The realm used for authentication purposes.
A partial function mapping (realm, user) to the appropriate password.
Check if req contains valid credentials.
Check if req contains valid credentials. You may assume that the returned Task is executed at most once (to allow for side-effects, e.g. the incrementation of a nonce counter in DigestAuthentication).
The request received from the client.
If req contains valid credentials, a copy of req is returned that contains additional attributes pertaining to authentication such as the username and realm from the valid credentials. If req does not contain valid credentials, a challenge is returned. This challenge will be included in the HTTP 401 Unauthorized response that is returned to the client.
Provides Basic Authentication from RFC 2617.