Redirect URL from NSURLConnection - ios

Question

I am trying to solve the following problem:
I am sending a POST request with some additional header values to a specific URL. For that purpose I use NSMutabeURLRequest. It works nice when i NSLog the response, but I also need the URL of the redirect. If I use something like request.URL in the competitionHandler it returns the URL i sent my POST request to, it's not what I need.
Any tips on how to get the URL of the redirect? (It would be nice if it won't change my code significantly.
Below is what I have so far:
url = [NSURL URLWithString:#"https://***"];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
[request setHTTPMethod:#"POST"];
[request setValue:#"application/json; charset=utf-8" forHTTPHeaderField:#"Content-Type"];
//Some additional values are set here
[request setHTTPBody:data];
NSOperationQueue *queue = [[NSOperationQueue alloc] init];
[NSURLConnection sendAsynchronousRequest:request queue:queue completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
NSLog(#"%#", response);
if (error)
NSLog(#"%s: NSURLConnection error: %#", __FUNCTION__, error);
NSString *responseString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSLog(#"responseString: %#",responseString);
}];

Answer 1

From Apple's Developer Docs:
A redirect occurs when a server responds to a request by indicating that the client should make a new request to a different URL. The NSURLSession, NSURLConnection, and NSURLDownload classes notify their delegates when this occurs.
To handle a redirect, your URL loading class delegate must implement one of the following delegate methods:
For NSURLSession, implement the URLSession:task:willPerformHTTPRedirection:newRequest:completionHandler: delegate method.
For NSURLConnection, implement the connection:willSendRequest:redirectResponse: delegate method.
For NSURLDownload, implement the download:willSendRequest:redirectResponse: delegate method.
In these methods, the delegate can examine the new request and the response that caused the redirect, and can return a new request object through the completion handler for NSURLSession or through the return value for NSURLConnection and NSURLDownload.
The delegate can do any of the following:
Allow the redirect by simply returning the provided request.
Create a new request, pointing to a different URL, and return that request.
Reject the redirect and receive any existing data from the connection by returning nil.
In addition, the delegate can cancel both the redirect and the connection. With NSURLSession, the delegate does this by sending the cancel message to the task object. With the NSURLConnection or NSURLDownload APIs, the delegate does this by sending the cancel message to the NSURLConnection or NSURLDownload object.
The delegate also receives the connection:willSendRequest:redirectResponse: message if the NSURLProtocol subclass that handles the request has changed the NSURLRequest in order to standardize its format, for example, changing a request for http://www.apple.com to http://www.apple.com/. This occurs because the standardized, or canonical, version of the request is used for cache management. In this special case, the response passed to the delegate is nil and the delegate should simply return the provided request.
So basically, you need to make use of the connection:willSendRequest:redirectResponse: delegate method to grab the new url and perform whatever operation you need to on it

Answer 2

The problem is that you're using the sendAsynchronousRequest:queue:completionHandler: method, which uses a completion handler and doesn't take a delegate.
After you implement the delegate method, you'll need to use NSURLConnection's initWithRequest:delegate: or initWithRequest:delegate:startImmediately: method to create the NSURLConnection object instead. You'll also have to implement a delegate method to obtain the data returned by the request.
Alternatively, if you don't have to support anything older than iOS 7 or OS X v10.9, NSURLSession provides the ability to use delegate methods for handling redirection even in combination with methods that take a completion callback.