sureshmopidevi / NetworkDelegation

Basic usage of Delegates in Network Calls.

🌐 Networking with Protocols

Output

Basic usage of Delegates in Network Calls.

1. Create a Protocol for listening events occuring in Network functions.

protocol NetworkDelegate {
    func didStartedAPICall()
    func didFailedToGetResponse(error: String)
    func didReceivedResponse(response: String)
    func didEndAPICall()
}

2. Create a Singleton class NetworkManager to manage networking in application.

• Add delegate property to assign NetworkDeleagate properties.

class NetworkManager {
    private init() {}
    var delegate: NetworkDelegate?
    static let shared = NetworkManager()

    func fetch(urlString: String = "https://jsonplaceholder.typicode.com/users") {
        delegate?.didStartedAPICall()
        DispatchQueue.global(qos: .background).async {
            URLSession.shared.dataTask(with: URL(string: urlString)!) { data, _, err in
                if let error = err {
                    self.delegate?.didFailedToGetResponse(error: error.localizedDescription)
                }
                if let response = data, let asString = String(data: response, encoding: .utf8) {
                    self.delegate?.didReceivedResponse(response: asString)
                }
                self.delegate?.didEndAPICall()
            }.resume()
        }
    }
}

3. Conform to the NetworkDelegate in your desired View.

struct ContentView: View {
    @State var data: [String] = ["😊"]

    var body: some View {
        NavigationView {
          ...
            .navigationBarTitle("Delegate Pattern").onAppear {
                NetworkManager.shared.delegate = self
            }
        }
    }
}

4. Make Network call when tapping on buttons

• Here we are making two calls
  1. Success Call with GET SUCCESS RESPONSE Button
  2. Failure Call with GET FAILED RESPONSE Button

Button("GET SUCCESS RESPONSE") {
      self.data.removeAll()
       NetworkManager.shared.fetch()
  }

Button("GET FAILED RESPONSE") {
      self.data.removeAll()
      NetworkManager.shared.fetch(urlString: "2398")
   }

5. Add the delegate functions and confirm to view

extension ContentView: NetworkDelegate {
    func didReceivedResponse(response: String) {
        data.append("✅ GOT RESPONSE \n\(response)")
    }

    func didStartedAPICall() {
        data.append("🎬 API CALL STARTED")
    }

    func didFailedToGetResponse(error: String) {
        data.append("🛑 API CALL ENDED WITH ERROR \n\(error)")
    }

    func didEndAPICall() {
        data.append("🤞 FINISHED API CALL")
    }
}