/secured/fetch.php

<?php
include 'editor_conf.php';
include 'intranet_check_cookie.php';
if($is_admin){
/**
 * DokuWiki media passthrough file
 *
 * @license    GPL 2 (http://www.gnu.org/licenses/gpl.html)
 * @author     Andreas Gohr <andi@splitbrain.org>
 */

  //echo 'is admin = ' . $is_admin;

  if(!defined('CHUNK_SIZE')) define('CHUNK_SIZE',16*1024);

  //get input
  $FILE  = $basepath.$_GET['media']; // no cleaning except control chars - maybe external
  $CACHE  = calc_cache($_REQUEST['cache']);

  //check file existance
  if(!@file_exists($FILE)){
    header("HTTP/1.0 404 Not Found");
    //FIXME add some default broken image
    print 'Not Found';
    exit;
  }

  // finally send the file to the client
  sendFile($FILE,$CACHE);
}

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

/**
 * Set headers and send the file to the client
 *
 * @author Andreas Gohr <andi@splitbrain.org>
 * @author Ben Coburn <btcoburn@silicodon.net>
 */
function sendFile($file,$cache){

/*
  echo 'Start Send File <br>';
  echo 'Current path = ' . getcwd() . '<br>';
  echo 'File name = '.$file . '<br>';
  echo 'cache = '.$cache . '<br>';
*/
  global $conf;
  $fmtime = filemtime($file);
  // send headers
  header("Content-Type: application/octet-stream");
  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');
  }

  header('Content-Disposition: attachment; filename="'.basename($file).'";');

  //send important headers first, script stops here if '304 Not Modified' response
  http_conditionalRequest($fmtime);  

  //support download continueing
  header('Accept-Ranges: bytes');
  list($start,$len) = http_rangeRequest(filesize($file));

  // send file contents
  $fp = @fopen($file,"rb");
  if($fp){
    fseek($fp,$start); //seek to start of range

    $chunk = ($len > CHUNK_SIZE) ? CHUNK_SIZE : $len;
    while (!feof($fp) && $chunk > 0) {
      @set_time_limit(30); // large files can take a lot of time
      print fread($fp, $chunk);
      flush();
      $len -= $chunk;
      $chunk = ($len > CHUNK_SIZE) ? CHUNK_SIZE : $len;
    }
    fclose($fp);
  }else{
    header("HTTP/1.0 500 Internal Server Error");
    print "Could not read $file - bad permissions?";
  }

}

/**
 * Checks and sets HTTP headers for conditional HTTP requests
 *
 * @author   Simon Willison <swillison@gmail.com>
 * @link     http://simon.incutio.com/archive/2003/04/23/conditionalGet
 * @param    timestamp $timestamp lastmodified time of the cache file
 * @returns  void or void with previously header() commands executed
 */
function http_conditionalRequest($timestamp){ 
  // A PHP implementation of conditional get, see
  //   http://fishbowl.pastiche.org/archives/001132.html
  $last_modified = substr(gmdate('r', $timestamp), 0, -5).'GMT';   
  $etag = '"'.md5($last_modified).'"';
  // Send the headers
  header("Last-Modified: $last_modified");
  header("ETag: $etag");
  // See if the client has provided the required headers
  if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])){
    $if_modified_since = stripslashes($_SERVER['HTTP_IF_MODIFIED_SINCE']);
  }else{
    $if_modified_since = false;
  }
     
  if (isset($_SERVER['HTTP_IF_NONE_MATCH'])){
    $if_none_match = stripslashes($_SERVER['HTTP_IF_NONE_MATCH']);
  }else{
    $if_none_match = false;
  }
    
  if (!$if_modified_since && !$if_none_match){
    return;
  }  

  // At least one of the headers is there - check them
  if ($if_none_match && $if_none_match != $etag) {
    return; // etag is there but doesn't match
  }
  
  if ($if_modified_since && $if_modified_since != $last_modified) {
    return; // if-modified-since is there but doesn't match
  }
  
  // Nothing has changed since their last request - serve a 304 and exit
  header('HTTP/1.0 304 Not Modified');
  
