cl-scopes/web/jwt.lisp

40 lines
1.6 KiB
Common Lisp

;;;; cl-scopes/web/jwt - JWT creation and validation
;;;; inspired by: cljwt
(defpackage :scopes/web/jwt
(:use :common-lisp)
(:local-nicknames (:crypt :scopes/util/crypt)
(:util :scopes/util)
(:jzon :com.inuoe.jzon))
(:export #:create #:decode))
(in-package :scopes/web/jwt)
(defvar *header*
(util:to-b64 "{\"alg\":\"HS256\",\"typ\":\"JWT\"}" :scheme :uri))
(defvar *payload-format* "{\"sub\":~s,\"name\":~s,\"exp\":~s}")
(defun create (secret name &key (subject :scopes) (ttl 86400))
(let* ((exp (util:to-unix-time (+ (get-universal-time) ttl)))
(payload (util:to-b64
(format nil *payload-format*
(util:from-keyword subject)
(util:from-keyword name) exp)
:scheme :uri))
(data (str:join "." (list *header* payload)))
(sig (crypt:sign data secret)))
(str:join "." (list data sig))))
(defun decode (token secret)
(let (payload)
(destructuring-bind (data &optional sig) (str:rsplit "." token :limit 2)
(unless sig
(return-from decode (values nil :malformed-token token)))
(unless (equal sig (crypt:sign data secret))
(return-from decode (values nil :invalid-signature (list data sig))))
(destructuring-bind (hjson &optional pjson) (str:split "." data)
(setf payload (jzon:parse (util:from-b64 pjson)))
(when (> (util:to-unix-time (get-universal-time)) (gethash "exp" payload))
(return-from decode (values nil :token-expired payload)))
(values payload nil nil)))))