PHP classes for encoding/decoding data to/from the BitTorrent format. Tracker related classes can be found here:
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PHP_BitTorrent is a set of components that can be used to interact with torrent files (read+write) and encode/decode to/from the BitTorrent format.

Current Build Status


PHP_BitTorrent requires PHP 5.3.x or above. The recommended version is 5.3.2 or newer.


PHP_BitTorrent can be installed using PEAR, Composer or PHAR.


sudo pear config-set auto_discover 1
sudo pear install --alldeps


Simply specify christeredvartsen/php-bittorrent in your dependencies. The different versions are listed at the Packagist site.


You can also download php-bittorrent.phar and simply require that file where you want to use PHP_BitTorrent.

require '/path/to/php-bittorrent.phar';

$encoder = new PHP\BitTorrent\Encoder();

// ...

Using the PHP BitTorrent API


PHP BitTorrent does not come with its own autoloader, so you will need to use a PSR-0 compatible autoloader for everything to work as expected, or provide your own require[_once] statements. An example of such an autoloader can be found here. When using PHP_BitTorrent as a PHAR archive you will only need to require the archive itself, and when installed using Composer you can simply require the autoloader generated by Composer (vendor/autoload.php).

Encode PHP variables

$encoder = new PHP\BitTorrent\Encoder();

var_dump($encoder->encodeString('Some string')); // string(14) "11:Some string"
var_dump($encoder->encodeInteger(42)); // int(42)
var_dump($encoder->encodeList(array(1, 2, 3)); // string(11) "li1ei2ei3ee"
var_dump($encoder->encodeDictionary(array('foo' => 'bar', 'bar' => 'foo')); // string(22) "d3:foo3:bar3:bar3:fooe"

There is also a convenience method simply called encode in the PHP\BitTorrent\Encoder class that can be used to encode all encodable variables (integers, strings and arrays).

Decode BitTorrent encoded data

$encoder = new PHP\BitTorrent\Encoder();
$decoder = new PHP\BitTorrent\Decoder($encoder); // The decoder needs an encoder for some methods

var_dump($decoder->decodeString('11:Some string')); // string(11) "Some string"
var_dump($decoder->decodeInteger('i42e')); // int(42)
var_dump($decoder->decodeList('li1ei2ei3ee'); // array(3) { [0]=> int(1) [1]=> int(2) [2]=> int(3) }
var_dump($decoder->decodeDictionary('d3:foo3:bar3:bar3:fooe'); // array(2) { ["foo"]=> string(3) "bar" ["bar"]=> string(3) "foo" }

There is also a convenience method called decode that can decode any BitTorrent encoded data.

Decode torrent files

The decoder class also has a method for decoding a torrent file (which is an encoded dictionary):

$encoder = new PHP\BitTorrent\Encoder();
$decoder = new PHP\BitTorrent\Decoder($encoder);

$decodedFile = $decoder->decodeFile('/path/to/file.torrent');

Create new torrent files and open existing ones

The PHP\BitTorrent\Torrent class represents a torrent file and can be used to create torrent files.

$torrent = PHP\BitTorrent\Torrent::createFromPath('/path/to/files', 'http://tracker/announce.php');

$torrent->setComment('Some comment')

The class can also load a torrent file:

$torrent = PHP\BitTorrent\Torrent::createFromTorrentFile('/path/to/file.torrent');

$torrent->setAnnounce('http://tracker/announce.php') // Override announce in original file
        ->setComment('Some comment') // Override commend in original file
        ->save('/save/to/path/file.torrent'); // Save to a new file

32-bit platforms

On 32-bit platforms these components work slightly different with regards to integers:

  • The generic PHP\BitTorrent\Encoder::encode method will encode both integers and strings containing numerics as strings (strings containing floating point values are still treated as regular strings).
  • The PHP\BitTorrent\Decoder::decodeInteger method will return values as strings, and not integers.
  • The PHP\BitTorrent\Torrent::getSize method will use the bcadd function to calculate the size of the files in the torrent.