xref: /dokuwiki/inc/fetch.functions.php (revision 12d195ab7189878b41dc4d211befafc79ae402a6) 
1<?php
2/**
3 * Functions used by lib/exe/fetch.php
4 * (not included by other parts of dokuwiki)
5 */
6
7/**
8 * Set headers and send the file to the client
9 *
10 * The $cache parameter influences how long files may be kept in caches, the $public parameter
11 * influences if this caching may happen in public proxis or in the browser cache only FS#2734
12 *
13 * This function will abort the current script when a 304 is sent or file sending is handled
14 * through x-sendfile
15 *
16 * @author Andreas Gohr <andi@splitbrain.org>
17 * @author Ben Coburn <btcoburn@silicodon.net>
18 * @param string $file   local file to send
19 * @param string $mime   mime type of the file
20 * @param bool   $dl     set to true to force a browser download
21 * @param int    $cache  remaining cache time in seconds (-1 for $conf['cache'], 0 for no-cache)
22 * @param bool   $public is this a public ressource or a private one?
23 */
24function sendFile($file, $mime, $dl, $cache, $public = false) {
25    global $conf;
26    // send mime headers
27    header("Content-Type: $mime");
28
29    // calculate cache times
30    if($cache == -1) {
31        $maxage  = max($conf['cachetime'], 3600); // cachetime or one hour
32        $expires = time() + $maxage;
33    } else if($cache > 0) {
34        $maxage  = $cache; // given time
35        $expires = time() + $maxage;
36    } else { // $cache == 0
37        $maxage  = 0;
38        $expires = 0; // 1970-01-01
39    }
40
41    // smart http caching headers
42    if($maxage) {
43        if($public) {
44            // cache publically
45            header('Expires: '.gmdate("D, d M Y H:i:s", $expires).' GMT');
46            header('Cache-Control: public, proxy-revalidate, no-transform, max-age='.$maxage);
47            header('Pragma: public');
48        } else {
49            // cache in browser
50            header('Expires: '.gmdate("D, d M Y H:i:s", $expires).' GMT');
51            header('Cache-Control: private, no-transform, max-age='.$maxage);
52            header('Pragma: no-cache');
53        }
54    } else {
55        // no cache at all
56        header('Expires: Thu, 01 Jan 1970 00:00:00 GMT');
57        header('Cache-Control: no-cache, no-transform');
58        header('Pragma: no-cache');
59    }
60
61    //send important headers first, script stops here if '304 Not Modified' response
62    $fmtime = @filemtime($file);
63    http_conditionalRequest($fmtime);
64
65    //download or display?
66    if($dl) {
67        header('Content-Disposition: attachment; filename="'.utf8_basename($file).'";');
68    } else {
69        header('Content-Disposition: inline; filename="'.utf8_basename($file).'";');
70    }
71
72    //use x-sendfile header to pass the delivery to compatible webservers
73    if(http_sendfile($file)) exit;
74
75    // send file contents
76    $fp = @fopen($file, "rb");
77    if($fp) {
78        http_rangeRequest($fp, filesize($file), $mime);
79    } else {
80        http_status(500);
81        print "Could not read $file - bad permissions?";
82    }
83}
84
85/**
86 * Check for media for preconditions and return correct status code
87 *
88 * READ: MEDIA, MIME, EXT, CACHE
89 * WRITE: MEDIA, FILE, array( STATUS, STATUSMESSAGE )
90 *
91 * @author Gerry Weissbach <gerry.w@gammaproduction.de>
92 * @param $media reference to the media id
93 * @param $file  reference to the file variable
94 * @returns array(STATUS, STATUSMESSAGE)
95 */
96function checkFileStatus(&$media, &$file, $rev = '', $width=0, $height=0) {
97    global $MIME, $EXT, $CACHE, $INPUT;
98
99    //media to local file
100    if(preg_match('#^(https?)://#i', $media)) {
101        //check hash
102        if(substr(PassHash::hmac('md5', $media, auth_cookiesalt()), 0, 6) !== $INPUT->str('hash')) {
103            return array(412, 'Precondition Failed');
104        }
105        //handle external images
106        if(strncmp($MIME, 'image/', 6) == 0) $file = media_get_from_URL($media, $EXT, $CACHE);
107        if(!$file) {
108            //download failed - redirect to original URL
109            return array(302, $media);
110        }
111    } else {
112        $media = cleanID($media);
113        if(empty($media)) {
114            return array(400, 'Bad request');
115        }
116        // check token for resized images
117        if (($width || $height) && media_get_token($media, $width, $height) !== $INPUT->str('tok')) {
118            return array(412, 'Precondition Failed');
119        }
120
121        //check permissions (namespace only)
122        if(auth_quickaclcheck(getNS($media).':X') < AUTH_READ) {
123            return array(403, 'Forbidden');
124        }
125        $file = mediaFN($media, $rev);
126    }
127
128    //check file existance
129    if(!@file_exists($file)) {
130        return array(404, 'Not Found');
131    }
132
133    return array(200, null);
134}
135
136/**
137 * Returns the wanted cachetime in seconds
138 *
139 * Resolves named constants
140 *
141 * @author  Andreas Gohr <andi@splitbrain.org>
142 */
143function calc_cache($cache) {
144    global $conf;
145
146    if(strtolower($cache) == 'nocache') return 0; //never cache
147    if(strtolower($cache) == 'recache') return $conf['cachetime']; //use standard cache
148    return -1; //cache endless
149}
150