iPhone Login App using PHP MySQL Tutorial

I needed an easy authentication for my first iPhone app. There didnt seem to be any info on the internet about using PHP/MySQL, so Ive posted this. Im not sure if Apple would even allow it onto the appstore, as I have no plans to submit the app. The code is probably very messy and inefficient as it was my first attempt at Objective-C.

Ill assume you know how to set up a MySQL Database and connect to it using PHP.

Your PHP should look something like:

<?
session_start();
require(“iphoneconnection.php”);
$u = $_GET[‘username’];
$pw = $_GET[‘password’];
$check = “SELECT username, password FROM iphoneusers WHERE username=’$u’ AND password= ‘$pw’”;
$login = mysql_query($check, $connect) or die(mysql_error());
if (mysql_num_rows($login) == 1) {
$row = mysql_fetch_assoc($login);
echo ‘Yes’;exit;
} else {
echo ‘No’;exit;
}
mysql_close($connect);
?>

Where iPhoneconnection.php contains all your database connection info.

Onto the iPhone side.

I reccommend you follow this guide for creating the interface, its better written than my efforts:

http://www.riccomini.name/Topics/Mobile/iPhone/SimpleLoginScreen/

1. Open XCode, create a new project. Use a View Based Application. Ive called mine Login.

grab1

In your LoginViewControler.h put:

#import <UIKit/UIKit.h>
@interface loginViewController : UIViewController {
   IBOutlet UITextField *usernameField;
   IBOutlet UITextField *passwordField;
   IBOutlet UIButton *loginButton;

}
@property (nonatomic, retain) UITextField *usernameField;
@property (nonatomic, retain) UITextField *passwordField;
@property (nonatomic, retain) UIButton *loginButton;
– (IBAction) login: (id) sender;
@end

This initialises the UI elements such as the Username and Login Button which we will be creating in IB in a min.

In your LoginViewController.m put:

#import “loginViewController.h”
@implementation loginViewController
@synthesize usernameField;
@synthesize passwordField;
@synthesize loginButton;
– (IBAction) login: (id) sender
{



   NSString *post =[NSString stringWithFormat:@”username=%@&password=%@”,usernameField.text, passwordField.text];

   NSString *hostStr = @”THIS IS MY URL/iphonelogin-do.php?”;
   hostStr = [hostStr stringByAppendingString:post];
   NSData *dataURL = [NSData dataWithContentsOfURL: [ NSURL URLWithString: hostStr ]];
   NSString *serverOutput = [[NSString alloc] initWithData:dataURL encoding: NSASCIIStringEncoding];






   if([serverOutput isEqualToString:@”Yes”]){


       UIAlertView *alertsuccess = [[UIAlertView alloc] initWithTitle:@”Congrats” message:@”You are authorized “
                                                              delegate:self cancelButtonTitle:@”OK” otherButtonTitles:nil, nil];

       [alertsuccess show];
       [alertsuccess release];


   } else {
       UIAlertView *alertsuccess = [[UIAlertView alloc] initWithTitle:@”Error” message:@”Username or Password Incorrect”
                                                              delegate:self cancelButtonTitle:@”OK” otherButtonTitles:nil, nil];
       [alertsuccess show];
       [alertsuccess release];

   }

}
– (void)didReceiveMemoryWarning {
   // Releases the view if it doesn’t have a superview.
    [super didReceiveMemoryWarning];

   // Release any cached data, images, etc that aren’t in use.
}
– (void)viewDidUnload {
   // Release any retained subviews of the main view.
   // e.g. self.myOutlet = nil;
}
– (void)dealloc {
    [super dealloc];
}
@end

To explain:

This part :

NSString *post =[NSString stringWithFormat:@”username=%@&password=%@”,usernameField.text, passwordField.text];

   NSString *hostStr = @”THIS IS MY URL/iphonelogin-do.php?”;
   hostStr = [hostStr stringByAppendingString:post];
   NSData *dataURL = [NSData dataWithContentsOfURL: [ NSURL URLWithString: hostStr ]];
   NSString *serverOutput = [[NSString alloc] initWithData:dataURL encoding: NSASCIIStringEncoding];

Adds the data entered into the username and password field to the end of the iphonelogin-do.php? as a POST, which is then checked in the PHP. It then returns a “Yes” or “No” which is checked here: