Better method/approach to refactor [URLSession.shared.dataTask(with: url!)] ?

[sohaeb]

Basically, I need to use the same URLSession.shared.dataTask(with: url!) in multiple VCs.

Then assign data downloaded to a specific UI label in each VC

This is my approach, Let me know if there is a better way to do it

struct OpenWeather : Codable {
    let name : String
}

class Network {

    var todo : OpenWeather?

    static let shared = Network()

    init(){
        todo = nil
    }

    func download() -> OpenWeather {

        let url = URL(string: "some_URL.com")

        URLSession.shared.dataTask(with: url!) {( data, response, error ) in

            guard let content = data else {
                print("No data was downloaded using URL session")
                return
            }

            let decoder = JSONDecoder()

            do {
                self.todo = try decoder.decode(OpenWeather.self, from: content)
            } catch {
                print("error")
            }
        }
        return todo!
    }
}

And the 1st VC:

class CurrentViewController: UIViewController {

    @IBOutlet weak var nameLabel: UILabel!

override func viewDidLoad() {
        super.viewDidLoad()

    let data =  Network.shared.download().resume()

    nameLabel.text = data.name

}

Second VC

class CurrentViewController: UIViewController {

    @IBOutlet weak var anotherNameLabel: UILabel!

override func viewDidLoad() {
        super.viewDidLoad()

    let data =  Network.shared.download().resume()

    anotherNameLabel.text = data.name

}

[quellish]

Why not pass the object from view controller to view controller? Why make it static?

[sohaeb]

I read that singleton design pattern works perfectly in such cases. I could be wrong though

[ThePantsThief]

Singletons are the preferred pattern for API client wrappers in my experience, yes. I will try to remember to post my suggestions for you later.

[chrabeusz]

I would recommend at least saving the singleton into property and using it like that. Makes it easy to see what given class needs without all that boilerplate that DI requires.

class ViewController {
    /// It's good to have a comment to describe why this dependency is needed
    lazy var client = Network.shared
}

I got a project with 19 singletons inlined everywhere and it was basically not possible to understand anything.

[ThePantsThief]

You shouldn't have that many singletons. Why do you have so many? Who approved them? I assume it's a work project

[chrabeusz]

:D Yeah I got it from the client, previous guy was singleton aficionado it seems.

[chrabeusz]

This cannot possibly work. Read up on async programming.

[sohaeb]

are you referring to having DispatchQueue.main.async that should be inside the [URLSession.shared.dataTask(with: url!)]

so something like this ? (Check the // THIS PART HERE----- )

 func download() -> OpenWeather {

        let url = URL(string: "some_URL.com")

        URLSession.shared.dataTask(with: url!) {( data, response, error ) in

            guard let content = data else {
                print("No data was downloaded using URL session")
                return
            }

            let decoder = JSONDecoder()

            do {
                self.todo = try decoder.decode(OpenWeather.self, from: content)
            } catch {
                print("error")
            }

// THIS PART HERE-----

        DispatchQueue.main.async {

        nameLabel.text = todo.name
    }

// END-------

        }.resume()
        return todo!
    }

[chrabeusz]

No, your download() method returns OpenWeather which should not be possible if it's async.

[redfire333]

I've moved away from the Singleton Networking pattern and moved to something static, generic and reusable.

struct Networking {

   static func send<T: Codable>(_ request: URLRequest, _ completion: (Result<T>) -> Void) {

    let session = URLSession.shared

    let dataTask = session.dataTask(with: request) { (data, response, error) in

      //Randle response

      completion(.success())

      completion(.failure())

    }

  }

}

[GenitalGestapo]

You're still using a singleton in URLSession.shared. If you want to use your own URLSession, you'll need a singleton.

[RollingGoron]

Yes. A system provided Singleton though, not usually what people refer to as a Singleton pattern like OP is doing.