Play Framework Dependency Injection error - scala

Question

This is my code:
package controllers
import javax.inject.Inject
import scala.concurrent.Future
import play.api.Logger
import play.api.mvc.{ Action, Controller }
import play.api.libs.concurrent.Execution.Implicits.defaultContext
import play.api.libs.functional.syntax._
import play.api.libs.json._
// Reactive Mongo imports
import reactivemongo.api.Cursor
import reactivemongo.api.ReadPreference
import play.modules.reactivemongo.{ // ReactiveMongo Play2 plugin
MongoController,
ReactiveMongoApi,
ReactiveMongoComponents
}
// BSON-JSON conversions/collection
import reactivemongo.play.json._
import play.modules.reactivemongo.json.collection._
/*
* Example using ReactiveMongo + Play JSON library.
*
* There are two approaches demonstrated in this controller:
* - using JsObjects directly
* - using case classes that can be turned into JSON using Reads and Writes.
*
* This controller uses JsObjects directly.
*
* Instead of using the default Collection implementation (which interacts with
* BSON structures + BSONReader/BSONWriter), we use a specialized
* implementation that works with JsObject + Reads/Writes.
*
* Of course, you can still use the default Collection implementation
* (BSONCollection.) See ReactiveMongo examples to learn how to use it.
*/
class Application #Inject() (val reactiveMongoApi: ReactiveMongoApi)
extends Controller with MongoController with ReactiveMongoComponents {
def collection: Future[JSONCollection] =
database.map(_.collection[JSONCollection]("Persons"))
def index = Action { Ok("works") }
def create(name: String, age: Int) = Action.async {
val json = Json.obj(
"name" -> name,
"age" -> age,
"created" -> new java.util.Date().getTime())
collection.flatMap(_.insert(json)).map(lastError =>
Ok("Mongo LastError: %s".format(lastError)))
}
}
I´ve an error that said can´t find database value (database is a member of ReactiveMongoApi Trait) so I guess there is something wrong with dependency injection. I added also this line to the build sbt:
adding routesGenerator := InjectedRoutesGenerator
Any ideas? thank you!

Answer 1

You need to refer to the injected API. That is, replace database with reactiveMongoApi.database:
class Application #Inject() (val reactiveMongoApi: ReactiveMongoApi)
extends Controller with MongoController with ReactiveMongoComponents {
def collection: Future[JSONCollection] =
reactiveMongoApi.database.map(_.collection[JSONCollection]("Persons"))
...
}