swift JSON login REST with post and get response example

Question

It's my first experience with REST in iOS development with swift. I couldn't find any working or straight (simple) example for doing what i need here.

I have a login backend (https://myaddress.com/rest/login), where I need to pass 2 params: login and password. When I pass good values (user exists in database) I get 2 variables as a result: token (string) and firstLogin (bool). So when I get those values I know that login is successful and I can log in into my app.

So I am begging you for an example (just a simple function) of how to achieve that. If I get working code example I will know how to use it for other rest services in my app. I tried many solutions from tutorials I found, but any of them was working for me.. So to not waste my time searching I would like someone experienced to show me the way to achieve that.

I am not sure if Alamofire is so good to use, I know that swift 4 has it's own build neetwork services and to work with json. Any solution that works would be great.

Also, side question - if I would prefer to use Alamofire, do I need to use swiftyJSON also? Or it's just for parsing?

Solution 1

You can use URLSession if you don't like to import Alamofire in your Project to perform a simple task.

here are some method : GET, POST, DELETE METHODS and tutorial

GET METHOD

func makeGetCall() {
  // Set up the URL request
  let todoEndpoint: String = "https://jsonplaceholder.typicode.com/todos/1"
  guard let url = URL(string: todoEndpoint) else {
    print("Error: cannot create URL")
    return
  }
  let urlRequest = URLRequest(url: url)

  // set up the session
  let config = URLSessionConfiguration.default
  let session = URLSession(configuration: config)

  // make the request
  let task = session.dataTask(with: urlRequest) {
    (data, response, error) in
    // check for any errors
    guard error == nil else {
      print("error calling GET on /todos/1")
      print(error!)
      return
    }
    // make sure we got data
    guard let responseData = data else {
      print("Error: did not receive data")
      return
    }
    // parse the result as JSON, since that's what the API provides
    do {
      guard let todo = try JSONSerialization.jsonObject(with: responseData, options: [])
        as? [String: Any] else {
          print("error trying to convert data to JSON")
          return
      }
      // now we have the todo
      // let's just print it to prove we can access it
      print("The todo is: " + todo.description)

      // the todo object is a dictionary
      // so we just access the title using the "title" key
      // so check for a title and print it if we have one
      guard let todoTitle = todo["title"] as? String else {
        print("Could not get todo title from JSON")
        return
      }
      print("The title is: " + todoTitle)
    } catch  {
      print("error trying to convert data to JSON")
      return
    }
  }
  task.resume()
}

POST METHOD

func makePostCall() {
  let todosEndpoint: String = "https://jsonplaceholder.typicode.com/todos"
  guard let todosURL = URL(string: todosEndpoint) else {
    print("Error: cannot create URL")
    return
  }
  var todosUrlRequest = URLRequest(url: todosURL)
  todosUrlRequest.httpMethod = "POST"
  let newTodo: [String: Any] = ["title": "My First todo", "completed": false, "userId": 1]
  let jsonTodo: Data
  do {
    jsonTodo = try JSONSerialization.data(withJSONObject: newTodo, options: [])
    todosUrlRequest.httpBody = jsonTodo
  } catch {
    print("Error: cannot create JSON from todo")
    return
  }

  let session = URLSession.shared

  let task = session.dataTask(with: todosUrlRequest) {
    (data, response, error) in
    guard error == nil else {
      print("error calling POST on /todos/1")
      print(error!)
      return
    }
    guard let responseData = data else {
      print("Error: did not receive data")
      return
    }

    // parse the result as JSON, since that's what the API provides
    do {
      guard let receivedTodo = try JSONSerialization.jsonObject(with: responseData,
        options: []) as? [String: Any] else {
          print("Could not get JSON from responseData as dictionary")
          return
      }
      print("The todo is: " + receivedTodo.description)

      guard let todoID = receivedTodo["id"] as? Int else {
        print("Could not get todoID as int from JSON")
        return
      }
      print("The ID is: \(todoID)")
    } catch  {
      print("error parsing response from POST on /todos")
      return
    }
  }
  task.resume()
}

DELETE METHOD

func makeDeleteCall() {
  let firstTodoEndpoint: String = "https://jsonplaceholder.typicode.com/todos/1"
  var firstTodoUrlRequest = URLRequest(url: URL(string: firstTodoEndpoint)!)
  firstTodoUrlRequest.httpMethod = "DELETE"

  let session = URLSession.shared

  let task = session.dataTask(with: firstTodoUrlRequest) {
    (data, response, error) in
    guard let _ = data else {
      print("error calling DELETE on /todos/1")
      return
    }
    print("DELETE ok")
  }
  task.resume()
}

Solution 2

Thanks @MAhipal Singh for you answer. I'll post here example with Alamafire that I used so it's all in one stack question. It's easier than I though, solutions I tried to use before were not working cause I had problems with pinning certificate about I forgot..

func loginRest(login:String, password:String, deviceId:String){
    let urlStr = restServices.REST_MAIN_URL + restServices.REST_LOGIN
    let params = ["login":login, "password":password, "deviceId":deviceId]
    let paramsJson = try! JSONSerialization.data(withJSONObject: params)

    var headers: HTTPHeaders = ["Content-Type": "application/json"]

  Alamofire.request(urlStr, method: .post, parameters: params, encoding: JSONEncoding.default, headers: headers).responseJSON { (response) in
        switch response.result {
        case .success:
            print("SUKCES with \(response)")
        case .failure(let error):
            print("ERROR with '\(error)")
        }  
    }

If the post is proper the response is (console print):

SUKCES with SUCCESS: {
    firstLogin = 1;
    token = "dfkafjkfdsakfadsjfksjkfaadjfkjdfkjfskjfdkafjakfjakfjsafksjdafjy878328hjh";
}

Comments

[M. Wojcik]

Great. Thanks. Do you maybe know if I can pin SSL certificate (file cert.cer) to url session? I know i can do it with alamofire session manager

[MAhipal Singh]

@M.Wojcik, you can refer these links for SSL Pinning : infinum.co/the-capsized-eight/… and stackoverflow.com/a/34223292/6898523 and gist.github.com/29satnam/a47d9b569204df7fcec4160027a4a0b8