From b4cd3bb5cba1551ee85b66716deb2f26722b1ef8 Mon Sep 17 00:00:00 2001 From: colin Date: Wed, 25 Jan 2023 18:26:18 -0800 Subject: Add: initial flash function; modified endpoints to use it This is untested. Just commiting to share. --- flash.lisp | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 flash.lisp (limited to 'flash.lisp') diff --git a/flash.lisp b/flash.lisp new file mode 100644 index 0000000..27a6c31 --- /dev/null +++ b/flash.lisp @@ -0,0 +1,41 @@ +;;;; flash.lisp -- communicating between page loads + +(in-package :dnd) + +(defvar *flashes* + (make-hash-table :test #'equal :synchronized t)) + +(defparameter +flash-cookie-name+ "DNDFLASHKEY") +(defparameter +flash-value-lifetime+ 10 + "Number of seconds a flashed value lives.") + + +(defun flash (value) + "A flash is a one-time inter-request value. Once stored, it can only +be retrieved once. And if not retrieved in a short period of time, it +expires." + (let ((key (nuid)) + (now (get-universal-time))) + (setf (gethash key *flashes*) (cons value now)) + (lzb:set-response-cookie + +flash-cookie-name+ key + ;; TODO: generalize domain + :path "/" :domain "localhost" + :expires (+ +flash-value-lifetime+ now)) + key)) + +(defun flashed-value-alive-p (val) + (<= (+ (cdr val) +flash-value-lifetime+) + (get-universal-time))) + +(defun flashed-value () + "Retrieves the value flashed in this request, if it exists, and +returns it. + +Removes the flashed value from the hash table if it was found." + (a:when-let* ((key (lzb:request-cookie +flash-cookie-name+)) + (val (gethash key *flashes*))) + (remhash key *flashes*) + (when (flashed-value-alive-p val) + (car val)))) + -- cgit v1.2.3