Basic Play optional authenticated action.

gistfile1.scala

import play.api.mvc._

case class Context(email: Option[String])

class AuthenticatedRequest[A](val context: Context, request: Request[A]) extends WrappedRequest[A](request)

object MaybeAuthenticated extends ActionBuilder[AuthenticatedRequest] {
  def invokeBlock[A](request: Request[A], block: (AuthenticatedRequest[A]) => Future[SimpleResult]) = {
    request.session.get("email").map { email =>
      block(new AuthenticatedRequest(Context(Some(email)), request))
    } getOrElse {
      block(new AuthenticatedRequest(Context(None), request))
    }
  }
}

def myAction = MaybeAuthenticated { implicit request =>
  request.context.email.map { email
    Ok("The current user is " + email)
  } getOrElse {
    Ok("No logged in user")
  }
}