xref: /dokuwiki/lib/exe/fetch.php (revision 3b399a1bd4eba22429d676bddd759ed762c9e80e)

<?php
/**
 * DokuWiki media passthrough file
 *
 * @license    GPL 2 (http://www.gnu.org/licenses/gpl.html)
 * @author     Andreas Gohr <andi@splitbrain.org>
 */

if(!defined('DOKU_INC')) define('DOKU_INC', dirname(__FILE__).'/../../');
define('DOKU_DISABLE_GZIP_OUTPUT', 1);
require_once(DOKU_INC.'inc/init.php');
//close session
session_write_close();

$mimetypes = getMimeTypes();

//get input
$MEDIA  = stripctl(getID('media', false)); // no cleaning except control chars - maybe external
$CACHE  = calc_cache($INPUT->str('cache'));
$WIDTH  = $INPUT->int('w');
$HEIGHT = $INPUT->int('h');
$REV    = & $INPUT->ref('rev');
//sanitize revision
$REV = preg_replace('/[^0-9]/', '', $REV);

list($EXT, $MIME, $DL) = mimetype($MEDIA, false);
if($EXT === false) {
    $EXT  = 'unknown';
    $MIME = 'application/octet-stream';
    $DL   = true;
}

// check for permissions, preconditions and cache external files
list($STATUS, $STATUSMESSAGE) = checkFileStatus($MEDIA, $FILE, $REV);

// prepare data for plugin events
$data = array(
    'media'         => $MEDIA,
    'file'          => $FILE,
    'orig'          => $FILE,
    'mime'          => $MIME,
    'download'      => $DL,
    'cache'         => $CACHE,
    'ext'           => $EXT,
    'width'         => $WIDTH,
    'height'        => $HEIGHT,
    'status'        => $STATUS,
    'statusmessage' => $STATUSMESSAGE,
);

// handle the file status
$evt = new Doku_Event('FETCH_MEDIA_STATUS', $data);
if($evt->advise_before()) {
    // redirects
    if($data['status'] > 300 && $data['status'] <= 304) {
        send_redirect($data['statusmessage']);
    }
    // send any non 200 status
    if($data['status'] != 200) {
        header('HTTP/1.0 '.$data['status'].' '.$data['statusmessage']);
    }
    // die on errors
    if($data['status'] > 203) {
        print $data['statusmessage'];
        exit;
    }
}
$evt->advise_after();
unset($evt);

//handle image resizing/cropping
if((substr($MIME, 0, 5) == 'image') && $WIDTH) {
    if($HEIGHT) {
        $data['file'] = $FILE = media_crop_image($data['file'], $EXT, $WIDTH, $HEIGHT);
    } else {
        $data['file'] = $FILE = media_resize_image($data['file'], $EXT, $WIDTH, $HEIGHT);
    }
}

// finally send the file to the client
$evt = new Doku_Event('MEDIA_SENDFILE', $data);
if($evt->advise_before()) {
    sendFile($data['file'], $data['mime'], $data['download'], $data['cache']);
}
// Do something after the download finished.
$evt->advise_after();

/* ------------------------------------------------------------------------ */

/**
 * Set headers and send the file to the client
 *
 * @author Andreas Gohr <andi@splitbrain.org>
 * @author Ben Coburn <btcoburn@silicodon.net>
 */
function sendFile($file, $mime, $dl, $cache) {
    global $conf;
    $fmtime = @filemtime($file);
    // send headers
    header("Content-Type: $mime");
    // smart http caching headers
    if($cache == -1) {
        // cache
        // cachetime or one hour
        header('Expires: '.gmdate("D, d M Y H:i:s", time() + max($conf['cachetime'], 3600)).' GMT');
        header('Cache-Control: public, proxy-revalidate, no-transform, max-age='.max($conf['cachetime'], 3600));
        header('Pragma: public');
    } else if($cache > 0) {
        // recache
        // remaining cachetime + 10 seconds so the newly recached media is used
        header('Expires: '.gmdate("D, d M Y H:i:s", $fmtime + $conf['cachetime'] + 10).' GMT');
        header('Cache-Control: public, proxy-revalidate, no-transform, max-age='.max($fmtime - time() + $conf['cachetime'] + 10, 0));
        header('Pragma: public');
    } else if($cache == 0) {
        // nocache
        header('Cache-Control: must-revalidate, no-transform, post-check=0, pre-check=0');
        header('Pragma: public');
    }
    //send important headers first, script stops here if '304 Not Modified' response
    http_conditionalRequest($fmtime);

    //download or display?
    if($dl) {
        header('Content-Disposition: attachment; filename="'.utf8_basename($file).'";');
    } else {
        header('Content-Disposition: inline; filename="'.utf8_basename($file).'";');
    }

    //use x-sendfile header to pass the delivery to compatible webservers
    if(http_sendfile($file)) exit;

    // send file contents
    $fp = @fopen($file, "rb");
    if($fp) {
        http_rangeRequest($fp, filesize($file), $mime);
    } else {
        header("HTTP/1.0 500 Internal Server Error");
        print "Could not read $file - bad permissions?";
    }
}

/**
 * Check for media for preconditions and return correct status code
 *
 * READ: MEDIA, MIME, EXT, CACHE
 * WRITE: MEDIA, FILE, array( STATUS, STATUSMESSAGE )
 *
 * @author Gerry Weissbach <gerry.w@gammaproduction.de>
 * @param $media reference to the media id
 * @param $file  reference to the file variable
 * @returns array(STATUS, STATUSMESSAGE)
 */
function checkFileStatus(&$media, &$file, $rev = '') {
    global $MIME, $EXT, $CACHE, $INPUT;

    //media to local file
    if(preg_match('#^(https?)://#i', $media)) {
        //check hash
        if(substr(md5(auth_cookiesalt().$media), 0, 6) !== $INPUT->str('hash')) {
            return array(412, 'Precondition Failed');
        }
        //handle external images
        if(strncmp($MIME, 'image/', 6) == 0) $file = media_get_from_URL($media, $EXT, $CACHE);
        if(!$file) {
            //download failed - redirect to original URL
            return array(302, $media);
        }
    } else {
        $media = cleanID($media);
        if(empty($media)) {
            return array(400, 'Bad request');
        }

        //check permissions (namespace only)
        if(auth_quickaclcheck(getNS($media).':X') < AUTH_READ) {
            return array(403, 'Forbidden');
        }
        $file = mediaFN($media, $rev);
    }

    //check file existance
    if(!@file_exists($file)) {
        return array(404, 'Not Found');
    }

    return array(200, null);
}

/**
 * Returns the wanted cachetime in seconds
 *
 * Resolves named constants
 *
 * @author  Andreas Gohr <andi@splitbrain.org>
 */
function calc_cache($cache) {
    global $conf;

    if(strtolower($cache) == 'nocache') return 0; //never cache
    if(strtolower($cache) == 'recache') return $conf['cachetime']; //use standard cache
    return -1; //cache endless
}

//Setup VIM: ex: et ts=2 :