Play2 based content negotiation

CNPlay.scala

import play.api.mvc._
import play.api.mvc.Results._
import play.api.http.MimeTypes._

def resource() = Action { implicit request =>
  negotiate(
    HTML ->
      (() => Ok("html")),
    JSON ->
      (() => Ok("json")),
    XML ->
      (() => Ok("xml"))
  )
}

def negotiate(handles: (String, () => Result)*)(implicit request: Request[_]): Result = {
  val handleMap = handles.toMap
  val handleValues = handles.map(_._1)
  val matchingType = request.acceptedTypes.
    foldLeft(None.asInstanceOf[Option[String]]) {
    (resultType, preferredType) =>
      if (resultType.isDefined) resultType
      else {
        handleValues.dropWhile(handle => !preferredType.accepts(handle)).headOption
      }
  }
  matchingType.map(mType => handleMap(mType).apply()).getOrElse(NotAcceptable)
}