I want to transform a json with underscore case keys to camel case keys.
"{\"first_key\": \"first_value\", \"second_key\": {\"second_first_key\":\"second_first_value\"}}"
to
"{\"firstKey\": \"first_value\", \"secondKey\": {\"secondFirstKey\":\"second_first_value\"}}"
This is partial code:
val CamelCaseRegex = new Regex("(_.)")
val jsonTransformer = (__).json.update(
//converts json camel_case field names to Scala camelCase field names
)
val jsonRet = Json.parse(jsonStr).transform(jsonTransformer)
I have tried several ways in the update method without success.
While it would be nice to do this with just the native Play library, it's a good use-case for Mandubian's Play Json Zipper extension libraries.
Here's a quick go at this (not exhaustively tested). First you need to add the resolver and library to your build:
resolvers += "mandubian maven bintray" at "http://dl.bintray.com/mandubian/maven"
libraryDependencies ++= Seq(
"com.mandubian" %% "play-json-zipper" % "1.2"
)
Then you could try something like this:
import play.api.libs.json._
import play.api.libs.json.extensions._
// conversion function borrowed from here:
// https://gist.github.com/sidharthkuruvila/3154845
def underscoreToCamel(name: String) = "_([a-z\\d])".r.replaceAllIn(name, {m =>
m.group(1).toUpperCase
})
// Update the key, otherwise ignore them...
// FIXME: The None case shouldn't happen here so maybe we
// don't need it...
def underscoreToCamelCaseJs(json: JsValue) = json.updateAllKeyNodes {
case (path, js) => JsPathExtension.hasKey(path) match {
case Some(key) => underscoreToCamel(key) -> js
case None => path.toJsonString -> js
}
}
Which on this input:
val testJson = Json.obj(
"some_str" -> JsString("foo_bar"),
"some_obj" -> Json.obj(
"some_field" -> Json.arr("foo", "bar")
),
"an_int" -> JsNumber(1)
)
...produces:
{
"someStr" : "foo_bar",
"someObj" : {
"someField" : [ "foo", "bar" ]
},
"anInt" : 1
}
For your requirement, you can use this library play-json-naming . It easily converts snake_case
(underscore case) json to camelCase
and vice versa. https://github.com/tototoshi/play-json-naming
If you're using play >= 2.6:
final case class Blah(foo: String)
object Blah {
import play.api.libs.json._
implicit val config = JsonConfiguration(SnakeCase)
implicit val blahReader:OFormat[QueueMsgEnvelope] = Json.format[Blah]
}
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