iOS - How to create a login process using keychain / Core Data?

Question

I am creating a multi-user iPhone app, and I am trying to finish up the coding for the user login in process. I can successfully create an account, and store the data the user inputs into the Core Data DB, and the pin (password) into the Keychain, so now I am trying to complete the login process. The following code listed below is what I have so far, and I am wondering what I need to do to complete the login process.

- (IBAction)processLogin:(id)sender {

// hide keyboard
[_textFieldUsername resignFirstResponder];
[_textFieldPin resignFirstResponder];


// First - make activity indicator visible, then start animating, then turn of wrong user / pin label
_welcomeActivityIndicator.hidden = FALSE;
[_welcomeActivityIndicator startAnimating];
[_wrongUserPin setHidden:YES];

// check if username and pin text fields are populated
if ([_textFieldUsername.text length ] == 0 &&  [_textFieldPin.text length ] == 0)
{
    [_welcomeActivityIndicator stopAnimating];
    [_wrongUserPin setHidden:NO];   
}

// CORE DATA    
NSFetchRequest *request= [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Account" inManagedObjectContext:_managedObjectContext];
NSPredicate *predicate =[NSPredicate predicateWithFormat:@"username=%@",self.textFieldUsername.text];

//check pin
Account *pinAccount = [[Account alloc] init];
[pinAccount.password isEqualToString:_textFieldPin.text];

[request setEntity:entity];
[request setPredicate:predicate];

NSError *error = nil;

NSArray *array = [_managedObjectContext executeFetchRequest:request error:&error];
if (array != nil) {
    NSUInteger count = [array count]; // may be 0 if the object has been deleted.
    NSLog(@"Username may exist, %@",count);
}

else {
    NSLog(@"Username does not exist.");
}

// TODO - put this in proper place - play audio bell if user logs in correctly
CFBundleRef mainBundle = CFBundleGetMainBundle();
CFURLRef soundFileURLRef;
soundFileURLRef = CFBundleCopyResourceURL(mainBundle, (CFStringRef) @"Glass", CFSTR("aiff"), NULL);
UInt32 soundID;
AudioServicesCreateSystemSoundID(soundFileURLRef, &soundID);
AudioServicesPlaySystemSound(soundID);

// TODO - put this in proper place - Load ViewControllerHome
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
ViewControllerHome *home = (ViewControllerHome *)[storyboard instantiateViewControllerWithIdentifier:@"Home"];
[self presentModalViewController:home animated:YES];

}

The Account and AccountBase class files m and h look like the following:

Account.h http://pastie.org/4149299

Account.m http://pastie.org/4149296

AccountBase.h http://pastie.org/4149301

AccountBase.m http://pastie.org/4149302

I would appreciate any ideas or thoughts, and thanks for reading.

Answer 1

I was able to complete the login process with the following code.

- (IBAction)processLogin:(id)sender {

// hide keyboard
[_textFieldUsername resignFirstResponder];
[_textFieldPin resignFirstResponder];


// First - make activity indicator visible, then start animating, then turn of wrong user / pin label
_welcomeActivityIndicator.hidden = FALSE;
[_welcomeActivityIndicator startAnimating];
[_wrongUserPin setHidden:YES];

// check if username and pin text fields are populated
if ([_textFieldUsername.text length ] == 0 &&  [_textFieldPin.text length ] == 0)
{
    [_welcomeActivityIndicator stopAnimating];
    [_wrongUserPin setHidden:NO];   
}

// CORE DATA
NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Account" inManagedObjectContext:_managedObjectContext];

// set entity for request
[request setEntity:entity];

// filter results using a predicate
NSPredicate *pred =[NSPredicate predicateWithFormat:(@"username = %@"), _textFieldUsername.text];

// set predicate for the request
[request setPredicate:pred];

NSError *error = nil;

// store DB usernames in results array
NSArray *results = [_managedObjectContext executeFetchRequest:request error:&error];

NSLog(@"The returned results are %@",results);


// check text field against results stored in DB
for (Account *anAccount in results) {
    if ([anAccount.username isEqualToString:_textFieldUsername.text]){
        NSLog(@"Your username exists");
        if ([anAccount.password isEqualToString:_textFieldPin.text]){
            NSLog(@"Your pin is correct");

            // TODO - put this in proper place - play audio bell if user logs in correctly
            CFBundleRef mainBundle = CFBundleGetMainBundle();
            CFURLRef soundFileURLRef;
            soundFileURLRef = CFBundleCopyResourceURL(mainBundle, (CFStringRef) @"Glass", CFSTR("aiff"), NULL);
            UInt32 soundID;
            AudioServicesCreateSystemSoundID(soundFileURLRef, &soundID);
            AudioServicesPlaySystemSound(soundID);

            // TODO - put this in proper place - Load ViewController(Root)Home
            if([anAccount.username isEqualToString:@"root"])
            {
                UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
                ViewControllerRootHome *roothome = (ViewControllerRootHome *)[storyboard instantiateViewControllerWithIdentifier:@"rootHome"];
                [self presentModalViewController:roothome animated:YES];
            }
            else {
                UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
                ViewControllerHome *home = (ViewControllerHome *)[storyboard instantiateViewControllerWithIdentifier:@"Home"];
                [self presentModalViewController:home animated:YES];
            }
        }
        else {
            NSLog(@"Your pin is wrong");
            [_welcomeActivityIndicator stopAnimating];
            [_wrongUserPin setHidden:NO];
            }
        }
    else {
        NSLog(@"Your username was not found");
        [_welcomeActivityIndicator stopAnimating];
        [_wrongUserPin setHidden:NO];
        }
    }

}