From b4cd3bb5cba1551ee85b66716deb2f26722b1ef8 Mon Sep 17 00:00:00 2001
From: colin <colin@cicadas.surf>
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.
---
 endpoints.lisp | 13 ++++++++-----
 flash.lisp     | 41 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 5 deletions(-)
 create mode 100644 flash.lisp

diff --git a/endpoints.lisp b/endpoints.lisp
index e947562..ff6f97c 100644
--- a/endpoints.lisp
+++ b/endpoints.lisp
@@ -38,18 +38,21 @@ I.e. It should be called within the scope of a request handler."
 (defendpoint* :get "/" () ()
   (redirect-to "/tavern-door"))
 
-(defendpoint* :get "/tavern-door" ((name str)) ()
-  (if name (doorkeeper :message (format nil "M'fraid I've n'er 'eard o' ~a." name))
-      (doorkeeper)))
+(defendpoint* :get "/tavern-door" () ()
+  (a:if-let (name (flashed-value))
+    (doorkeeper :message (format nil "M'fraid I've n'er 'eard o' ~a." name))
+    (doorkeeper)))
 
 (defendpoint* :post "/tavern-door" () ()
   (with-plist ((name :name)) (lzb:request-body)
     (a:if-let ((hero (hero-known-as name)))
       (a:when-let ((sesh (new-sesh hero)))
 	(lzb:set-response-cookie +session-cookie-name+ (session-id sesh)
-				 :path "/" :domain "localhost")
+				 :path "/" :domain "localhost")  ; TODO: generalize domain
 	(redirect-to "/tavern"))
-      (redirect-to (format nil "/tavern-door?name=~a" (quri:url-encode name))))))
+      (progn
+        (flash name)
+        (redirect-to (format nil "/tavern-door"))))))
 
 (defendpoint* :get "/godess-shrine" () ()
   (godess-shrine))
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