Conforming JSON response to struct and array Swift

Question

Currently, I have a Struct called User, which defines the variables I want to decode from the HTTP response. Then, I have an array called users which will contain the response. As you can see, I populate users in the random8 function, but now in the random1 function I am having problems. In the random1 function, I only get 1 user instead of 8, and I am trying to take that data and replace one of the current users with that new data. I am able to do that successfully in my code (by extracting each value), but I am pretty sure I am not doing it the standard way. Please let me know if there is a better way to do this.

Keep in mind, random8 is called on viewDidLoad, and random1 occurs later on when they tap a specific button, so I am replacing the data of one specific index of users.

 struct User: Decodable {
    var id: Int
    var first_name: String
    var last_name: String
    var picture_url: String
    var points: Int
    var school: String
    var grade: Int
}

 var users = [User]()

func getRandom8() {
    let url = URL(string: "https://somewebsite.com/users/random/eight")
    let session = URLSession.shared

    let request = NSMutableURLRequest(url: url!)
    let preferences = UserDefaults.standard
    request.addValue("JWT \(preferences.object(forKey: "token") as! String)", forHTTPHeaderField: "Authorization")
    request.setValue("application/json", forHTTPHeaderField: "Content-Type")
    request.httpMethod = "GET"

    let task = session.dataTask(with: request as URLRequest, completionHandler: {
        (data, response, error) in
        do {
            self.users = try JSONDecoder().decode([User].self, from: data!)

            DispatchQueue.main.async (
                execute: self.loadRandom8
            )

        } catch {
            print("error in getting data")
        }
    })

    task.resume()

}

func getRandom1(index:Int) {
    let url = URL(string: "https://somewebsite.com/users/random/one")
    let session = URLSession.shared

    let request = NSMutableURLRequest(url: url!)
    let preferences = UserDefaults.standard
    request.addValue("JWT \(preferences.object(forKey: "token") as! String)", forHTTPHeaderField: "Authorization")
    request.setValue("application/json", forHTTPHeaderField: "Content-Type")
    request.httpMethod = "GET"
    //write a statement that says if that user is already there, do the call again
    let task = session.dataTask(with: request as URLRequest, completionHandler: {
        (data, response, error) in

        do {
            let responseObject = (try? JSONSerialization.jsonObject(with: data!)) as? [String: Any]
            print(responseObject)

            let indexFirstName = responseObject?.index(forKey: "first_name")
            let indexId = responseObject?.index(forKey: "id")
            let indexPictureURL = responseObject?.index(forKey: "picture_url")
            let indexPoints = responseObject?.index(forKey: "points")
            let indexSchool = responseObject?.index(forKey: "school")
            let indexGrade = responseObject?.index(forKey: "grade")
            let indexLastName = responseObject?.index(forKey: "last_name")

            self.users[index].last_name = responseObject![indexLastName!].value as! String
            self.users[index].first_name = responseObject![indexFirstName!].value as! String
            self.users[index].id = responseObject![indexId!].value as! Int
            self.users[index].picture_url = responseObject![indexPictureURL!].value as! String
            self.users[index].points = responseObject![indexPoints!].value as! Int
            self.users[index].school = responseObject![indexSchool!].value as! String
            self.users[index].grade = responseObject![indexGrade!].value as! Int


            DispatchQueue.main.async (
                execute: self.loadRandom8
            )

        } catch {
            print("error in getting data")
        }
    })

    task.resume()

}

Why does the implementation of getRandom1 not use JSONDecoder? Why do you create all of those indexFirstName, indexId, etc. variable and then ignore them? — rmaddy
– rmaddy, Commented Jul 7, 2018 at 15:50
I didn't know what to decode it to, since it would try decoding to an array, which doesn't work since there is only one response. — Levi
– Levi, Commented Jul 7, 2018 at 15:54
Please post your new question as a new question, not an edit to this one. — rmaddy
– rmaddy, Commented Jul 7, 2018 at 16:07

Gereon · Accepted Answer · 2018-07-07 16:04:12Z

1

Without seeing the JSON format you're getting in the random/one request it's a little hard to say, but you should be able to parse a single User instance using

let user = try JSONDecoder().decode(User.self, from: data!)

instead of resorting to JSONSerialization

and to put the data into the users array, do users[index] = user

edited Jul 7, 2018 at 16:04

answered Jul 7, 2018 at 15:50

Gereon

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3 Comments

Levi Over a year ago

Now how do I get the contents of user into the specific index of users? I need the data for example to replace users[2]

rmaddy Over a year ago

users[2] = user.

Levi Over a year ago

I will try that, I did something similar and it didn't work, but I will try again. I will let you know in a minute if it works

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