#20 Add API to check existence of dblist item according to simple cri…

…terion

app/org/elastic4play/controllers/DBListCtrl.scala

@@ -4,7 +4,7 @@ import javax.inject.{ Inject, Singleton }
 
 import org.elastic4play.{ MissingAttributeError, Timed }
 import org.elastic4play.services.{ DBLists, Role }
-import play.api.libs.json.JsValue
+import play.api.libs.json.{ JsBoolean, JsValue }
 import play.api.mvc.{ Action, AnyContent, Controller }
 
 import scala.concurrent.{ ExecutionContext, Future }
@@ -60,4 +60,9 @@ class DBListCtrl @Inject() (
       }
       .getOrElse(Future.failed(MissingAttributeError("value")))
   }
+
+  @Timed("controllers.DBListCtrl.itemExists")
+  def itemExists(listName: String, itemKey: String, itemValue: JsValue): Action[AnyContent] = authenticated(Role.read).async { implicit request ⇒
+    dblists(listName).exists(itemKey, itemValue).map(r ⇒ Ok(JsBoolean(r)))
+  }
 }

app/org/elastic4play/services/DBList.scala

@@ -19,32 +19,43 @@ import scala.concurrent.duration.DurationInt
 import scala.concurrent.{ ExecutionContext, Future }
 
 @Singleton
-class DBListModel(dblistName: String) extends ModelDef[DBListModel, DBListItemEntity](dblistName) { model ⇒
+class DBListModel(dblistName: String) extends ModelDef[DBListModel, DBListItemEntity](dblistName) {
+  model ⇒
   @Inject def this(configuration: Configuration) = this(configuration.getString("dblist.name").get)
 
   val value: Attribute[String] = attribute("value", F.stringFmt, "Content of the dblist item")
   val dblist: Attribute[String] = attribute("dblist", F.stringFmt, "Name of the dblist")
+
   override def apply(attributes: JsObject) = new DBListItemEntity(this, attributes)
 
 }
 
 class DBListItemEntity(model: DBListModel, attributes: JsObject) extends EntityDef[DBListModel, DBListItemEntity](model, attributes) with DBListItem {
   def mapTo[T](implicit reads: Reads[T]): T = Json.parse((attributes \ "value").as[String]).as[T]
+
   def dblist: String = (attributes \ "dblist").as[String]
+
   override def toJson: JsObject = super.toJson - "value" + ("value" → mapTo[JsValue])
 }
 
 trait DBListItem {
   def id: String
+
   def dblist: String
+
   def mapTo[A](implicit reads: Reads[A]): A
 }
 
 trait DBList {
   def cachedItems: Seq[DBListItem]
+
   def getItems(): (Source[DBListItem, NotUsed], Future[Long])
+
   def getItems[A](implicit reads: Reads[A]): (Source[(String, A), NotUsed], Future[Long])
+
   def addItem[A](item: A)(implicit writes: Writes[A]): Future[DBListItem]
+
+  def exists(key: String, value: JsValue): Future[Boolean]
 }
 
 @Singleton
@@ -104,6 +115,15 @@ class DBLists @Inject() (
           dblistModel(newItem)
         }
     }
+
+    def exists(key: String, value: JsValue): Future[Boolean] = {
+      getItems()._1
+        .filter { item ⇒
+          (item.mapTo[JsValue] \ key).asOpt[JsValue].contains(value)
+        }
+        .runWith(Sink.headOption)
+        .map(_.isDefined)
+    }
   }
 
 }