Coproduct Routers in the Playground

Playground.scala

package io.finch.playground

import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.scala.DefaultScalaModule
import com.twitter.finagle.{Service, Filter, Httpx}
import com.twitter.util.{Future, Await}

import io.finch.{Endpoint => _, _}
import io.finch.micro._
import io.finch.request._
import io.finch.route.{Endpoint => _, _}
import io.finch.jackson._

/**
 * GET /user/groups        -> Seq[Group]
 * POST /groups?name=foo   -> Group
 * PUT /user/groups/:group -> User
 */
object Main extends App {

  // enable finch-jackson magic
  implicit val objectMapper: ObjectMapper = new ObjectMapper().registerModule(DefaultScalaModule)

  // model
  case class Group(ownerId: Int = 0, name: String)
  case class User(id: Int, groups: Seq[Group])

  case class UnknownUser(id: Int) extends Exception(s"Unknown user with id=$id")
  case object WrongSecret extends Exception("You shell not pass!")

  val currentUser: RequestReader[User] =
    header("X-Secrect").embedFlatMap {
      case "open sesame" => User(0, Seq.empty[Group]).toFuture
      case _ => WrongSecret.toFutureException
    }

  // GET /user/groups -> Seq[Group]
  val getUserGroups: Router[RequestReader[Seq[Group]]] =
    Get / "user" / "groups" /> (currentUser ~> { userId => Seq(Group(userId, "foo"), Group(userId, "bar")) })

  // POST /groups?name=foo -> Group
  val postGroup: Router[RequestReader[Group]] =
    Post / "groups" /> (currentUser :: param("name")).as[Group]

  // PUT /user/groups/:group -> User
  val putUserGroup: Router[RequestReader[User]] =
    Put / "user" / "groups" / string /> { group => 
      currentUser ~> { User(_, Seq(group)) }  
    }

  // an API endpoint
  val api: Router[RequestReader[Seq[User]] :+: RequestReader[Group] :+: RequestReader[User] :+: CNil] =
    getUserGroups :+: postGroup :+: putUserGroup

  Await.ready(Httpx.serve(":8081", api))
}