAsBlock. Where necessary, wrap the output to an element yourself.

Feature support in JavaScript[edit | edit source]

  • MediaWiki 1.19 onwards, the messages for JavaScript can contain PLURAL and GENDER directives.
  • MediaWiki 1.20 onwards, the messages for JavaScript can contain GRAMMAR directive.
  • MediaWiki 1.21 (1.21wmf8) onwards, the messages for JavaScript can contain uses of the INT directive.
  • MediaWiki 1.21 (1.21wmf9) onwards, some FORMATNUM support is available, primarily localization for digits and decimal separators.
  • MediaWiki 1.21 (1.21wmf10) onwards, messages can also have both wikilinks and external links. However, features like the pipe trick are not supported.
  • MediaWiki 1.22 (1.22wmf2) onwards, parsed messages can have limited HTML. Currently <b> and <i> are supported.

The keywords are case insensitive, but uppercase is preferred.

Notes about gender, grammar, plural[edit | edit source]

See also Localisation#Switches in messages…

In general, GENDER, GRAMMAR and PLURAL magic words work identically in both PHP and JavaScript sides.

  1. You must use text, escaped, parse or parseAsBlock output formats for them to work.
  2. You need to pass the relevant parameter as normal parameter to the message.
    • The parameter is the number for PLURAL; the username for GENDER in PHP; the gender from preferences or an user object for GENDER in JavaScript (see below).
    • For plural in PHP, you need to use numParams for the number, see also #Chaining.

PLURAL syntax example[edit | edit source]

# Simple plural
'key' => '$1 crying {{PLURAL:$1|baby|babies}}'

GENDER in JavaScript[edit | edit source]

Note: You must have the mediawiki.jqueryMsg module explicitely loaded for this to work!

If you have a message, say, 'message-key-gender-foo' => '{{GENDER:$1|he|she}} created an article' , in JavaScript, you can use it as given below:

mw.message( 'message-key-gender-foo', 'male' ).text(); // returns 'he created an article'
mw.message( 'message-key-gender-foo', 'female' ).text(); // returns 'she created an article'

Instead of passing the gender directly, we can pass a User object - i.e. mw.User object with a gender attribute to mw.msg. For e.g., the current user object.

var user = mw.user; // current user
mw.message( 'message-key-gender-foo', user ).text(); // The message returned will be based on the gender of the current user.

If the gender passed to mw.msg is invalid or unknown, gender neutral form will be used as defined for each language.

PLURAL in JavaScript[edit | edit source]

Note: You must have the mediawiki.jqueryMsg module explicitely loaded for this to work!

If you have a message, say 'message-key-plural-foo' => 'There {{PLURAL:$1|is|are}} $1 {{PLURAL:$1|item|items}}' , in JavaScript, you can use it as given below:

mw.message( 'message-key-plural-foo', count ).text();
// returns 'There is 1 item' if count = 1
// returns 'There are 6 items' if count = 6

Deprecated wfMsg* functions[edit | edit source]

Code change Description
Instead of:
wfMsg( 'key' );

Do:

wfMessage( 'key' )->text();
 
Instead of:
wfMsgExt( 'key', array( 'parse' ), 'apple' );

Do:

wfMessage( 'key', 'apple' )->parseAsBlock();
Use full parsing, and wrap the output in block-level HTML tags.
Instead of:
wfMsgExt( 'key', array( 'parseinline' ), 'apple' );

Do:

wfMessage( 'key', 'apple' )->parse();
Use full parsing. Parseinline is used because it is more useful when pre-building HTML. In normal use it is better to use OutputPage::(add|wrap)WikiMsg.
Instead of:
wfMsgExt( 'key', array( 'parsemag' ), 'apple', 'pear' );

Do:

wfMessage( 'key', 'apple', 'pear' )->text();
Places where HTML cannot be used. {{-transformation is done.
Instead of
wfMsgHtml( 'key', 'apple' );

Do:

wfMessage( 'key' )->rawParams( 'apple' )->escaped();
wfMsgHtml does not escape parameters, so you need to use rawParams. Please double check that the parameter really is safe for html output.
Instead of:
wfMsgForContent( 'key' );

Do:

wfMessage( 'key' )->inContentLanguage()->text();
Get a message in the wiki's content language ($wgLanguageCode).
Instead of:
wfMsgForContentNoTrans( 'key' );

Do:

wfMessage( 'key' )->inContentLanguage()->plain();
Get a message in the wiki's content language ($wgLanguageCode) but don't transform the message.
Instead of:
wfEmptyMsg( 'key', $message = wfMsgForContent( 'key' ) );

Do:

wfMessage( 'key' )->inContentLanguage()->isBlank();
Checks if the 'key' message in the wiki's content language is empty.

See also[edit | edit source]

Notes[edit | edit source]

  1. While using this mode to display HTML content is possible, the translation team recommends using wikitext instead and using parse() mode to transform it into HTML.