Sometimes we would like to call other HTTP services from within a Play application. Play supports this via its play.api.libs.ws.WS library, which provides a way to make asynchronous HTTP calls.

Any calls made by play.api.libs.ws.WS should return a scala.concurrent.Future[play.api.libs.ws.Response] which we can later handle with Play’s asynchronous mechanisms.

To send an HTTP request you start with WS.url() to specify the URL. Then you get a builder that you can use to specify various HTTP options, such as setting headers. You end by calling a final method corresponding to the HTTP method you want to use. For example:

val homePage: Future[play.api.libs.ws.Response] = WS.url("http://mysite.com").get()

Or:

val result: Future[ws.Response] = {
  WS.url("http://localhost:9001/post").post("content")
}

The call is asynchronous and you need to manipulate it as a Promise[ws.Response] to get the actual content. You can compose several promises and end with a Promise[Result] that can be handled directly by the Play server:

def feedTitle(feedUrl: String) = Action {
  Async {
    WS.url(feedUrl).get().map { response =>
      Ok("Feed title: " + (response.json \ "title").as[String])
    }
  }  
}

To post url-form-encoded data a Map[String, Seq[String]] needs to be passed into post()

WS.url(url).post(Map("key" -> Seq("value")))

Use the following properties to configure the WS client

• ws.timeout sets both the connection and request timeout in milliseconds
• ws.followRedirects configures the client to follow 301 and 302 redirects
• ws.useProxyPropertiesto use the system http proxy settings(http.proxyHost, http.proxyPort)
• ws.useragent to configure the User-Agent header field
• ws.acceptAnyCertificate set it to fail to use the default SSLContext

You can also get access to the underlying client using def client method

Next: OpenID Support in Play