How to perform a simple json post with spray-json in spray? - scala

Question

I'm trying to perform a simple json post with spray. But it seems that i can get an http entity for a json object that can be Marshall.
here is my error:
[error]
...../IdeaProjects/PoolpartyConnector/src/main/scala/org/iadb/poolpartyconnector/thesaurusoperation/ThesaurusCacheService.scala:172:
could not find implicit value for evidence parameter of type
spray.httpx.marshalling.Marshaller[spray.json.JsValue]
[error] val request =
Post(s"$thesaurusapiEndpoint/$coreProjectId/suggestFreeConcept?",
suggestionJsonBody)
and the code that comes with it:
override def createSuggestedFreeConcept(suggestedPrefLabel: String, lang: String, scheme: String, b: Boolean): String = {
import system.dispatcher
import spray.json._
val pipeline = addCredentials(BasicHttpCredentials("superadmin", "poolparty")) ~> sendReceive
val label = LanguageLiteral(suggestedPrefLabel, lang)
val suggestion = SuggestFreeConcept(List(label), b, Some(List(scheme)), None, None,None, None)
val suggestionJsonBody = suggestion.toJson
val request = Post(s"$thesaurusapiEndpoint/$coreProjectId/suggestFreeConcept?", suggestionJsonBody)
val res = pipeline(request)
getSuggestedFromFutureHttpResponse(res) match {
case None => ""
case Some(e) => e
}
}
Please, does any one has an idea of what is going on with the implicit marshaller. I though spray Json would come with implicit marshaller.

Answer 1

I assume you already have a custom Json Protocol somewhere so that suggestion.toJson works correctly?
Try the following:
val body = HttpEntity(`application/json`, suggestionJsonBody.prettyPrint)
val request = Post(s"$thesaurusapiEndpoint/$coreProjectId/suggestFreeConcept?", body)
you could also use compactPrint rather than prettyPrint, in either case, it turns the Json into a string containing the json information.

Answer 2

Here is how i solved it:
override def createSuggestedFreeConcepts(suggestedPrefLabels: List[LanguageLiteral], scheme: String, checkDuplicates: Boolean): List[String] = {
import system.dispatcher
import spray.httpx.marshalling._
import spray.httpx.SprayJsonSupport._
val pipeline = addCredentials(BasicHttpCredentials("superadmin", "poolparty")) ~> sendReceive
suggestedPrefLabels map { suggestedPrefLabel =>
val suggestion = SuggestFreeConcept(List(suggestedPrefLabel), checkDuplicates, Some(List(Uri(scheme))), None, None, None, None)
val request = Post(s"$thesaurusapiEndpoint/$coreProjectId/suggestFreeConcept", marshal(suggestion))
val res = pipeline(request)
getSuggestedFromFutureHttpResponse(res) match {
case None => ""
case Some(e) => e
}
}
}
the key is:
import spray.httpx.marshalling._ import spray.httpx.SprayJsonSupport._
and
val request =
Post(s"$thesaurusapiEndpoint/$coreProjectId/suggestFreeConcept",
marshal(suggestion))
I marshall suggestion. The explanation is not super super straightforward. But by fetching around in the doc, it is explained.