Routes with optional parameter - Play 2.1 Scala

Question

So in Play 2.0 I had this:

GET     /tasks/add              controllers.Tasks.addTask(parentId: Option[Long] = None)
GET     /tasks/:parentId/add    controlle         


        

Answer 1

Play 2.0 supported Option in path parameters, Play 2.1 no longer supports this, they removed the PathBindable for Option.

One possible solution would be:

package extensions
import play.api.mvc._
object Binders {
  implicit def OptionBindable[T : PathBindable] = new PathBindable[Option[T]] {
    def bind(key: String, value: String): Either[String, Option[T]] =
      implicitly[PathBindable[T]].
        bind(key, value).
        fold(
          left => Left(left),
          right => Right(Some(right))
        )

    def unbind(key: String, value: Option[T]): String = value map (_.toString) getOrElse ""
  }
}

And add this to Build.scala using routesImport += "extensions.Binders._". Run play clean ~run and it should work. Reloading the Binders on the fly only sometimes works.

Answer 2

I had the same thing and more if you specify the pass as GET/foo:id and controllers.Application.foo(id : Option[Long] ?= None) you get an error It is not allowed to specify a fixed or default value for parameter: 'id' extracted from the path on the other side you can do as follows GET/foo controllers.Application.foo(id : Option[Long] ?= None) and it will work expecting that your request looks like as .../foo?id=1

Answer 3

I think you have to add a question mark:

controllers.Tasks.addTask(parentId: Option[Long] ?= None)

Answer 4

From this routes-with-optional-parameter the suggestion goes like:

GET   /                     controllers.Application.show(page = "home")
GET   /:page                controllers.Application.show(page)

Answer 5

The simple solution to your problem, without having to pass a default value, is to add a simple proxy method that wraps the parameter in an option.

Routes:

GET     /tasks/add              controllers.Tasks.addTask()
GET     /tasks/:parentId/add    controllers.Tasks.addTaskProxy(parentId: Long)

Controller:

def addTask(parentId: Option[Long] = None) = Action { 
    Ok(views.html.addTask(taskForm, parentId))  
}

def addTaskProxy(parentId: Long) = addTask(Some(parentId))