  // don't produce output, even if compression is on
  ob_end_clean();
  exit;
}  
  


/**
 * Checks and sets headers to handle range requets
 *
 * @author  Andreas Gohr <andi@splitbrain.org>
 * @returns array The start byte and the amount of bytes to send
 */
function http_rangeRequest($size){
  if(!isset($_SERVER['HTTP_RANGE'])){
    // no range requested - send the whole file
    header("Content-Length: $size");
    return array(0,$size);
  }

  $t = explode('=', $_SERVER['HTTP_RANGE']);
  if (!$t[0]=='bytes') {
    // we only understand byte ranges - send the whole file
    header("Content-Length: $size");
    return array(0,$size);
  }

  $r = explode('-', $t[1]);
  $start = (int)$r[0];
  $end = (int)$r[1];
  if (!$end) $end = $size - 1;
  if ($start > $end || $start > $size || $end > $size){
    header('HTTP/1.1 416 Requested Range Not Satisfiable');
    print 'Bad Range Request!';
    exit;
  }

  $tot = $end - $start + 1;
  header('HTTP/1.1 206 Partial Content');
  header("Content-Range: bytes {$start}-{$end}/{$size}");
  header("Content-Length: $tot");

  return array($start,$tot);
}

/**
 * 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
}

/**
 * Download a remote file and return local filename
 *
 * returns false if download fails. Uses cached file if available and
 * wanted
 *
 * @author  Andreas Gohr <andi@splitbrain.org>
 * @author  Pavel Vitis <Pavel.Vitis@seznam.cz>
 */
function get_from_URL($url,$ext,$cache){
  global $conf;

  // if no cache or fetchsize just redirect
  if ($cache==0)           return false;
  if (!$conf['fetchsize']) return false;

  $local = getCacheName(strtolower($url),".media.$ext");
  $mtime = @filemtime($local); // 0 if not exists

  //decide if download needed:
  if( ($mtime == 0) ||                           // cache does not exist
      ($cache != -1 && $mtime < time()-$cache)   // 'recache' and cache has expired
    ){
      if(image_download($url,$local)){
        return $local;
      }else{
        return false;
      }
  }

  //if cache exists use it else
  if($mtime) return $local;

  //else return false
  return false;
}

/**
 * Download image files
 *
 * @author Andreas Gohr <andi@splitbrain.org>
 */
function image_download($url,$file){
  global $conf;
  $http = new DokuHTTPClient();
  $http->max_bodysize = $conf['fetchsize'];
  $http->timeout = 25; //max. 25 sec
  $http->header_regexp = '!\r\nContent-Type: image/(jpe?g|gif|png)!i';

  $data = $http->get($url);
  if(!$data) return false;

  $fileexists = @file_exists($file);
  $fp = @fopen($file,"w");
  if(!$fp) return false;
  fwrite($fp,$data);
  fclose($fp);
  if(!$fileexists and $conf['fperm']) chmod($file, $conf['fperm']);

  // check if it is really an image
  $info = @getimagesize($file);
  if(!$info){
    @unlink($file);
    return false;
  }

  return true;
}

/**
 * Checks if the given amount of memory is available
 *
 * If the memory_get_usage() function is not available the
 * function just assumes $bytes of already allocated memory
 *
 * @param  int $mem  Size of memory you want to allocate in bytes
 * @param  int $used already allocated memory (see above)
 * @author Filip Oscadal <webmaster@illusionsoftworks.cz>
 * @author Andreas Gohr <andi@splitbrain.org>
 */
function is_mem_available($mem,$bytes=1048576){
  $limit = trim(ini_get('memory_limit'));
  if(empty($limit)) return true; // no limit set!

  // parse limit to bytes
  $limit = php_to_byte($limit);

  // get used memory if possible
  if(function_exists('memory_get_usage')){
    $used = memory_get_usage();
  }

  if($used+$mem > $limit){
    return false;
  }

  return true;
}

//Setup VIM: ex: et ts=2 enc=utf-8 :
?>