How to choose different object based on the JSON content

[SirStone]

Hi
Pretty new to NIM so It's likely that I'm missing some information that I can't see in the doc but is there. Whit this premisis here my question:
I have a JSON message received and I need to convert it to an object between several ones, for example "MessageType1" and "MessageType2"; the information if the JSON message is of type1 or type2 is written inside it, in a specific string field.
How can I convert the JSON message to the right object with jsony in the fastest way?

Thanks in advance

[treeform]

You can use a case object like here:

import jsony, json

type
  MessageKind = enum
    MessageType1
    MessageType2

  Message = object
    case kind: MessageKind
    of MessageType1:
      cat: string
      mews: int
    of MessageType2:
      dog: string
      barks: int

echo """{"kind":"MessageType1", "cat": "barsik", "mews": 2}""".fromJson(Message)
echo """{"kind":"MessageType2", "dog": "sharik", "barks": 1}""".fromJson(Message)

Or you can parse just the header part of the message first and then and handle messages as a separate things.

import jsony, json

type
  MessageHeader = object
    kind: string
  MessageA = object
    cat: string
    mews: int
  MessageB = object
    dog: string
    barks: int

proc handleMessage(data: string) =
  let kind = data.fromJson(MessageHeader).kind
  if kind == "MessageType1":
    echo data.fromJson(MessageA)
  if kind == "MessageType2":
    echo data.fromJson(MessageB)

"""{"kind":"MessageType1", "cat": "barsik", "mews": 2}""".handleMessage()
"""{"kind":"MessageType2", "dog": "sharik", "barks": 1}""".handleMessage()

I hope that helps.