Managing HTTP Cookies on iPhone

NSURLConnection gives you cookie management for free. From the URL Loading System Programming Guide:

The URL loading system automatically sends any stored cookies appropriate for an NSURLRequest. unless the request specifies not to send cookies. Likewise, cookies returned in an NSURLResponse are accepted in accordance with the current cookie acceptance policy.

You can use the NSURLConnection class to perform a HTTP request to login the website, and retrieve the cookie. To perform a request, just create an instance of NSURLConnection and assign a delegate object to it.

NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.google.com/"]];
NSURLConnection *connection = [NSURLConnection connectionWithRequest:request delegate:self];

Then, implement a delegate method.

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
    NSDictionary *fields = [httpResponse allHeaderFields];
    NSString *cookie = [fields valueForKey:@"Set-Cookie"]; // It is your cookie
}

Retain or copy the cookie string. When you want to perform another request, add it to your HTTP header of your NSURLRequest instance.

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://www.google.com/"]];
[request addValue:cookie forHTTPHeaderField:@"Cookie"];