I'm having troubles with my Login authentication - json

Question

I have a JSON Post authentication to make a login request, of course I need to send the user & password parameters to receive a response for filling my HomeViewController, so I need first to validate the two parameters, and if the user doesn't exist of course I'm going to send an Alert and forbid the access to the Home. The thing is that I don't know in which method do I have to put this validation, because the way I'm doing it throws me an alert before the validation. This is my code:
class LoginViewController: UIViewController, LoginProtocol {
#IBOutlet weak var username: UITextField!
#IBOutlet weak var password: UITextField!
#IBOutlet weak var activityIndicator: UIActivityIndicatorView!
var user : String = ""
var psw : String = ""
var idResponse : String = ""
var message : String = ""
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func validateLogin(_ sender: Any) {
DoLogin(self.username.text!, self.password.text!)
}
#IBAction func login(_ sender: Any) {
if self.idResponse != "0" {
validation(message: self.message)
} else {
let vc = self.storyboard!.instantiateViewController(withIdentifier: "home") as! HomeViewController
self.present(vc, animated: false, completion: nil)
vc.getUser = self.username.text!
vc.getPassword = self.password.text!
}
}
func validation(message: String) {
let myAlert = UIAlertController(title: "Alert", message: message, preferredStyle: UIAlertControllerStyle.alert)
let okAction = UIAlertAction (title: "Ok", style: UIAlertActionStyle.default, handler: nil)
myAlert.addAction(okAction)
self.present(myAlert, animated: true, completion: nil)
return
}
func DoLogin(_ user:String, _ psw:String)
{
let url = URL(string: "http://162.209.99.39:8080/MiClaroBackend/auth")
let session = URLSession.shared
let request = NSMutableURLRequest(url: url!)
request.httpMethod = "POST"
self.username.text = user
self.password.text = psw
let paramToSend = ["username":user,"password":psw]
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
request.httpBody = try! JSONSerialization.data(withJSONObject: paramToSend)
let task = session.dataTask(with: request as URLRequest, completionHandler: {
(data, response, error) in
guard let _:Data = data else
{
return
}
let json:AnyObject?
do {
json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary
if let parseJSON = json{
let loginModel = LoginModel()
let defaultServiceResponse = parseJSON["defaultServiceResponse"] as! NSDictionary
loginModel.message = defaultServiceResponse["message"] as! String
loginModel.idResponse = defaultServiceResponse["idResponse"] as! Int
self.idResponse = String(loginModel.idResponse)
self.message = loginModel.message
print(json!)
}
} catch {
let error = ErrorModel()
error.phrase = "PARSER_ERROR"
error.code = -1
error.desc = "Parser error in login action"
}
})
task.resume()
}
The validateLogin method is attached to a TextView with the action: "EditingDidEnd". So what I need is that when I finish writing the password, the DoLogin function validates that exists and let me continue to the HomeViewController, but the issue is that when I click the button 'Ingresar'(Login), it shows a blank Alert first and only the second time I click the button it let me through immediately. I don't know why is sending the Alert that I declare at the "func validation" if I'm not calling it before. I'm going to attach a picture to show you the Alert that is appearing:

Answer 1

Chances are your EditingDidEnd method calls DoLogin which is processing in background when you press the Login button. hence your if condition below becomes true as your idResponse is initialized to "" empty string.
if self.idResponse != "0"
Rectify this if condition to check if its empty then dont call the validation message.
The best way to do this is to call your DoLogin only after click of the Login button and if in case you have success redirect to Home page. Otherwise show the alert. Please note do the UI action on the main thread.

Answer 2

First Update the Code And User Like this
func DoLogin(_ user:String, _ psw:String)
{
let url = URL(string: "http://162.209.99.39:8080/MiClaroBackend/auth")
let session = URLSession.shared
let request = NSMutableURLRequest(url: url!)
request.httpMethod = "POST"
let paramToSend = ["username":user,"password":psw]
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
request.httpBody = try! JSONSerialization.data(withJSONObject: paramToSend)
let task = session.dataTask(with: request as URLRequest, completionHandler: {
(data, response, error) in
guard let _:Data = data else
{
return
}
let json:AnyObject?
do {
json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary
if let parseJSON = json{
let loginModel = LoginModel()
let defaultServiceResponse = parseJSON["defaultServiceResponse"] as! NSDictionary
loginModel.message = defaultServiceResponse["message"] as! String
loginModel.idResponse = defaultServiceResponse["idResponse"] as! Int
self.idResponse = String(loginModel.idResponse)
self.message = loginModel.message
if self.idResponse != "0" {
validation(message: self.message)
} else {
let vc = self.storyboard!.instantiateViewController(withIdentifier: "home") as! HomeViewController
self.present(vc, animated: false, completion: nil)
vc.getUser = user!
vc.getPassword = psw!
}
}
} catch {
let error = ErrorModel()
error.phrase = "PARSER_ERROR"
error.code = -1
error.desc = "Parser error in login action"
}
})
task.resume()
}

Answer 3

If You want to add alert in imageview use this code
var imageView = UIImageView(frame: CGRectMake(220, 10, 40, 40))
imageView.image = yourImage
alert.view.addSubview(imageView)