This hook is called from the =/pengine/create= HTTP handler to
discover whether the server is accessed by an authorized user. It
can react in three ways:
Succeed, binding User to a ground term. The authentity of the
user is available through pengine_user/1.
Fail. The =/create= succeeds, but the pengine is not associated
with a user.
Throw an exception to prevent creation of the pengine. Two
meaningful exceptions are:
throw(http_reply(authorise(basic(Realm))))
Start a normal HTTP login challenge (reply 401)
throw(http_reply(forbidden(Path))))
Reject the request using a 403 repply.
See also
- http_authenticate/3 can be used to implement this hook using
default HTTP authentication data.