Set of examples of how to use ReactiveMongo with the Play-ReactiveMongo Plugin.

application.conf

# mongo settings
mongodb.uri="mongodb://reactive:<password>@paulo.mongohq.com:10065/reactive"

ComplaintController.scala

def watchCollection = WebSocket.using[JsValue] { request =>
  // Inserts the received messages into the capped collection
    val in = Iteratee.flatten(futureCollection.map(collection => Iteratee.foreach[JsValue] { json =>
      Logger.debug("received " + json)
      collection.insert(json)
    }))

    // Enumerates the capped collection
    val out = {
      val futureEnumerator = futureCollection.map { collection =>
      // so we are sure that the collection exists and is a capped one
        val cursor: Cursor[JsValue] = collection
          // we want all the documents
          .find(Json.obj())
          // the cursor must be tailable and await data
          .options(QueryOpts().tailable.awaitData)
          .cursor[JsValue]

        // ok, let's enumerate it
        cursor.enumerate
      }
      Enumerator.flatten(futureEnumerator)
    }

    // We're done!
    (in, out)
}

GridFSController.scala

def getProfilePic(email : String) = Action {
    Async {
       users.find(Json.obj("email" -> email)).one[JsValue].filter(_.isDefined).flatMap {
          maybeUser =>
            val profileId = (maybeUser.get \ "profilePic" \ "_id" \ "$oid").as[String]
            serve(gridFS, gridFS.find(BSONDocument("_id" -> new BSONObjectID(profileId))))
       }
    }

}

play.plugins

400:play.modules.reactivemongo.ReactiveMongoPlugin

UserController.scala

def update(email : String) = Action(parse.json) {
    request =>
      Async {
        users.update(findByEmail(email), request.body).map {
          lastError =>
            if (lastError.ok)
              Ok(Json.obj("results" -> "success"))
            else
              BadRequest(Json.obj("error" -> s"Error occurred: ${lastError.errMsg.getOrElse("No details.  Argh!")}"))

        }
      }
}