inc/httputils.php

   1 <?php
   2 /**
   3  * Utilities for handling HTTP related tasks
   4  *
   5  * @license    GPL 2 (http://www.gnu.org/licenses/gpl.html)
   6  * @author     Andreas Gohr <andi@splitbrain.org>
   7  */
   8
   9 define('HTTP_MULTIPART_BOUNDARY','D0KuW1K1B0uNDARY');
  10 define('HTTP_HEADER_LF',"\r\n");
  11 define('HTTP_CHUNK_SIZE',16*1024);
  12
  13 /**
  14  * Checks and sets HTTP headers for conditional HTTP requests
  15  *
  16  * @author   Simon Willison <swillison@gmail.com>
  17  * @link     http://simon.incutio.com/archive/2003/04/23/conditionalGet
  18  * @param    timestamp $timestamp lastmodified time of the cache file
  19  * @returns  void or exits with previously header() commands executed
  20  */
  21 function http_conditionalRequest($timestamp){
  22     // A PHP implementation of conditional get, see
  23     //   http://fishbowl.pastiche.org/archives/001132.html
  24     $last_modified = substr(gmdate('r', $timestamp), 0, -5).'GMT';
  25     $etag = '"'.md5($last_modified).'"';
  26     // Send the headers
  27     header("Last-Modified: $last_modified");
  28     header("ETag: $etag");
  29     // See if the client has provided the required headers
  30     if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])){
  31         $if_modified_since = stripslashes($_SERVER['HTTP_IF_MODIFIED_SINCE']);
  32     }else{
  33         $if_modified_since = false;
  34     }
  35
  36     if (isset($_SERVER['HTTP_IF_NONE_MATCH'])){
  37         $if_none_match = stripslashes($_SERVER['HTTP_IF_NONE_MATCH']);
  38     }else{
  39         $if_none_match = false;
  40     }
  41
  42     if (!$if_modified_since && !$if_none_match){
  43         return;
  44     }
  45
  46     // At least one of the headers is there - check them
  47     if ($if_none_match && $if_none_match != $etag) {
  48         return; // etag is there but doesn't match
  49     }
  50
  51     if ($if_modified_since && $if_modified_since != $last_modified) {
  52         return; // if-modified-since is there but doesn't match
  53     }
  54
  55     // Nothing has changed since their last request - serve a 304 and exit
  56     header('HTTP/1.0 304 Not Modified');
  57
  58     // don't produce output, even if compression is on
  59     @ob_end_clean();
  60     exit;
  61 }
  62
  63 /**
  64  * Let the webserver send the given file vi x-sendfile method
  65  *
  66  * @author Chris Smith <chris.eureka@jalakai.co.uk>
  67  * @returns  void or exits with previously header() commands executed
  68  */
  69 function http_sendfile($file) {
  70     global $conf;
  71
  72     //use x-sendfile header to pass the delivery to compatible webservers
  73     if($conf['xsendfile'] == 1){
  74         header("X-LIGHTTPD-send-file: $file");
  75         ob_end_clean();
  76         exit;
  77     }elseif($conf['xsendfile'] == 2){
  78         header("X-Sendfile: $file");
  79         ob_end_clean();
  80         exit;
  81     }elseif($conf['xsendfile'] == 3){
  82         header("X-Accel-Redirect: $file");
  83         ob_end_clean();
  84         exit;
  85     }
  86
  87     return false;
  88 }
  89
  90 /**
  91  * Send file contents supporting rangeRequests
  92  *
  93  * This function exits the running script
  94  *
  95  * @param ressource $fh - file handle for an already open file
  96  * @param int $size     - size of the whole file
  97  * @param int $mime     - MIME type of the file
  98  *
  99  * @author Andreas Gohr <andi@splitbrain.org>
 100  */
 101 function http_rangeRequest($fh,$size,$mime){
 102     $ranges  = array();
 103     $isrange = false;
 104
