Tells the delegate that the connection will send a request for an authentication challenge.
- iOS 5.0+
- macOS 10.7+
- UIKit for Mac 13.0+Beta
- tvOS 9.0+
- watchOS 2.0+
The connection sending the message.
The authentication challenge for which a request is being sent.
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(_:. In fact, those other methods are not invoked (except on older operating systems, where applicable).
In this method,you must invoke one of the challenge-responder methods (
You might also want to analyze
challenge for the authentication scheme and the proposed credential before calling a
URLAuthentication method. You should never assume that a proposed credential is present. You can either create your own credential and respond with that, or you can send the proposed credential back. (Because this object is immutable, if you want to change it you must copy it and then modify the copy.)