From 1cb1157809878bbfddf061d676ecc41fea17cfd7 Mon Sep 17 00:00:00 2001
From: Matteo Scaramuccia <moodle@matteoscaramuccia.com>
Date: Mon, 3 Jun 2013 21:41:21 +0200
Subject: [PATCH 1/2] MDL-39832 Files: Revert MDL-39688 commit,
 6ce0c9ce42fa7849e67d7611a628ece51c336c5f

MDL-39688 has been successful in providing a solution for the issue but further
investigations done in MDL-39832 have got the evidence that the given solution
is more likely a workaround.
---
 lib/filelib.php      | 10 +---------
 lib/xsendfilelib.php |  6 ------
 2 files changed, 1 insertion(+), 15 deletions(-)

diff --git a/lib/filelib.php b/lib/filelib.php
index 2d9b2b393cb..1820beac83c 100644
--- a/lib/filelib.php
+++ b/lib/filelib.php
@@ -1956,11 +1956,7 @@ function readfile_accel($file, $mimetype, $accelerate) {
     header('Last-Modified: '. gmdate('D, d M Y H:i:s', $lastmodified) .' GMT');
 
     if (is_object($file)) {
-        if (empty($_SERVER['HTTP_RANGE'])) {
-            // Use Etag only when not byteserving,
-            // is it tag of this range or whole file?
-            header('Etag: ' . $file->get_contenthash());
-        }
+        header('ETag: ' . $file->get_contenthash());
         if (isset($_SERVER['HTTP_IF_NONE_MATCH']) and $_SERVER['HTTP_IF_NONE_MATCH'] === $file->get_contenthash()) {
             header('HTTP/1.1 304 Not Modified');
             return;
@@ -2610,10 +2606,6 @@ function byteserving_send_file($handle, $mimetype, $ranges, $filesize) {
     // better turn off any kind of compression and buffering
     @ini_set('zlib.output_compression', 'Off');
 
-    // Remove Etag because is is not strictly defined for byteserving,
-    // is it tag of this range or whole file?
-    header_remove('Etag');
-
     $chunksize = 1*(1024*1024); // 1MB chunks - must be less than 2MB!
     if ($handle === false) {
         die;
diff --git a/lib/xsendfilelib.php b/lib/xsendfilelib.php
index 5c254856090..3a563fd892a 100644
--- a/lib/xsendfilelib.php
+++ b/lib/xsendfilelib.php
@@ -68,12 +68,6 @@ function xsendfile($filepath) {
         }
     }
 
-    // Remove Etag because is is not strictly defined for byteserving,
-    // is it tag of this range or whole file?
-    if (!empty($_SERVER['HTTP_RANGE'])) {
-        header_remove('Etag');
-    }
-
     if ($CFG->xsendfile === 'X-LIGHTTPD-send-file') {
         // http://redmine.lighttpd.net/projects/lighttpd/wiki/X-LIGHTTPD-send-file says 1.4 it does not support byteserving
         header('Accept-Ranges: none');

From bf4a95e6a3a84b35b5a9efbe903c9c6f9523854a Mon Sep 17 00:00:00 2001
From: Matteo Scaramuccia <moodle@matteoscaramuccia.com>
Date: Sat, 1 Jun 2013 12:34:40 +0200
Subject: [PATCH 2/2] MDL-39832 Files: Fixed ETag format according with
 RFC2616.

ETag must be double quoted,
http://tools.ietf.org/html/rfc2616#section-3.11:

      entity-tag = [ weak ] opaque-tag
      weak       = "W/"
      opaque-tag = quoted-string
---
 lib/filelib.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/filelib.php b/lib/filelib.php
index 1820beac83c..24aa51970af 100644
--- a/lib/filelib.php
+++ b/lib/filelib.php
@@ -1956,7 +1956,7 @@ function readfile_accel($file, $mimetype, $accelerate) {
     header('Last-Modified: '. gmdate('D, d M Y H:i:s', $lastmodified) .' GMT');
 
     if (is_object($file)) {
-        header('ETag: ' . $file->get_contenthash());
+        header('Etag: "' . $file->get_contenthash() . '"');
         if (isset($_SERVER['HTTP_IF_NONE_MATCH']) and $_SERVER['HTTP_IF_NONE_MATCH'] === $file->get_contenthash()) {
             header('HTTP/1.1 304 Not Modified');
             return;