Radiance Authenticate Draft

(defmethod authenticate ((verify verify) &key &allow-other-keys)
  (let ((token (hunchentoot:cookie-in "token" (request *radiance-request*))))
    (if token
        (progn
          (setf token (decrypt token (config-tree :verify :session :secret)))
          (if (and token (find #\- token))
              (let* ((username (subseq token 0 (position #\- token)))
                     (session (session-start (implementation 'session) username))
                     (user (session-user session))
                     (token (subseq token (1+ (position #\- token)))))
                (if (user-saved-p user)
                    (authenticate-user user session token)
                    (error "Unknown user: ~a" username)))
              (error "Malformed token: ~a" token)))
        (error "No token received."))))

(defun authenticate-user (user session token)
  (setf token (if (config-tree :verify :session :use-per-user-secret)
                  (decrypt token (user-field user "secret"))
                  token))
  (let ((data (split-sequence:split-sequence #\: token)))
    (if (= (length data) 3)
        (destructuring-bind (timestamp random session-id) data
          (declare (ignore random))
          (if (string= session-id (uuid session))
              (progn (log:info "User ~a successfully authenticated session ~a (initiated on ~a)" user session-id timestamp)
                     session)
              (error "Invalid session ID: ~a" session-id)))
        (error "Invalid data length: ~a" (length data)))))