Can't connect swift app to MySQL

Question

I'm developing an iOS app using Swift 2. I want the login info (user and password) to be stored in a MySQL database online, which is in a godaddy VPS server. This is the class for registration:

import UIKit

class RegisterPageViewController: UIViewController {

    @IBOutlet weak var userEmailTextField: UITextField!
    @IBOutlet weak var userPasswordTextField: UITextField!
    @IBOutlet weak var repeatPasswordTextField: UITextField!
    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    @IBAction func registerButtonTapped(sender: AnyObject) {

        let userEmail = userEmailTextField.text
        let userPassword = userPasswordTextField.text
        let userRepeatPassword = repeatPasswordTextField.text

        //Check for empty fields
        if(userEmail!.isEmpty || userPassword!.isEmpty || userRepeatPassword!.isEmpty) {

            //Display alert message
            displayMyAlertMessage("Todos los campos son requeridos")
            return
        }
        //Check if password match
        if(userPassword != userRepeatPassword) {
            //Display an alert message
            displayMyAlertMessage("Passwords no coinciden")
            return
        }

        //Send user data to server side
        let myURL = NSURL(string: "https://gastonberenstein.com/pruebasmysql/userRegister.php")
        let request = NSMutableURLRequest(URL: myURL!)
    request.HTTPMethod = "POST"

    let postString = "email=\(userEmail)&password=\(userPassword)"
    request.HTTPBody = postString.dataUsingEncoding(NSUTF8StringEncoding)

    let task = NSURLSession.sharedSession().dataTaskWithRequest(request) {
        data, response, error in

        if error != nil {
            print("error=\(error)")
        }

        do {
            var json = try NSJSONSerialization.JSONObjectWithData(data!, options: .MutableContainers) as? NSDictionary

            if let parseJSON = json {
                var resultValue = parseJSON["status"] as! String!
                print("result: \(resultValue)")

                var isUserRegistered:Bool = false
                if(resultValue == "Success") {
                    isUserRegistered = true
                }

                var messageToDisplay:String = parseJSON["message"] as! String
                if(!isUserRegistered) {
                    messageToDisplay = parseJSON["message"] as! String
                }

                dispatch_async(dispatch_get_main_queue(), {

                    //Display alert message with confirmation
                    var myAlert = UIAlertController(title: "Alert", message: messageToDisplay, preferredStyle: UIAlertControllerStyle.Alert)

                    let okAction = UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default){ action in
                        self.dismissViewControllerAnimated(true, completion: nil)
                    }
                    myAlert.addAction(okAction)
                    self.presentViewController(myAlert, animated: true, completion: nil)
                })
            }
        } catch {
            print(error)
        }
    }
    task.resume()
}

func displayMyAlertMessage(userMessage:String) {
    var myAlert = UIAlertController(title:"Alert", message: userMessage, preferredStyle: UIAlertControllerStyle.Alert)

    let okAction = UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default, handler: nil)
    myAlert.addAction(okAction)

    self.presentViewController(myAlert, animated: true, completion: nil)
}

}

Conn.php:

<?php
  class Conn {
     public static $dbhost = "166.62.92.31";
     //public static $dbhost = "localhost"
     public static $dbuser = "gastonbe_gaston";
     public static $dbpass = "xxx";
     public static $dbname = "gastonbe_pruebasmysql";
  }
?>

MySQLDao.php:

<?php
class MySQLDao {
    var $dbhost = null;
    var $dbuser = null;
    var $dbpass = null;
    var $conn = null;
    var $dbname = null;
    var $result = null;

    function __construct() {
        $this->dbhost = Conn::$dbhost;
        $this->dbuser = Conn::$dbuser;
        $this->dbpass = Conn::$dbpass;
        $this->dbname = Conn::$dbname;
    }

    public function openConnection() {
        $this->conn = new mysqli($this->dbhost, $this->dbuser, $this->dbpass, $this->dbname);
        if (mysqli_connect_errno())
            echo new Exception("No se pudo establecer la conexion a la base de datos");
    }

    public function getConnection() {
        return $this->conn;
    }

    public function closeConnection() {
        if ($this->conn != null)
            $this->conn->close();
    }

    public function getUserDetails($email) {
        $returnValue = array();
        $sql = "select * from users where user_email='" . $email . "'";
        $result = $this->conn->query($sql);
        if ($result != null && (mysqli_num_rows($result) >= 1)) {
            $row = $result.fetch_array(MYSQLI_ASSOC);
            if (!empty($row)) {
                $returnValue = $row;
            }
        }
        return $returnValue;
    }

    public function getUserDetailsWithPassword($email, $userPassword) {
        $returnValue = array();
        $sql = "select id, user_email from users where user_email='" . $email . "' and user_password='" .$userPassword . "'";
        $result = $this->conn->query($sql);
        if ($result != null && (mysqli_num_rows($result) >=1)) {
            $row = $result->fetch_array(MYSQLI_ASSOC);
            if (!empty($row)) {
                $returnValue = $row;
            }
        }
        return $returnValue;
    }

    public function registerUser($email, $password) {
        $sql = "insert into users set user_email=?, user_password=?";
        $statement = $this->conn->prepare($sql);
        if (!$statement)
            throw new Exception($statement->error);
        $statement->bind_param("ss", $email, $password);
        $returnValue = $statement->execute();
        return $returnValue;
    }
}
?>

registerUser.php:

