[geeklog-cvs] geeklog: Implemented Conditional GET (somewhat experimental)

[geeklog-cvs at lists.geeklog.net]

details:   http://project.geeklog.net/cgi-bin/hgweb.cgi/rev/aeced27e1da9
changeset: 6409:aeced27e1da9
user:      Dirk Haun <dirk at haun-online.de>
date:      Fri Oct 03 11:34:33 2008 +0200
description:
Implemented Conditional GET (somewhat experimental)

diffstat:

1 file changed, 47 insertions(+), 19 deletions(-)
public_html/getimage.php |   66 ++++++++++++++++++++++++++++++++--------------

diffs (120 lines):

diff -r 12a47f2285a6 -r aeced27e1da9 public_html/getimage.php
--- a/public_html/getimage.php	Fri Oct 03 10:48:53 2008 +0200
+++ b/public_html/getimage.php	Fri Oct 03 11:34:33 2008 +0200
@@ -2,15 +2,16 @@
 
 /* Reminder: always indent with 4 spaces (no tabs). */
 // +---------------------------------------------------------------------------+
-// | Geeklog 1.4                                                               |
+// | Geeklog 1.5                                                               |
 // +---------------------------------------------------------------------------+
 // | getimage.php                                                              |
 // |                                                                           |
 // | Shows images outside of the webtree                                       |
 // +---------------------------------------------------------------------------+
-// | Copyright (C) 2004-2006 by the following authors:                         |
+// | Copyright (C) 2004-2008 by the following authors:                         |
 // |                                                                           |
 // | Authors: Tony Bibbs        - tony AT tonybibbs DOT com                    |
+// |          Dirk Haun         - dirk AT haun-online DOT de                   |
 // +---------------------------------------------------------------------------+
 // |                                                                           |
 // | This program is free software; you can redistribute it and/or             |
@@ -36,12 +37,11 @@
 * serve the images from outside of the webtree to a place that the webserver
 * user can actually write too
 *
-* @author   Tony Bibbs <tony at tonybibbs.com>
+* @author   Tony Bibbs <tony AT tonybibbs DOT com>
 *
 */
 
 require_once 'lib-common.php';
-
 require_once $_CONF['path_system'] . 'classes/downloader.class.php';
 
 $downloader = new downloader();
@@ -50,21 +50,18 @@
 
 $downloader->setLogging(true);
 
-$downloader->setAllowedExtensions(array('gif' => 'image/gif',
-                                        'jpg' => 'image/jpeg',
+$downloader->setAllowedExtensions(array('gif'  => 'image/gif',
+                                        'jpg'  => 'image/jpeg',
                                         'jpeg' => 'image/jpeg',
-                                        'png' => 'image/x-png',
+                                        'png'  => 'image/png',
+                                        'png'  => 'image/x-png'
                                        )
                                  );
                                  
-$mode = '';
-if (isset($_GET['mode'])) {
-    $mode = $_GET['mode'];
-}
-$image = '';
-if (isset($_GET['image'])) {
-    $image = COM_applyFilter ($_GET['image']);
-}
+COM_setArgNames(array('mode', 'image'));
+$mode  = COM_applyFilter(COM_getArgument('mode'));
+$image = COM_applyFilter(COM_getArgument('image'));
+
 if (strstr($image, '..')) {
     // Can you believe this, some jackass tried to relative pathing to access
     // files they shouldn't have access to?
@@ -90,7 +87,36 @@
 }
 
 // Let's see if we don't have a legit file.  If not bail
-if (is_file($downloader->getPath() . $image)) {
+$pathToImage = $downloader->getPath() . $image;
+if (is_file($pathToImage)) {
+
+    // support conditional GET, if possible
+    $st = @stat($pathToImage);
+    if (is_array($st)) {
+        // cf. RFC 2616, Section 3.3.1 Full Date
+        $last_mod = str_replace('+0000', 'GMT', gmdate('r', $st['mtime']));
+        $etag     = '"' . md5($image) . '"';
+
+        $mod_since  = '';
+        $none_match = '';
+        if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
+            $mod_since = $_SERVER['HTTP_IF_MODIFIED_SINCE'];
+        }
+        if (isset($_SERVER['HTTP_IF_NONE_MATCH'])) {
+            $none_match = $_SERVER['HTTP_IF_NONE_MATCH'];
+        }
+
+        if (($last_mod == $mod_since) && ($etag == $none_match)) {
+            // image hasn't change - we're done
+            header('HTTP/1.1 304 Not Modified');
+            header('Status: 304 Not Modified');
+            exit;
+        }
+
+        header('Last-Modified: ' . $last_mod);
+        header('ETag: ' . $etag);
+    }
+
     if ($mode == 'show') {
         echo '<html><body><img src="' . $_CONF['site_url'] . '/getimage.php?mode=articles&image=' . $image . '" alt=""' . XHTML . '></body></html>';
     } else {
@@ -99,10 +125,12 @@
 } else {
     $display = COM_errorLog('File, ' . $image . ', was not found in getimage.php');
 
+    // send 404 in any case
+    header('HTTP/1.1 404 Not Found');
+    header('Status: 404 Not Found');
+
     if ($mode == 'show') {
-        echo COM_siteHeader ('menu') . $display . COM_siteFooter ();
-    } else {
-        header ('HTTP/1.0 404 Not Found');
+        echo COM_siteHeader('menu') . $display . COM_siteFooter();
     }
 }