JSON support for spray.io

[mirelon]

I use version 0.3.1, where the json support is already supported. There is a method asJson, which returns JValue. According to http://spray.io/documentation/1.2.2/spray-httpx/json4s-support/ there is an implicit Marshaller when using trait Json4sSupport. But when using spray as server, I need to provide ToResponseMarshaller.

I wonder now, whether I need to code my own, or it should be a part of json support in scala-activerecord. I am a bit inclined to the latter option.

What have I tried:

trait ActiveRecordToSprayJsonSupport extends Json4sSupport {
  override implicit def json4sFormats: Formats = org.json4s.DefaultFormats

  implicit def toToResponseMarashaller(implicit tMarshaller: Marshaller[ActiveRecord]): ToResponseMarshaller[ActiveRecord] = new ToResponseMarshaller[ActiveRecord] {
    override def apply(value: ActiveRecord, ctx: ToResponseMarshallingContext): Unit = {
      val mCtx = new MarshallingContext {
        override def tryAccept(contentTypes: Seq[ContentType]): Option[ContentType] = ctx.tryAccept(contentTypes)

        override def startChunkedMessage(entity: HttpEntity, ack: Option[Any], headers: Seq[HttpHeader])(implicit sender: ActorRef): ActorRef = ctx.startChunkedMessage(HttpResponse(entity = entity, headers = headers.toList), ack)

        override def rejectMarshalling(supported: Seq[ContentType]): Unit = ctx.rejectMarshalling(supported)

        override def marshalTo(entity: HttpEntity, headers: HttpHeader*): Unit = ctx.marshalTo(HttpResponse(entity = entity, headers = headers.toList))

        override def handleError(error: Throwable): Unit = ctx.handleError(error)
      }
      tMarshaller(value, mCtx)
    }
  }
}

The models:

case class Product(name: String) extends ActiveRecord {
  lazy val comments = hasMany[Comment]
}
object Product extends ActiveRecordCompanion[Product]

case class Comment(text: String) extends ActiveRecord {
}
object Comment extends ActiveRecordCompanion[Comment]

And the service:

trait ProductService extends HttpServiceActor with HttpService with ActiveRecordToSprayJsonSupport {
...
        Product.find(id) match {
          case Some(r: Product) => requestContext.complete(r)
          case _ => requestContext.complete(StatusCodes.NotFound)
        }
...
}

And here is what I have got:

org.json4s.package$MappingException: Can't find ScalaSig for class java.lang.Object
    at org.json4s.reflect.ScalaSigReader$.findClass(ScalaSigReader.scala:42)
    at org.json4s.reflect.ScalaSigReader$.org$json4s$reflect$ScalaSigReader$$read$1(ScalaSigReader.scala:36)
    at org.json4s.reflect.ScalaSigReader$.org$json4s$reflect$ScalaSigReader$$read$1(ScalaSigReader.scala:36)
    at org.json4s.reflect.ScalaSigReader$.readField(ScalaSigReader.scala:38)
    at org.json4s.reflect.Reflector$ClassDescriptorBuilder$$anonfun$3.apply(Reflector.scala:66)
    at org.json4s.reflect.Reflector$ClassDescriptorBuilder$$anonfun$3.apply(Reflector.scala:65)
    at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:245)
    at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:245)
    at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
    at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:48)
    at scala.collection.TraversableLike$class.map(TraversableLike.scala:245)
    at scala.collection.AbstractTraversable.map(Traversable.scala:104)
    at org.json4s.reflect.Reflector$ClassDescriptorBuilder.fields(Reflector.scala:65)
    at org.json4s.reflect.Reflector$ClassDescriptorBuilder.fields(Reflector.scala:78)
    at org.json4s.reflect.Reflector$ClassDescriptorBuilder.properties(Reflector.scala:82)
    at org.json4s.reflect.Reflector$ClassDescriptorBuilder.result(Reflector.scala:158)
    at org.json4s.reflect.Reflector$.createDescriptor(Reflector.scala:50)
    at org.json4s.reflect.Reflector$$anonfun$describe$1.apply(Reflector.scala:44)
    at org.json4s.reflect.Reflector$$anonfun$describe$1.apply(Reflector.scala:44)
    at org.json4s.reflect.package$Memo.apply(package.scala:39)
    at org.json4s.reflect.Reflector$.describe(Reflector.scala:44)
    at org.json4s.Extraction$.decomposeObject$1(Extraction.scala:90)
    at org.json4s.Extraction$.internalDecomposeWithBuilder(Extraction.scala:196)
    at org.json4s.Extraction$.decomposeWithBuilder(Extraction.scala:67)
    at org.json4s.native.Serialization$.write(Serialization.scala:43)
    at org.json4s.native.Serialization$.write(Serialization.scala:37)
    at spray.httpx.BaseJson4sSupport$$anonfun$json4sMarshaller$1.apply(BaseJson4sSupport.scala:26)
    at spray.httpx.BaseJson4sSupport$$anonfun$json4sMarshaller$1.apply(BaseJson4sSupport.scala:26)
    at spray.httpx.marshalling.Marshaller$MarshallerDelegation$$anonfun$apply$1.apply(Marshaller.scala:58)
    at spray.httpx.marshalling.Marshaller$MarshallerDelegation$$anonfun$apply$1.apply(Marshaller.scala:58)
    at spray.httpx.marshalling.Marshaller$MarshallerDelegation$$anonfun$apply$2.apply(Marshaller.scala:61)
    at spray.httpx.marshalling.Marshaller$MarshallerDelegation$$anonfun$apply$2.apply(Marshaller.scala:60)
    at spray.httpx.marshalling.Marshaller$$anon$2.apply(Marshaller.scala:47)

[binkabir]

You dont need to add the Json4sSupport to your spray route for you serialize return values of Active record.

I tried your code this way and it worked.

    trait ProductService extends  HttpService{
          .........................
              Product.find(id).headOption match {
                   case Some(r:State) => complete(r.toJson)
                  case None => complete(StatusCodes.NotFound)
       }