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scalasprayjson4s

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

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

Solution

  • 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.