how to use spray json4s support to marshal json data as snake case

Question

Scala case class fields are camelcased,

but I want to produce json with snake case.

Is there anyway to do this ?

The Json4sSupport trait seems have no way to do this

Answer 1

A JValue has a snakizeKeys function.

import org.json4s.jackson.JsonMethods._

val json = """{
             |  "lowerCamelCase": 100,
             |  "UpperCamelCase": 100,
             |  "snake_case": 100,
             |  "dashed-case": 100,
             |  "using spaces": 100
             |}""".stripMargin

val ast = parse(json)

println(pretty(ast.snakizeKeys))

//  {
//    "lower_camel_case" : 100,
//    "upper_camel_case" : 100,
//    "snake_case" : 100,
//    "dashed_case" : 100,
//    "using_spaces" : 100
//  }

You probably want to hook the conversion in a post-processing step on the response and/or pre-processing of the request.