git.m6w6.name Git - m6w6/ext-http/blob - lib/BigGet.php

   1 <?php
   2
   3 /**
   4  * BigGet - download big files efficiently
   5  * $Id$
   6  *
   7  * @copyright   Michael Wallner, <mike@iworks.at>
   8  * @license     BSD, revised
   9  * @version     $Revision$
  10  */
  11 class BigGet extends HttpRequestPool
  12 {
  13     /**
  14      * File split size
  15      */
  16     const SIZE = 1048576;
  17
  18     /**
  19      * Parallel Request count
  20      */
  21     const RMAX = 5;
  22
  23     /**
  24      * Whether to output debug messages
  25      *
  26      * @var bool
  27      */
  28     public $dbg = false;
  29
  30     /**
  31      * URL
  32      *
  33      * @var string
  34      */
  35     private $url;
  36
  37     /**
  38      * Temp file prefix
  39      *
  40      * @var string
  41      */
  42     private $tmp;
  43
  44     /**
  45      * Size of requested resource
  46      *
  47      * @var int
  48      */
  49     private $size;
  50
  51     /**
  52      * Whether the requests have been sent
  53      *
  54      * @var bool
  55      */
  56     private $sent = false;
  57
  58     /**
  59      * Request counter
  60      *
  61      * @var int
  62      */
  63     private $count = 0;
  64
  65     /**
  66      * Static constructor
  67      *
  68      * @param string $url
  69      * @param string $tmp
  70      * @return BigGet
  71      * @throws Exception
  72      */
  73     public static function url($url, $tmp = '/tmp')
  74     {
  75         $head = new HttpRequest($url, HttpRequest::METH_HEAD);
  76         $headers = $head->send()->getHeaders();
  77
  78         if (200 != $head->getResponseCode()) {
  79             throw new HttpException("Did not receive '200 Ok' from HEAD $url");
  80         }
  81         if (!isset($headers['Accept-Ranges'])) {
  82             throw new HttpException("Did not receive an Accept-Ranges header from HEAD $url");
  83         }
  84         if (!isset($headers['Content-Length'])) {
  85             throw new HttpException("Did not receive a Content-Length header from HEAD $url");
  86         }
  87
  88         $bigget = new BigGet;
  89         $bigget->url = $url;
  90         $bigget->tmp = tempnam($tmp, 'BigGet.');
  91         $bigget->size = $headers['Content-Length'];
  92         return $bigget;
  93     }
  94
  95     /**
  96      * Save the resource to a file
  97      *
  98      * @param string $file
  99      * @return bool
 100      * @throws Exception
 101      */
 102     public function saveTo($file)
 103     {
 104         $this->sent or $this->send();
 105
 106         if ($w = fopen($this->tmp, 'wb')) {
 107
 108             $this->dbg && print "\nCopying temp files to $file ...\n";
 109
 110             foreach (glob($this->tmp .".????") as $tmp) {
 111
 112                 $this->dbg && print "\t$tmp\n";
 113
 114                 if ($r = fopen($tmp, 'rb')) {
 115                     stream_copy_to_stream($r, $w);
 116                     fclose($r);
 117                 }
 118                 unlink($tmp);
 119             }
 120             fclose($w);
 121             rename($this->tmp, $file);
 122
 123             $this->dbg && print "\nDone.\n";
 124
 125             return true;
 126         }
 127         return false;
 128     }
 129
 130     /**
 131      * Overrides HttpRequestPool::send()
 132      *
 133      * @return void
 134      * @throws Exception
 135      */
 136     public function send()
 137     {
 138         $this->sent = true;
 139
 140         // use max RMAX simultanous requests with a req size of SIZE
 141         while ($this->count < self::RMAX && -1 != $offset = $this->getRangeOffset()) {
 142             $this->attachNew($offset);
 143         }
 144
 145         while ($this->socketPerform()) {
 146             if (!$this->socketSelect()) {
 147                 throw new HttpSocketException;
 148             }
 149         }
 150     }
 151
 152     /**
 153      * Overrides HttpRequestPool::socketPerform()
 154      *
 155      * @return bool
 156      */
 157     protected function socketPerform()
 158     {
 159         $rs = parent::socketPerform();
 160
 161         foreach ($this->getFinishedRequests() as $r) {
 162             $this->detach($r);
 163
 164             if (206 != $rc = $r->getResponseCode()) {
 165                 throw new HttpException("Unexpected response code: $rc");
 166             }
 167
 168             file_put_contents(sprintf("%s.%04d", $this->tmp, $r->id), $r->getResponseBody());
 169
 170             if (-1 != $offset = $this->getRangeOffset()) {
 171                 $this->attachNew($offset);
 172             }
 173         }
 174
 175         return $rs;
 176     }
 177
 178     private function attachNew($offset)
 179     {
 180         $stop = min($this->count * self::SIZE + self::SIZE, $this->size) - 1;
 181
 182         $this->dbg && print "Attaching new request to get range: $offset-$stop\n";
 183
 184         $req = new BigGetRequest(
 185             $this->url,
 186             HttpRequest::METH_GET,
 187             array(
 188                 'headers' => array(
 189                     'Range' => "bytes=$offset-$stop"
 190                 )
 191             )
 192         );
 193         $this->attach($req);
 194         $req->id = $this->count++;
 195     }
 196
 197     private function getRangeOffset()
 198     {
 199         return ($this->size >= $start = $this->count * self::SIZE) ? $start : -1;
 200     }
 201 }
 202
 203
 204 /**
 205  * BigGet request
 206  * @ignore
 207  */
 208 class BigGetRequest extends HttpRequest
 209 {
 210     public $id;
 211 }
 212
 213 ?>