1 <?php if (!defined('PmWiki')) exit();
2 /*  Copyright 2006-2020 Patrick R. Michaud (pmichaud@pobox.com)
3     This file is part of PmWiki; you can redistribute it and/or modify
4     it under the terms of the GNU General Public License as published
5     by the Free Software Foundation; either version 2 of the License, or
6     (at your option) any later version.  See pmwiki.php for full details.
7 
8     Script maintained by Petko YOTOV www.pmwiki.org/petko
9 */
10 
11 ## Browser cache-control.  If this is a cacheable action (e.g., browse,
12 ## diff), then set the Last-Modified header to the time the site was 
13 ## last modified.  If the browser has provided us with a matching 
14 ## If-Modified-Since request header, we can return 304 Not Modified.
15 SDV($LastModFile,"$WorkDir/.lastmod");
16 if (!$LastModFile) return;
17 
18 $LastModTime = @filemtime($LastModFile);
19 foreach(get_included_files() as $f) 
20   { $v = @filemtime($f); if ($v > $LastModTime) $LastModTime = $v; }
21 
22 if (@$EnableIMSCaching) {
23   SDV($IMSCookie, $CookiePrefix.'imstime');
24   SDV($IMSCookieExpires, $Now + 60*60*24*30);
25   SDV($IMSInvalidators, array('authpw', 'author'));
26   $LogoutCookies[] = $IMSCookie;
27 
28   if ($IMSCookie) {
29     $IMSTime = @$_COOKIE[$IMSCookie];
30     if ($IMSTime < $LastModTime
31         || array_intersect($IMSInvalidators, array_keys($_POST))) {
32       $IMSTime = $Now; 
33       pmsetcookie($IMSCookie, $IMSTime, $IMSCookieExpires, '/');
34     }
35   } else $IMSTime = $LastModTime;
36 
37   if (in_array($action, (array)$CacheActions)) {
38     $HTTPLastMod = gmdate('D, d M Y H:i:s \G\M\T',$IMSTime);
39     $HTTPHeaders[] = "Cache-Control: no-cache";
40     $HTTPHeaders[] = "Last-Modified: $HTTPLastMod";
41     if (@$_SERVER['HTTP_IF_MODIFIED_SINCE']==$HTTPLastMod) {
42       header("HTTP/1.0 304 Not Modified");
43       header("Cache-Control: no-cache");
44       header("Expires: ");
45       header("Last-Modified: $HTTPLastMod");
46       exit(); 
47     }
48   }
49 }
50 
51 if ($NoHTMLCache 
52     || !@$PageCacheDir
53     || count($_POST) > 0
54     || count($_GET) > 1
55     || (count($_GET) == 1 && !@$_GET['n'])) { $NoHTMLCache |= 1; return; }
56 
57 mkdirp($PageCacheDir);
58 if (!file_exists("$PageCacheDir/.htaccess") 
59     && $fp = @fopen("$PageCacheDir/.htaccess", "w"))
60   { fwrite($fp, $DenyHtaccessContent); fclose($fp); }
61 
62 SDV($PageCacheFileFmt, "%s/%s,cache");
63 SDV($PageCacheFile, sprintf($PageCacheFileFmt, $PageCacheDir, $pagename));
64 
65 if (file_exists($PageCacheFile) && @filemtime($PageCacheFile) < $LastModTime) 
66   @unlink($PageCacheFile);
67