§Messages and internationalization

§Specifying languages supported by your application

A valid language code is specified by a valid ISO 639-2 language code, optionally followed by a valid ISO 3166-1 alpha-2 country code, such as fr or en-US.

To start you need to specify the languages supported by your application in the conf/application.conf file:

application.langs="en,en-US,fr"

§Externalizing messages

You can externalize messages in the conf/messages.xxx files.

The default conf/messages file matches all languages. Additionally you can specify language-specific message files such as conf/messages.fr or conf/messages.en-US.

You can then retrieve messages using the play.api.i18n.Messages object:

val title = Messages("home.title")

All internationalization API calls take an implicit play.api.i18.Lang argument retrieved from the current scope. You can also specify it explicitly:

val title = Messages("home.title")(Lang("fr"))

Note: If you have an implicit Request in the scope, it will provide an implicit Lang value corresponding to the preferred language extracted from the Accept-Language header and matching one of the application supported languages. You should add a Lang implicit parameter to your template like this: @()(implicit lang: Lang).

§Messages format

Messages are formatted using the java.text.MessageFormat library. For example, assuming you have message defined like:

files.summary=The disk {1} contains {0} file(s).

You can then specify parameters as:

Messages("files.summary", d.files.length, d.name)

§Notes on apostrophes

Since Messages uses java.text.MessageFormat, please be aware that single quotes are used as a meta-character for escaping parameter substitutions.

For example, if you have the following messages defined:

info.error=You aren''t logged in!

example.formatting=When using MessageFormat, '''{0}''' is replaced with the first parameter.

you should expect the following results:

Messages("info.error") == "You aren't logged in!"

Messages("example.formatting") == "When using MessageFormat, '{0}' is replaced with the first parameter."

§Retrieving supported language from an HTTP request

You can retrieve the languages supported by a specific HTTP request:

def index = Action { request =>
  Ok("Languages: " + request.acceptLanguages.map(_.code).mkString(", "))
}

Next: The application Global object