gistfile1.scala

import argonaut._, Argonaut._

case class Message ( id:String , event:String, data:Json )

object Message {
  implicit val messageCodec = casecodec3( Message.apply , Message.unapply )( "id" , "event" , "data" )
  
  //scala> """{"id":"foo","event":"bar","data":"string"}""".decodeOption[Message]
  //res1: Option[Message] = Some(Message(foo,bar,"string"))

  //scala> """{"id":"foo","event":"bar","data":{"sub":"string"}}""".decodeOption[Message]
  //res2: Option[Message] = Some(Message(foo,bar,{"sub":"string"}))
}