Scala reads object with nested optional property - json

Question

I'm trying to write a reads for the following class
case class User(id: String, imageId: Option[String])
The JSON I have looks like this:
{
"id": 1
"image": { "id" : 2 }
}
However the 'image' field may not exist, or it may be null.
My reads looks like this:
implicit val userReader: Reads[User] = (
(JsPath \ "id").read[String] and
(JsPath \ "image" \ "id").readNullable[String]
) (User.apply _)
But this does not seem to work, I still get an error when it finds a sample with no image. 'ValidationError [...] error.path.missing [...] /image/id'
How can this be solved? I'd prefer not to create an Image class, which I'm not going to use anywhere.

Answer 1

I think the issue comes from the fact that you are trying to read a String whereas id is an Int. You should mind your types in your json / reader.
Two options
if id is really an Int, read it as an Int
if id is a String, change your JSON
If you still want to have a String in your case class, you can do :
(JsPath \ "image" \ "id").readNullable[Int].map(_.toString)

Answer 2

You forgot a comma between the two elements ("id" and "image"). That's why the /image/id path seems to be missing for the parser.
There are all sorts of tools for validating a JSON structure, for instance https://jsonlint.com/ .
So your JSON structure should look like this:
{
"id": 1,
"image": {
"id": 2
}
}

Answer 3

i may be late but here is a workaround:
implicit val userReader: Reads[User] = (
(JsPath \ "id").read[String] and
(JsPath \ "image" \ "id").readNullable[String].orElse((__ \ "dummy").readNullable[String])
) (User.apply _)
Not perfect but it work well
better solution would be to directly cast the Js Reads(JsSuccess(None:Option[Int])) inside the orElse but i haven't been able to do it...