Swifty Json parsing - ios

Question

I am using SwiftyJson library for parsing my following json
{
"data": {
"id": "12345",
"messages": {
"message": "{\"data\":{\"msg\":\"HelloMsg\"}}"
}
}
}
I tried to use following code to get msg parameter
let json = JSON(data)
let msg = JSON(json["data"]["messages"]["message"])
msg["data"]["msg"].stringValue
However, I could not get the value of msg parameter. What shall I do to get HelloMsg?

Answer 1

The content of the "message" field is not parsed JSON, it's a JSON string.
Use SwiftyJSON's JSON(parseJSON:) initializer to accept a string as input and parse it as JSON:
let messages = json["data"]["messages"]["message"].stringValue
let innerJSON = JSON(parseJSON: messages)
let msg = innerJSON["data"]["msg"].stringValue // "HelloMsg"

Answer 2

The error occurs because JSON(...) is the wrong API to initialize and parse a SwiftyJSON object from a string.
You have to use this syntax:
let json = JSON(data)
let msg = JSON(parseJSON: json["data"]["messages"]["message"].stringValue)
msg["data"]["msg"].stringValue
From the documentation of init(_ object: Any):
note: this does not parse a String into JSON, instead use init(parseJSON: String)
Edit:
To test the code in a Playground
let str = """
{"data": {"id": "12345",
"messages": {
"message": "{\\"data\\":{\\"msg\\":\\"HelloMsg\\"}}"
}
}
}
"""
let data = Data(str.utf8)
let json = JSON(data)
let msg = JSON(parseJSON: json["data"]["messages"]["message"].stringValue)
msg["data"]["msg"].stringValue
The JSON as traditional literal string is
let str = "{\"data\": {\"id\": \"12345\",\"messages\": {\"message\": \"{\\\"data\\\":{\\\"msg\\\":\\\"HelloMsg\\\"}}\"}}}"

Answer 3

The messaage is a string. not a JSON. so SwiftyJson could not parse it. You will have to first parse that string and than get the message from that using JSONSerialization.jsonObject(with: Data, options: JSONSerialization.ReadingOptions).
You can refer to this answer to get the dictionary from that string: https://stackoverflow.com/a/30480777/7820107

Answer 4

Your second "message" key value is a String with a dictionary in JSON format, so you need to convert that string to JSON and access to ["data"]["msg"] then
Code
let json = JSON(data)
let msg = json["data"]["messages"]["message"]
let jsonFromString = JSON(data: msg.data(using: .utf8)!, options: JSONSerialization.ReadingOptions.allowFragments, error: nil)
debugPrint(jsonFromString["data"]["msg"])
Output
HelloMsg