Is there a way to get lift-json to auto-convert numeric string fields to numeric type?

Question

I'm using lift-json to deserialize simple objects from a POST request. Example:

{"id": "35", "name": "My topic", "slug": "my-slug", "imageUrl": "http://foo.bar/image.png"}

class definition:

class Topic(var id: Option[Long], var name: String, val slug: String, val imageUrl: String) 

Then I use

read[Topic](jsonString)

Is it possible to get json-lift to read the id as a Long automatically?

Answer 1

You can do it by converting the JSON.

val json = parse("""{"id": "35", "name": "My topic", ...}""")
json transform { case JField("id", JString(s)) => JField("id", JInt(s.toInt)) }

And then extract a case class from that transformed JSON.