Setting implicit language in i18n Play 2.4 Scala template - scala

Question

Hello Stackoverflow community!
I have i18n working in my Play 2.4 application, so that's a good start.
What I want to do now is to override the implicit Lang sent to a template. For example, if the IP address is located in Sweden, I want to set the implicit Lang to Swedish regardless of what preferred language is set in the browser. How to do this?
This is my code:
My Application.scala controller:
package controllers
import javax.inject.Inject
import play.api.i18n.{I18nSupport, Lang, MessagesApi}
import play.api.mvc._
class Application #Inject() (val messagesApi: MessagesApi) extends Controller with I18nSupport {
def index = Action { implicit request =>
if (isIpAddressLocatedInSweden) {
implicit val langFromIp = Lang.apply("sv")
Logger.info("Language set to Swedish")
}
Ok(views.html.index())
}
private def isIpAddressLocatedInSweden: Boolean = {
[...]
}
}
My index.scala.html view:
#()(implicit messages: Messages, lang: Lang)
#main("Page Title") {
<span>#lang.toString()</span>
<h1>#Messages("home.title")</h1>
}
Unfortunately, the result is:
The <span> element contains the preferred browser language: "Lang(en,)"
The <h1> element contains the value I've written in messages.en
Thanks for any help!

Answer 1

I've done a little bit different:
I forced the result to the language in the query string.
It's a good form to keep the work and look for better approach later:
NOTE: I USED THE "MessagesApi" to make it happen.
package controllers
import play.api._
import play.api.mvc._
import play.api.i18n.I18nSupport
import play.api.i18n.Messages.Implicits._
import play.api.i18n.MessagesApi
import javax.inject.Inject
import play.api.i18n.Lang
import play.api.i18n._
class Application# Inject()(val messagesApi: MessagesApi) extends Controller with I18nSupport {
def index = Action {
implicit request =>
request.getQueryString("lang") match {
case Some(lang) => messagesApi.setLang(Ok(views.html.index()(messagesApi, Lang(lang))), Lang(lang))
case None => messagesApi.setLang(Ok(views.html.index()(messagesApi, Lang("en"))), Lang("en"))
}
}
}
conf/application.conf:
play.i18n.langs=["en","pt","fr"]
#()(implicit message: MessagesApi ,l: Lang)
<header>
<li>
<!-- change the language -->
<a href="./?lang=en">
<img src="#routes.Assets.versioned(" images/BR.png ")" />
</a>
</li>
<li>
<a href="./?lang=en">
<img src="#routes.Assets.versioned(" images/US.gif ")" />
</a>
</li>
<h1>#message("intro")</h1>
</header>
<p>#Html(message("description"))</p>
<p>#Html(message("description.education"))</p>

Answer 2

Conflicting implicits prevent exactly overriding Messages on Play 2.4 but I believe you can get what you were roughly looking for with the code below.
This is my code:
My conf/Application.conf:
# The application languages
# ~~~~~
play.i18n.langs = [ "en", "sv" ]
My conf/messages.sv
home.title=Svedish
My Application.scala controller:
package controllers
import javax.inject.Inject
import play.api.i18n.{I18nSupport, Lang, MessagesApi}
import play.api.mvc._
class IPMessages(lang: Lang, messages: MessagesApi) extends play.api.i18n.Messages(lang, messages){}
class Application #Inject() (val messagesApi: MessagesApi) extends Controller with I18nSupport {
def index = Action { implicit request =>
val langFromIp = if (isIpAddressLocatedInSweden) {
new Lang("sv")
} else {
request.acceptLanguages.head
}
implicit val ipMessages: IPMessages = new IPMessages(langFromIp, messagesApi)
Ok(views.html.index())
}
private def isIpAddressLocatedInSweden: Boolean = true
}
My index.scala.html view:
#()(implicit messages: IPMessages)
#main("Page Title") {
<span>#messages.toString()</span>
<h1>#messages("home.title")</h1>
}

Answer 3

This is the cleanest way I got it to work:
Code of my Application.scala controller:
class Application #Inject()(val messagesApi: MessagesApi) extends Controller with I18nSupport {
def index = Action { implicit request =>
val lang = if (isIpAddressLocatedInSweden) {
Lang.apply("sv")
} else {
Lang.preferred(request.acceptLanguages)
}
Ok(views.html.index()).withLang(lang)
}
private def isIpAddressLocatedInSweden: Boolean = {
[...]
}
}
The code of the index.scala.html view is unchanged.