The magic hash that makes http basic logout work with nsurlconnection

// 2008 by Johannes Fahrenkrug, http://blog.springenwerk.com

@implementation AccountViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
	if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
		// Initialization code
		self.title = @"Settings";
		// NSMutableData * declared in .h
		receivedData = [[NSMutableData data] retain];
	}
	return self;
}

- (IBAction)login:(id)sender {	
	//display an alert if either username or pwd are empty
	if ([[usernameTextField text] length] < 1 || [[passwordTextField text] length] < 1) {
		UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Login" message:@"Neither the username nor password may be empty!" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
		[alert show];
		[alert release];
		return;
	}
	
	// reset the credentials cache...		
	NSDictionary *credentialsDict = [[NSURLCredentialStorage sharedCredentialStorage] allCredentials];
	
	if ([credentialsDict count] > 0) {
		// the credentialsDict has NSURLProtectionSpace objs as keys and dicts of userName => NSURLCredential
		NSEnumerator *protectionSpaceEnumerator = [credentialsDict keyEnumerator];
		id urlProtectionSpace;
		
		// iterate over all NSURLProtectionSpaces
		while (urlProtectionSpace = [protectionSpaceEnumerator nextObject]) {
			NSEnumerator *userNameEnumerator = [[credentialsDict objectForKey:urlProtectionSpace] keyEnumerator];
			id userName;
			
			// iterate over all usernames for this protectionspace, which are the keys for the actual NSURLCredentials
			while (userName = [userNameEnumerator nextObject]) {
				NSURLCredential *cred = [[credentialsDict objectForKey:urlProtectionSpace] objectForKey:userName];
				NSLog(@"cred to be removed: %@", cred);
				[[NSURLCredentialStorage sharedCredentialStorage] removeCredential:cred forProtectionSpace:urlProtectionSpace];
			}
		}
	}
	
    // Note the magic hash that makes it all work! -------------------------------------------------------------------------------V
	NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://localhost:3000/something.json#"] cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:20];
		
	NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
	
	if (!theConnection) {
		UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Network Error" message:@"Could not login!" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
		[alert show];
		[alert release];
		return;
	}

}


#pragma mark urlconnection delegate methods
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
	// this method is called when the server has determined that it
	// has enough information to create the NSURLResponse
	
	// it can be called multiple times, for example in the case of a
	// redirect, so each time we reset the data.
	// receivedData is declared as a method instance elsewhere
	[receivedData setLength:0];
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
	// append the new data to the receivedData
	// receivedData is declared as a method instance elsewhere
	[receivedData appendData:data];
}

- (void)connection:(NSURLConnection *)connection
  didFailWithError:(NSError *)error
{
	[connection release];
		
	// inform the user
	UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Login Error" message:[NSString stringWithFormat:@"The connection failed with this error: %@", [error localizedDescription]] delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
	[alert show];
	[alert release];
	
	NSLog(@"Connection failed! Error - %@ %@",
		  [error localizedDescription],
		  [[error userInfo] objectForKey:NSErrorFailingURLStringKey]);
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
	NSLog(@"login succeeded!");

	[connection release];
		
	NSString *response = [NSString stringWithCString:[receivedData bytes] length:[receivedData length]];	

	NSLog(response);
}

- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge {
	NSLog(@"got auth challange");

	if ([challenge previousFailureCount] == 0) {
		[[challenge sender]  useCredential:[NSURLCredential credentialWithUser:[usernameTextField text] password:[passwordTextField text] persistence:NSURLCredentialPersistenceForSession] forAuthenticationChallenge:challenge];
	} else {
        [[challenge sender] cancelAuthenticationChallenge:challenge];        
    }
}

- (void)dealloc {
	[receivedData release];
	[super dealloc];
}



@end