    <?php
   require("Conn.php");
   require("MySQLDao.php");

   $email = htmlentities($_POST["email"]);
   $password = htmlentities($_POST["password"]);

   $returnValue = array();

   if(empty($email) || empty($password)) {
    $returnValue["status"] = "error";
    $returnValue["message"] = "Falta un campo requerido";
    echo json_encode($returnValue);
    return;
   }

   $dao = new MySQLDao();
   $dao->openConnection();
   $userDetails = $dao->getUserDetails($email);

   if(!empty($userDetails)) {
    $returnValue["status"] = "error";
    $returnValue["message"] = "El usuario ya existe";
    echo json_encode($returnValue);
    return;
   }

   $secure_password = md5($password);

   $result = $dao->registerUser($email,$secure_password);

   if($result) {
    $returnValue["status"] = "Success";
    $returnValue["message"] = "Usuario registrado";
    echo json_encode($returnValue);
    return;
   }

   $dao->closeConnection();

   ?>

When I run/debug the app in Xcode, I enter an username and registration into the corresponding fields and in the line 56 where I put a breakpoint:

let task = NSURLSession.sharedSession().dataTaskWithRequest(request) {...

The console throws this error: 2015-11-19 14:02:16.932 userLoginAndRegistration[17265:6170848] NSURLSession/NSURLConnection HTTP load failed (kCFStreamErrorDomainSSL, -9813)

Any help? thanks a lot! If i forgot to add any information please let me know.

Answer 1

I had two errors:

1. The URL of the PHP file should start with 'http' instead of 'https'.
2. I didn't install MySQLi in the VPS server (found here: Fatal error: Class 'MySQLi' not found). After doing that, it worked! Thank you Matt for your advice, it helped me.

Answer 2

You are building your post body with:

let userEmail = userEmailTextField.text
let userPassword = userPasswordTextField.text

let postString = "email=\(userEmail)&password=\(userPassword)"

But userEmail and userPassword are optionals (because text is an optional). You should examine that postString and make sure it is what you intended, because I believe you meant to do:

let userEmail = userEmailTextField.text!
let userPassword = userPasswordTextField.text!

or

let userEmail = userEmailTextField.text ?? ""
let userPassword = userPasswordTextField.text ?? ""

Frankly, you should be percent escaping these, too (e.g. what if the password included a & or other reserved character in it?). For example, in Swift 2:

extension String {

    /// Percent escape value to be added to a HTTP request
    ///
    /// This percent-escapes all characters besize the alphanumeric character set and "-", ".", "_", and "*".
    /// This will also replace spaces with the "+" character as outlined in the application/x-www-form-urlencoded spec:
    ///
    /// http://www.w3.org/TR/html5/forms.html#application/x-www-form-urlencoded-encoding-algorithm
    ///
    /// - returns: Return percent escaped string.

    func stringByAddingPercentEncodingForFormUrlencoded() -> String? {
        let allowedCharacters = NSCharacterSet(charactersInString: "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-._* ")

        return stringByAddingPercentEncodingWithAllowedCharacters(allowedCharacters)?.stringByReplacingOccurrencesOfString(" ", withString: "+")
    }
}

And then:

let userEmail = userEmailTextField.text!.stringByAddingPercentEncodingForFormUrlencoded()
let userPassword = userPasswordTextField.text!.stringByAddingPercentEncodingForFormUrlencoded()

Or, if Swift 3:

extension String {

    /// Percent escape value to be added to a HTTP request
    ///
    /// This percent-escapes all characters besize the alphanumeric character set and "-", ".", "_", and "*".
    /// This will also replace spaces with the "+" character as outlined in the application/x-www-form-urlencoded spec:
    ///
    /// http://www.w3.org/TR/html5/forms.html#application/x-www-form-urlencoded-encoding-algorithm
    ///
    /// - returns: Return percent escaped string.

    func addingPercentEncodingForFormUrlencoded() -> String? {
        let allowedCharacters = CharacterSet(charactersIn: "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-._* ")

        return addingPercentEncoding(withAllowedCharacters: allowedCharacters)?.replacingOccurrences(of: " ", with: "+")
    }
}

And

let userEmail = userEmailTextField.text!.addingPercentEncodingForFormUrlencoded()
let userPassword = userPasswordTextField.text!.addingPercentEncodingForFormUrlencoded()