NSURLConnection - Disable the authentication challenge response mechanism - ios

Question

SITUATION
Using AFNetworking (NSURLConnection) to access my server API
The API needs Basic Authentication with token as username
The API returns HTTP 401 when token is invalid
I set the Basic Authentication headers before any request
If it returns 401, I retry like this:
AFHTTPRequestOperation *requestOperation = [MyHTTPClient.sharedClient HTTPRequestOperationWithRequest:request success:^(AFHTTPRequestOperation *operation, id responseObject) {
processSuccessBlock(operation, responseObject);
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
processFailureBlock(operation, error);
if (operation.response.statusCode == 401)
[MyHTTPClient.sharedClient refreshTokenAndRetryOperation:operation success:processSuccessBlock failure:processFailureBlock];
}];
PROBLEM
When the server returns HTTP 401 with a Basic Authentication challenge, AFNetworking/NSURLConnection sends the identical request twice (initial request and then in answer to the authentication challenge)
But because of the code above that I handle the HTTP 401 myself, this is totally unnecessary and I want it to stop answering the authentication challenge automatically
WHAT I'VE TRIED
Responding with cancelAuthenticationChallenge: to willSendRequestForAuthenticationChallenge: is aborting the second call, but it gives the error code -1012 (NSURLErrorUserCancelledAuthentication) instead of 401 and masks the real response
How do you disable the authentication challenge response mechanism so you get the servers response without calling it twice?

Answer 1

You have a few of options to fully customize the authentication handling:
Utilize setWillSendRequestForAuthenticationChallengeBlock: and setAuthenticationAgainstProtectionSpaceBlock: from class AFURLConnectionOperation and set corresponding blocks where you can tailor the mechanism you require.
The headers contain documentation.
Override connection:willSendRequestForAuthenticationChallenge: in a subclass of AFURLConnectionOperation. This will effectively override the complete authentication mechanism setup in AFNetworking.
Note, that you cannot disable the "server validates client identity" authentication challenge -- this is part of the server. You MUST provide the correct credentials for the requested authentication method.

Answer 2

Try this.
- (void)connection:(NSURLConnection *)connection willSendRequestForAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
{
SecTrustRef trust = challenge.protectionSpace.serverTrust;
NSURLCredential *cred;
cred = [NSURLCredential credentialForTrust:trust];
[challenge.sender useCredential:cred forAuthenticationChallenge:challenge];
}