 105     header('Accept-Ranges: bytes');
 106
 107     if(!isset($_SERVER['HTTP_RANGE'])){
 108         // no range requested - send the whole file
 109         $ranges[] = array(0,$size,$size);
 110     }else{
 111         $t = explode('=', $_SERVER['HTTP_RANGE']);
 112         if (!$t[0]=='bytes') {
 113             // we only understand byte ranges - send the whole file
 114             $ranges[] = array(0,$size,$size);
 115         }else{
 116             $isrange = true;
 117             // handle multiple ranges
 118             $r = explode(',',$t[1]);
 119             foreach($r as $x){
 120                 $p = explode('-', $x);
 121                 $start = (int)$p[0];
 122                 $end   = (int)$p[1];
 123                 if (!$end) $end = $size - 1;
 124                 if ($start > $end || $start > $size || $end > $size){
 125                     header('HTTP/1.1 416 Requested Range Not Satisfiable');
 126                     print 'Bad Range Request!';
 127                     exit;
 128                 }
 129                 $len = $end - $start + 1;
 130                 $ranges[] = array($start,$end,$len);
 131             }
 132         }
 133     }
 134     $parts = count($ranges);
 135
 136     // now send the type and length headers
 137     if(!$isrange){
 138         header("Content-Type: $mime",true);
 139     }else{
 140         header('HTTP/1.1 206 Partial Content');
 141         if($parts == 1){
 142             header("Content-Type: $mime",true);
 143         }else{
 144             header('Content-Type: multipart/byteranges; boundary='.HTTP_MULTIPART_BOUNDARY,true);
 145         }
 146     }
 147
 148     // send all ranges
 149     for($i=0; $i<$parts; $i++){
 150         list($start,$end,$len) = $ranges[$i];
 151
 152         // multipart or normal headers
 153         if($parts > 1){
 154             echo HTTP_HEADER_LF.'--'.HTTP_MULTIPART_BOUNDARY.HTTP_HEADER_LF;
 155             echo "Content-Type: $mime".HTTP_HEADER_LF;
 156             echo "Content-Range: bytes $start-$end/$size".HTTP_HEADER_LF;
 157             echo HTTP_HEADER_LF;
 158         }else{
 159             header("Content-Length: $len");
 160             if($isrange){
 161                 header("Content-Range: bytes $start-$end/$size");
 162             }
 163         }
 164
 165         // send file content
 166         fseek($fh,$start); //seek to start of range
 167         $chunk = ($len > HTTP_CHUNK_SIZE) ? HTTP_CHUNK_SIZE : $len;
 168         while (!feof($fh) && $chunk > 0) {
 169             @set_time_limit(30); // large files can take a lot of time
 170             print fread($fh, $chunk);
 171             flush();
 172             $len -= $chunk;
 173             $chunk = ($len > HTTP_CHUNK_SIZE) ? HTTP_CHUNK_SIZE : $len;
 174         }
 175     }
 176     if($parts > 1){
 177         echo HTTP_HEADER_LF.'--'.HTTP_MULTIPART_BOUNDARY.'--'.HTTP_HEADER_LF;
 178     }
 179
 180     // everything should be done here, exit
 181     exit;
 182 }
 183
 184 /**
 185  * Check for a gzipped version and create if necessary
 186  *
 187  * return true if there exists a gzip version of the uncompressed file
 188  * (samepath/samefilename.sameext.gz) created after the uncompressed file
 189  *
 190  * @author Chris Smith <chris.eureka@jalakai.co.uk>
 191  */
 192 function http_gzip_valid($uncompressed_file) {
 193     $gzip = $uncompressed_file.'.gz';
 194     if (filemtime($gzip) < filemtime($uncompressed_file)) {    // filemtime returns false (0) if file doesn't exist
 195         return copy($uncompressed_file, 'compress.zlib://'.$gzip);
 196     }
 197
 198     return true;
 199 }