Parse JSON with unknown attributes names into a Case Class - json

Question

I have the following JSON file to be parsed into a case class:
{
"root": {
"nodes": [{
"id": "1",
"attributes": {
"name": "Node 1",
"size": "3"
}
},
{
"id": "2",
"attributes": {
"value": "4",
"name": "Node 2"
}
}
]
}
}
The problem is that the attributes could have any value inside it: name, size, value, anything ...
At this moment I have defined my case classes:
case class Attributes(
name: String,
size: String,
value: Sting
)
case class Nodes(
id: String,
attributes: Attributes
)
case class Root(
nodes: List[Nodes]
)
case class R00tJsonObject(
root: Root
)
Whats is the best way to deal with this scenario when I can receive any attribute ?
Currently I am using Json4s to handle son files.
Thanks!

Answer 1

Your attributes are arbitrarily many and differently named, but it seems you can store them in a Map[String, String] (at least, if those examples are anything to go by). In this case, using circe-parser (https://circe.github.io/circe/parsing.html), you could simply use code along these lines in order to convert your JSON directly into a simple case-class:
import io.circe._, io.circe.parser._
import io.circe.generic.semiauto._
case class Node(id: String, attributes: Map[String,String])
case class Root(nodes: List[Node])
implicit val nodeDecoder: Decoder[Node] = deriveDecoder[Node]
implicit val nodeEncoder: Encoder[Node] = deriveEncoder[Node]
implicit val rootDecoder: Decoder[Root] = deriveDecoder[Root]
implicit val rootEncoder: Encoder[Root] = deriveEncoder[Root]
def myParse(jsonString: String) = {
val res = parse(jsonString) match {
case Right(json) => {
val cursor = json.hcursor
cursor.get[Root]("root")
}
case _ => Left("Wrong JSON!")
}
println(res)
}
This snippet will print
Right(Root(List(Node(1,Map(name -> Node 1, size -> 3)), Node(2,Map(value -> 4, name -> Node 2)))))
on the console, for the JSON, you've given. (Assuming, the solution doesn't have to be in Json4s.)