From 0161b4b655e549d57fef122cabae5d4e380a4e95 Mon Sep 17 00:00:00 2001
From: Matthias Benkard <code@mail.matthias.benkard.de>
Date: Wed, 7 Oct 2009 12:16:35 +0200
Subject: Implement sane caching behaviour.

Ignore-this: 8ed0815613cb44c0eee9d8ac47e1753b

darcs-hash:e41ff965d8172b7979369cb0df98302f29a9a9c4
---
 globals.lisp     |  4 ++++
 journal.lisp     |  2 ++
 main.lisp        |  2 ++
 mulk-journal.asd |  2 +-
 utils.lisp       | 10 ++++++++++
 5 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/globals.lisp b/globals.lisp
index a609e63..1637931 100644
--- a/globals.lisp
+++ b/globals.lisp
@@ -76,3 +76,7 @@
   "Warnings that should be displayed to the user.")
 
 (defparameter *full-entry-view* t)
+
+(defparameter *site-root* nil)
+(defparameter *if-modified-since* nil)
+
diff --git a/journal.lisp b/journal.lisp
index cfac6fd..f1fd5b1 100755
--- a/journal.lisp
+++ b/journal.lisp
@@ -346,6 +346,7 @@
   ;;
   ;; (http-add-header "Last-Modified" (http-timestamp (compute-journal-last-modified-date)))
   (http-add-header "Content-Language" "de")
+  (http-add-header "Cache-Control" "public")
   (http-send-headers "text/html; charset=UTF-8")
 
   (<xhtml :xmlns "http://www.w3.org/1999/xhtml"
@@ -409,6 +410,7 @@
 
 (defun show-web-journal ()
   #.(locally-enable-sql-reader-syntax)
+  (revalidate-cache-or-die)
   (with-web-journal ((if (member *action* '(:view :edit :preview :post-comment
                                             :save-entry))
                          (title-of (find-entry *post-number*))
diff --git a/main.lisp b/main.lisp
index ae2c0cb..c8b489e 100644
--- a/main.lisp
+++ b/main.lisp
@@ -54,6 +54,8 @@
                                       (*post-number*                      :view)
                                       (t                                  nil))))
          (*method*          (keywordify (gethash "REQUEST_METHOD" *http-env*)))
+         (*if-modified-since* #+clisp (ext:getenv "HTTP_IF_MODIFIED_SINCE")
+                              #-clisp nil)
          (*script-filename* (pathname-as-file
                              (or (gethash "SCRIPT_FILENAME" *http-env*)
                                  "/home/mulk/Dokumente/Projekte/Mulkblog/journal.cgi")))
diff --git a/mulk-journal.asd b/mulk-journal.asd
index 6cd1da5..49a1e12 100644
--- a/mulk-journal.asd
+++ b/mulk-journal.asd
@@ -26,7 +26,7 @@
   :depends-on  (#:cl-ppcre #:cl-fad #:iterate #:cl-markdown #:parenscript
                 #:yaclml #:lisp-cgi-utils #:alexandria #:xml-emitter
                 #:split-sequence #:clsql #:clsql-uffi #:clsql-sqlite3
-                #:drakma)
+                #:drakma #:cybertiggyr-time)
   :components  ((:file "defpackage")
                 (:file "macros")
                 (:file "globals")
diff --git a/utils.lisp b/utils.lisp
index 74030b8..590d310 100644
--- a/utils.lisp
+++ b/utils.lisp
@@ -325,3 +325,13 @@ ELEMENT-TYPE as the stream's."
                 (submitter-user-agent comment)
                 (spamp comment)
                 (body-of comment))))
+
+(defun revalidate-cache-or-die ()
+  #+clisp
+    (let ((time (cybertiggyr-time:parse-time *if-modified-since*)))
+      (when (and (integerp time) (>= *if-modified-since* (compute-journal-last-modified-date)))
+        (http-add-header "Status: 304 Not Modified")
+        (http-send-headers)
+        (ext:quit 0)))
+  #-clisp
+    nil)
-- 
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