property
authenticate

authenticate
write-only

Sets the function to be called when a site is requesting authentication. The URL requested and the security realm from the server are passed in the arguments [url] and [realm].

The function returns a [Future] which should complete when the authentication has been resolved. If credentials cannot be provided the [Future] should complete with false. If credentials are available the function should add these using [addCredentials] before completing the [Future] with the value true.

If the [Future] completes with true the request will be retried using the updated credentials. Otherwise response processing will continue normally.