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MDL-28708: Send 304 Not Modified response when browser If-Modified-Si…

…nce header is after file mtime
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1 parent 4f36324 commit f73c6bad2cc3017a9c21298560d688e8be3531da @tlevi tlevi committed with skodak Aug 11, 2011
Showing with 30 additions and 0 deletions.
  1. +30 −0 lib/filelib.php
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@@ -1728,6 +1728,21 @@ function send_file($path, $filename, $lifetime = 'default' , $filter=0, $pathiss
//try to disable automatic sid rewrite in cookieless mode
@ini_set("session.use_trans_sid", "false");
+ if ($lifetime > 0 && !empty($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
+ // get unixtime of request header; clip extra junk off first
+ $since = strtotime(preg_replace('/;.*$/','',$_SERVER["HTTP_IF_MODIFIED_SINCE"]));
+ if ($since && $since >= $lastmodified) {
+ header('HTTP/1.1 304 Not Modified');
+ header('Expires: '. gmdate('D, d M Y H:i:s', time() + $lifetime) .' GMT');
+ header('Cache-Control: max-age='.$lifetime);
+ header('Content-Type: '.$mimetype);
+ if ($dontdie) {
+ return;
+ }
+ die;
+ }
+ }
+
//do not put '@' before the next header to detect incorrect moodle configurations,
//error should be better than "weird" empty lines for admins/users
header('Last-Modified: '. gmdate('D, d M Y H:i:s', $lastmodified) .' GMT');
@@ -1928,6 +1943,21 @@ function send_stored_file($stored_file, $lifetime=86400 , $filter=0, $forcedownl
//try to disable automatic sid rewrite in cookieless mode
@ini_set("session.use_trans_sid", "false");
+ if ($lifetime > 0 && !empty($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
+ // get unixtime of request header; clip extra junk off first
+ $since = strtotime(preg_replace('/;.*$/','',$_SERVER["HTTP_IF_MODIFIED_SINCE"]));
+ if ($since && $since >= $lastmodified) {
+ header('HTTP/1.1 304 Not Modified');
+ header('Expires: '. gmdate('D, d M Y H:i:s', time() + $lifetime) .' GMT');
+ header('Cache-Control: max-age='.$lifetime);
+ header('Content-Type: '.$mimetype);
+ if ($dontdie) {
+ return;
+ }
+ die;
+ }
+ }
+
//do not put '@' before the next header to detect incorrect moodle configurations,
//error should be better than "weird" empty lines for admins/users
//TODO: should we remove all those @ before the header()? Are all of the values supported on all servers?

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