How can I serialize Sangria responses with json4s and Akka HTTP? - scala

Question

I'm working through a slight variation of Sangria's Getting Started, using Akka HTTP. I'm attempting to use json4s-jackson as the serializaltion lib, but am running in to some trouble getting the response I want.
Specifically, the serialized response I get is the JSON version of the (StatusCode, Node) tuple:
{
"_1": {
"allowsEntity": true,
"defaultMessage": "OK",
"intValue": 200,
"reason": "OK"
},
"_2": {
"data": {
"foo": {
"id": "1",
"name": "Foo"
}
}
}
}
The data portion is correct, but obviously I just want that and not the first element of the serialized tuple.
I'm using akka-http-json4s, so my trait with route looks like:
case class GraphQlData(query: String, operation: Option[String])
trait FooController {
import de.heikoseeberger.akkahttpjson4s.Json4sSupport._
implicit val serialization = jackson.Serialization
implicit val formats = DefaultFormats
val fooRoutes = post {
entity(as[GraphQlData]) { data =>
QueryParser.parse(data.query) match {
// query parsed successfully, time to execute it!
case Success(queryAst) =>
complete {
Executor
.execute(
SchemaDefinition.FooSchema,
queryAst,
new FooService,
operationName = data.operation
)
.map(OK -> _)
.recover {
case error: QueryAnalysisError => BadRequest -> error.resolveError
case error: ErrorWithResolver => InternalServerError -> error.resolveError
}
}
// can't parse GraphQL query, return error
case Failure(error) =>
complete(BadRequest -> error.getMessage)
}
}
}
implicit def executionContext: ExecutionContext
}
For the life of me I can't figure out what's wrong. I've been looking at sangria-akka-http-example but it seems to be exactly the same, with the exception of using spray-json instead of json4s.
Ideas? Thanks!

Answer 1

Ah, figured it out. I neglected to add
import sangria.marshalling.json4s.jackson._
to the trait defining the route. Adding it does the trick.

Answer 2

Just wanted to provide a quick update to this answer for the full GraphQLRequest. Now the variables are included in the request.
import de.heikoseeberger.akkahttpjson4s.Json4sSupport
import org.json4s._
import org.json4s.JsonAST.JObject
import sangria.marshalling.json4s.jackson._
case class GQLRequest(query: String, operationName: Option[String], variables: JObject)
trait SomeJsonSupport extends Json4sSupport {
implicit val serialization = jackson.Serialization
implicit val formats = DefaultFormats
}
trait GraphQLResource extends SomeJsonSupport{
implicit val timeout:Timeout
implicit val system:ActorSystem
import system.dispatcher
def graphqlRoute: Route =
(post & path("graphql")) {
entity(as[GQLRequest]) { requestJson =>
println(s"This is the requestJson = $requestJson")
graphQLEndpoint(requestJson)
}
} ~
get {
println(s"This is working")
getFromResource("graphiql.html")
}
def graphQLEndpoint(requestJson: GQLRequest): Route = {
val route = QueryParser.parse(requestJson.query) match {
case Success(query) =>
println(s"This is the query $query")
val vars = requestJson.variables match {
case jObj:JObject => jObj
case _ => JObject(List.empty)
}
val futureJValue = Executor.execute(clientSchema,
query,
NclhGqlRequest(this),
operationName = requestJson.operationName,
variables = vars)
val futureTupleStatusCodeJValue = futureJValue.map(OK -> _).recover {
case error: QueryAnalysisError => BadRequest -> error.resolveError
case error: ErrorWithResolver => InternalServerError -> error.resolveError
}
complete(futureTupleStatusCodeJValue)
case Failure(error) =>
complete(BadRequest, error.getMessage)
}
route
}