How to edit existing JSON object with sprayJSON

Question

I am using akka with spray json support for which I need to edit value in the recieved json.

import akka.http.scaladsl.server.Directives
import akka.http.scaladsl.marshallers.sprayjson.SprayJsonSupport
import spray.json._


final case class Item(name: String, id: Long)
final case class Order(items: List[Item],orderTag:String)


trait JsonSupport extends SprayJsonSupport with DefaultJsonProtocol {
  implicit val itemFormat = jsonFormat2(Item)
  implicit val orderFormat = jsonFormat2(Order)
}

In my use case I recieve the json with orderTag value as null, all I need to do is edit the orderTag value with and then use it as entity value.Is it possible to write/edit jsonObject and How to do that ?

class MyJsonService extends Directives with JsonSupport {

  // format: OFF
  val route =
    get {
      pathSingleSlash {
        complete(Item("thing", 42)) // will render as JSON
      }
    } ~
    post {
      entity(as[Order]) { order => // will unmarshal JSON to Order
        val itemsCount = order.items.size
        val itemNames = order.items.map(_.name).mkString(", ")
        complete(s"Ordered $itemsCount items: $itemNames")
      }
    }

}

score 0 · Answer 1 · answered May 14 '17 at 08:52

You can just edit the json AST like ..

val json = """{"orderTag":null}"""
val jsVal = json.parseJson
val updatedJs = if (jsObj.fields.get("orderTag") == Some(JsNull)) {
JsObject(jsObj.fields + ("orderTag" -> JsString("new tag")))
} else {
    jsObj
}
updatedJs.compactPrint
res26: String = """
 {"orderTag":"new tag"}
"""

How to edit existing JSON object with sprayJSON

1 Answers1