parsing invalid JSON Swift 4

Question

My Json looks like this:

data = { "key":"value",
         "key":"value",
         "key":"value"}

I've been trying to use Swift4 Codable protocols for parsing JSON and have used it to great effect but for the life of me I cannot break this structure. The outer data = makes it invalid JSON but I can't seem to find any way to modify the data before I attempt to pass it to the JSONDecoder.

Is there any way I can just receive that data as a string so I can drop the outermost characters and just parse the remaining JSON object?

Answer 1

If JSON serialization is failing and you want to correct the malformed data (and fixing the API response isn't an option) you can convert the data to a string, modify the string to create valid JSON, then convert back to data and decode that into your model object. For the case above:

func normalizeJSON(data: Data) -> Data? {
    guard let stringRepresentation = String(data: data, encoding: .utf8) else { return nil }

    let validJSONString = stringRepresentation.dropFirst(6)

    return validJSONString.data(using: .utf8)
}

Answer 2

func parseSomeUrl {

    let someUrl = "http://api.someurl.com"

    guard let url = URL(string: someUrl) else {return}

    URLSession.shared.dataTask(with: url) {(myResponse, response, err) in

        guard let data = data else {return}

        do {
            let data = try JSONDecoder().decode(myResponse.self, from: data)
        }
    } catch let jsonErr {
        print("Error serializing json:", jsonErr)
    }
}.resume()