Are imports and conditionals in Play's routes file possible? - scala

Question

I know that the earlier versions of Play used to support routes and conditionals (if blocks) in the routes file but I cannot find any such documentation for Play 2.2.x and HTTP routing says nothing about such a feature.
I want to replace this:
GET /api/users/:id com.corporate.project.controllers.UserController.get(id)
with a shorter version using import as follows:
import com.corporate.project.controllers._
GET /api/users/:id UserController.get(id)
Also, is it possible to have conditionals in the routes file? e.g.
if Play.isDev(Play.current())
GET /displayConfig DebugController.displayServerConfigs()

Answer 1

Package imports used to be possible with an SBT setting: routesImport += "com.corporate.project.controllers._". Not sure if it is still the case.
Also, is it possible to have conditionals in the routes file?
It might not be an ideal solution but we use routes tags to deal with this kind of conditional routes. You need a filter that checks if the route is annotated and runs your conditional logic.
Routes:
# #devmode
GET /displayConfig DebugController.displayServerConfigs()
Filter:
object DevmodeRouteFilter extends Filter {
private val DevmodeAnnotation = "#devmode"
override def apply(next: RequestHeader => Future[SimpleResult])(request: RequestHeader): Future[SimpleResult] = {
if(isDevRoute(request) && !Play.isDev(Play.current()) {
Play.current.global.onHandlerNotFound(request)
} else {
next(request)
}
}
private def isDevRoute(request: RequestHeader): Boolean = {
val comments = request.tags.getOrElse(Routes.ROUTE_COMMENTS, "")
comments.lines.exists { comment =>
comment.trim == DevmodeAnnotation
}
}
}
Don't forget to add the filter to the filter chain.

Answer 2

Thank you for your question, it is an interesting idea, so I went to the sources of Play2 and found that in my checkout of Play 2.2.3 in the play.core.Router.scala: object HandlerInvoker constructs controller as
handlerDef.ref.getClass.getClassLoader.loadClass(handlerDef.controller)
So I am afraid that support for partial class names (stored in handlerDef.controller) is not implemented in 2.2.x.
In 2.3.x there is commit https://github.com/playframework/playframework/commit/ba98dabd7ba374ed98f14f721835b898d27dd55b
that brought notion of package/namespace for the routes.
Please see changes in Routes.scala and RoutesCompiler.scala from that commit.
But I can't find description of that functionality in the documentation and I do not have Play 2.3.x to play with it now.
P.S.: Sample magic for advanced routing for 2.3.x described in http://java.dzone.com/articles/advanced-routing-play .