gistfile1.lisp

(ql:quickload :ironclad)
(ql:quickload :flexi-streams)

(defgeneric authenticate (user secret)
  (:documentation "Authentication user with secret. Secret may be a
  password or a token."))

(defclass user ()
  ((email :initarg :email :accessor email)
   (password :initarg :password)
   (salt :initarg :salt :initform (ironclad:make-random-salt) :reader salt)))


(defun new-user (email password)
  (make-instance 'user
                 :email email
                 :password password))

(defmethod initialize-instance :after ((user user) &rest initargs)
  (declare (ignore initargs))
  (with-slots (password) user
    (setf password
          (ironclad:pbkdf2-hash-password-to-combined-string (flexi-streams:string-to-octets password)))))

(defmethod (setf password) (new-value (user user))
  (with-slots (password) user
    (setf password (ironclad:pbkdf2-hash-password-to-combined-string (flexi-streams:string-to-octets new-value)))))

(defmethod password ((user user))
  (slot-value user 'password))

(defmethod authenticate ((user user) password)
  (ironclad:pbkdf2-check-password (flexi-streams:string-to-octets password) (password user)))

;; Example
(defvar *user* (new-user "foo" "ohhai"))
(authenticate *user* "ohhai") ; => t
(setf (password *user*) "hai")
(authenticate *user "ohhai") ; => nil
(authenticate *user "hai") ; => t