Alamofire async call

Question

I have a simple problem. I'm connecting to my RESTful server and trying to connect. I do get a response and everything works perfect, however when I try to call a function to set a variable, it just doesn't call it.

Code:

//
//  LoginClass.swift
//  LoginApp
//
//  Created by Tarek Adel on 12/3/16.
//  Copyright © 2016 Tarek Adel. All rights reserved.
//

import Foundation
import Alamofire;
import UIKit;

class LoginClass {
    var result: Bool = false;

    var username: String
    var password: String

    init(username: String, password:String) {
        self.username = username;
        self.password = password;
    }


    func login() -> Void {
        let data = [
            "grant_type" : "password",
            "username" : self.username,
            "password" : self.password,
            "client_secret":"xxxxxx",
            "client_id":"xxxxxx",
            "scope": ""
        ]
        Alamofire.request("http://localhost:8000/oauth/token", method: .post, parameters: data)
            .responseJSON { response in

                //to get status code
                if let status = response.response?.statusCode {
                    switch(status){
                    case 200:
                        self.loginSuccess();
                    default:
                        print("error with response status: \(status)")
                    }
                }
                //to get JSON return value

                if let result = response.result.value {
                    let JSON = result as! NSDictionary
                    print(JSON)
                }

        }
    }

    func loginSuccess() {
        self.result = true;
    }

}

This is where I check the self.result :

@IBAction func loginButton(_ sender: UIButton) {
    let username = usernameTextField.text!;
    let password = passwordTextField.text!;

    let loginClass = LoginClass(username: username, password:password)
    loginClass.login()

    if(loginClass.result == true) {
        resultLabel.text = "Correct!"
    } else {
        resultLabel.text = "Wrong Credentials"
    }

}

Why are you thinking that it is not executing that function, have you put breakpoint inside that function and trying to debug it? — Nirav D, Dec 03 '16 at 10:44
Agreed with Nirav. I'm assuming you're having trouble calling `self.loginSuccess` inside of the switch statement. Are you sure that `status` is getting set in the optional binding above? — Kevin Aleman, Dec 03 '16 at 10:47
yes, I have checked that it calls the self.loginSuccess but the self.result never changes — Tarek Adel, Dec 03 '16 at 10:48
Can you show us your code where you check for the value of `self.result`? — Kevin Aleman, Dec 03 '16 at 11:02
@TarekAdel You are always getting false because `login` method is making an async call so that `self.result = true` is executing later when you get your response and that if condition of your execute before of that. — Nirav D, Dec 03 '16 at 11:13
I think that may be the case, but do you have any idea on how to fix it? — Tarek Adel, Dec 03 '16 at 11:18

score 4 · Accepted Answer · answered Dec 03 '16 at 11:22

You need to use completion handler with your login method because it is making an Async call, so make one completionHandler with your login method and than execute that if condition inside that completionHandler.

func login(completionHandler: (_ result: Bool) -> ()) {
    let data = [
        "grant_type" : "password",
        "username" : self.username,
        "password" : self.password,
        "client_secret":"xxxxxx",
        "client_id":"xxxxxx",
        "scope": ""
    ]
    Alamofire.request("http://localhost:8000/oauth/token", method: .post, parameters: data)
        .responseJSON { response in

            //to get status code
            if let status = response.response?.statusCode {
                switch(status){
                case 200:
                    //to get JSON return value
                    if let result = response.result.value {
                        let JSON = result as! NSDictionary
                        print(JSON)
                    }
                    completionHandler(true)
                default:
                    print("error with response status: \(status)")
                    completionHandler(false)
                }
            }                
    }
}

Now call this login method like this.

self.login { (result) in
    if(result)
    {
        resultLabel.text = "Correct!"
    }
    else{
        resultLabel.text = "Wrong Credentials"
    }
}

Note: If you want JSON response also then make completion handler with two parameter Bool and Dictionary and pass JSON also with that.

Thanks a lot, this really helped – Tarek Adel Dec 03 '16 at 11:33 — Tarek Adel, Dec 03 '16 at 11:33

Alamofire async call

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