From 41c341624c16607ac710aac446cc0ead3c53671b Mon Sep 17 00:00:00 2001
From: arno <arenevier@fdn.fr>
Date: Fri, 7 Aug 2009 23:49:54 +0200
Subject: [PATCH] implements ETag caching for items.php and news.php

---
 items.php | 21 ++++++++++++++++++---
 news.php  | 19 +++++++++++++++++--
 2 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/items.php b/items.php
index c363183..e7a9723 100644
--- a/items.php
+++ b/items.php
@@ -6,9 +6,22 @@ require_once ("./inc/settings.php");
 require_once ("./inc/utils.php");
 require_once ("./inc/db/mysql.php");
 
-function main ($features) {
+function headers_callback ($output) {
+    $etag = md5 ($output);
+    if ((isset ($_SERVER ["HTTP_IF_NONE_MATCH"])) && 
+         ($_SERVER ["HTTP_IF_NONE_MATCH"] == $etag)) {
+         header ("HTTP/1.1 304 Not Modified");
+         exit ();
+    }
 
-    header ("Cache-control: no-cache");
+    header ("Content-type: application/vnd.google-earth.kml+xml");
+    header ("Cache-control: must-revalidate");
+    header (sprintf ("ETag: %s", $etag));
+
+    return $output;
+}
+
+function main ($features) {
 
     echo '<?xml version="1.0" encoding="UTF-8"?>
 <kml xmlns="http://www.opengis.net/kml/2.2">
@@ -70,6 +83,8 @@ try {
 } catch (Exception $e) {
     exit ("server error");
 }
-header ("Content-type: application/vnd.google-earth.kml+xml");
+
+ob_start ("headers_callback");
 main ($features);
+ob_end_flush ()
 ?>
diff --git a/news.php b/news.php
index b729bb7..6eb78e6 100644
--- a/news.php
+++ b/news.php
@@ -6,8 +6,20 @@ require_once ("./inc/settings.php");
 require_once ("./inc/db/mysql.php");
 require_once ("./inc/utils.php");
 
-header ("Content-type: application/atom+xml; charset=UTF-8");
-header("Cache-control: no-cache");
+function headers_callback ($output) {
+    $etag = md5 ($output);
+    if ((isset ($_SERVER ["HTTP_IF_NONE_MATCH"])) && 
+         ($_SERVER ["HTTP_IF_NONE_MATCH"] == $etag)) {
+         header ("HTTP/1.1 304 Not Modified");
+         exit ();
+    }
+
+    header ("Content-type: application/atom+xml; charset=UTF-8");
+    header ("Cache-control: must-revalidate");
+    header (sprintf ("ETag: %s", $etag));
+
+    return $output;
+}
 
 function date3339 ($feature) {
     $date = date ('Y-m-d\TH:i:s', $feature->date);
@@ -118,5 +130,8 @@ try {
 } catch (Exception $e) {
     exit ("server error");
 }
+
+ob_start ("headers_callback");
 main ($features);
+ob_end_flush ()
 ?>
-- 
2.39.2