RestKit requests hang on HTTP errors - ios

Question

I am trying to make my app handle HTTP client errors. Ideally, I would like to run a static method whenever such an error occurs, regardless of the request that caused it.
It seems that I am doing something wrong -- I have tried to add a RKDynamicResponseDescriptor to call the method, but it doesn't get called. Whenever my server responds with an error, the request never finishes (the network activity indicator keeps spinning and the AFNetworkingOperationDidFinishNotification is never posted.)
I can reproduce the behavior by creating a new AFHTTPRequest request like this:
request = [[RKObjectManager sharedManager].HTTPClient requestWithMethod:#"GET" path:#"events" parameters:nil];
AFHTTPRequestOperation *operation = [AFJSONRequestOperation JSONRequestOperationWithRequest:request
success:^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {
NSLog(#"%#", JSON);
}
failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error, id JSON) {
NSLog(#"Request Failed with Error: %#, %#", error, error.userInfo);
}];
Neither the success nor the failure block is called. If I replace the first line with
request = [[NSURLRequest alloc] initWithURL:[NSURL URLWithString:url]];
the blocks get called. How can I make RestKit handle the HTTP error response?
Edit 1: Apparently this happens in both cases when the server returns 401 with an authentication challenge. I have tried setting a breakpoint in RKHTTPRequestOperation in didReceiveAuthenticationChallenge, but it is not triggered. My Fiddler shows that only one request is sent.

Answer 1

After lots of fiddling, I think I have found the reason for this problem. The AFUrlConnectionRequest class implements the connection:willSendRequestForAuthenticationChallenge:delegate method when SSL pinning is enabled. The implementation simply returns if the authentication challenge is not related to SSL.
From the documentation of NSUrlConnectionDelegate:
This method allows the delegate to make an informed decision about connection authentication at once. If the delegate implements this method, it has no need to implement
connection:canAuthenticateAgainstProtectionSpace:,
connection:didReceiveAuthenticationChallenge:,
connectionShouldUseCredentialStorage:.
In fact, these other methods are not invoked.
The methods will not be invoked, and thus RestKit never knows that the request resulted in HTTP error 401.
I solved the problem by removing this define, so the delegate method is not implemented:
#define _AFNETWORKING_PIN_SSL_CERTIFICATES_