Skip to content
Fetching contributors…
Cannot retrieve contributors at this time
286 lines (213 sloc) 10.2 KB
AnyEvent::BitTorrent - Yet Another BitTorrent Client Module
use AnyEvent::BitTorrent;
my $client = AnyEvent::BitTorrent->new( path => 'some.torrent' );
This is a painfully simple BitTorrent client written on a whim that
implements the absolute basics. For a full list of what's currently
supported, what you will likely find in a future version, and what
you'll never get from this, see the section entitled "This Module is
The API, much like the module itself, is simple.
Anything you find by skimming the source is likely not ready for public
use and will be subject to change before `v1.0.0'. Here's the public
interface as of this version:
`new( ... )'
This constructor understands the following arguments:
This is the only required parameter. It's the path to a valid
.torrent file.
This is the base directory all data will be stored in and/or read
from. Multifile torrents will create another directory below this to
store all files.
By default, this is the current working directory when `new( ... )'
is called.
This is the preferred port local host binds and expects incoming
peers to connect to.
By default, this is a zero; the system will pick a port number
This is a subroutine called whenever a piece fails to pass
hashcheck. The callback is handed the piece's index.
This is a subroutine called whenever a piece passes its hashcheck.
The callback is handed the piece's index.
This must be one of the following:
This is the default. The client will attempt to create new
connections, make and fill requests, etc. This is normal client
In this state, connections will be made and accepted but no
piece requests will be made or filled. To resume full, normal
behavior, you must call `start( )'.
Everything is put on hold. No new outgoing connections are
attempted and incoming connections are rejected. To resume full,
normal behavior, you must call `start( )'.
This is the index returned by `piece_cache( )' in a previous
instance. Using this should make a complete resume system a trivial
`hashcheck( [...] )'
This method expects...
...a list of integers. You could use this to check a range of pieces (a
single file, for example).
$client->hashcheck( 1 .. 5, 34 .. 56 );
...a single integer. Only that specific piece is checked.
$client->hashcheck( 17 );
...nothing. All data related to this torrent will be checked.
$client->hashcheck( );
As pieces pass or fail, your `on_hash_pass' and `on_hash_fail' callbacks
are triggered.
`start( )'
Sends a 'started' event to trackers and starts performing as a client is
expected. New connections are made and accepted, requests are made and
filled, etc.
`stop( )'
Sends a stopped event to trackers, closes all connections, stops
attempting new outgoing connections, rejects incoming connections and
closes all open files.
`pause( )'
The client remains mostly active; new connections will be made and
accepted, etc. but no requests will be made or filled while the client
is paused.
`infohash( )'
Returns the 20-byte SHA1 hash of the value of the info key from the
metadata file.
`peerid( )'
Returns the 20 byte string used to identify the client. Please see the
spec below.
`port( )'
Returns the port number the client is listening on.
`size( )'
Returns the total size of all files described in the torrent's metadata.
Note that this value is recalculated every time you call this method. If
you need it more than occasionally, it may be best to cache it yourself.
`name( )'
Returns the UTF-8 encoded string the metadata suggests we save the file
(or directory, in the case of multi-file torrents) under.
`uploaded( )'
Returns the total amount uploaded to remote peers.
`downloaded( )'
Returns the total amount downloaded from other peers.
`left( )'
Returns the approximate amount based on the pieces we still want
multiplied by the size of pieces.
`piece_length( )'
Returns the number of bytes in each piece the file or files are split
into. For the purposes of transfer, files are split into fixed-size
pieces which are all the same length except for possibly the last one
which may be truncated.
`bitfield( )'
Returns a packed binary string in ascending order (ready for `vec()').
Each index that the client has is set to one and the rest are set to
`wanted( )'
Returns a packed binary string in ascending order (ready for `vec()').
Each index that the client has or simply does not want is set to zero
and the rest are set to one.
This value is calculated every time the method is called. Keep that in
`complete( )'
Returns true if we have downloaded everything we wanted which is not to
say that we have all data and can seed.
`seed( )'
Returns true if we have all data related to the torrent.
`files( )'
Returns a list of hash references with the following keys:
Which is the size of file in bytes.
Which is the absolute path of the file.
Download priority for this file. By default, all files have a
priority of `1'. There is no built in scale; the higher the
priority, the better odds a piece from it will be downloaded first.
Setting a file's priority to `1000' while the rest are still at `1'
will likely force the file to complete before any other file is
We do not download files with a priority of zero.
`peers( )'
Returns the list of currently connected peers. The organization of these
peers is not yet final so... don't write anything you don't expect to
break before we hit `v1.0.0'.
`state( )'
Returns `active' if the client is started, `paused' if client is paused,
and `stopped' if the client is currently stopped.
`piece_cache( )'
Pieces which overlap files with zero priority are stored in a part file
which is indexed internally. To save this index (for resume, etc.) store
the values returned by this method and pass it to new( ).
This Module is Lame!
Yeah, I said it.
There are a few things a BitTorrent client must implement (to some
degree) in order to interact with other clients in a modern day swarm.
AnyEvent::BitTorrent is meant to meet that bare minimum but it's based
on Moose or Mouse so you could always subclass it to add more advanced
functionality. Hint, hint!
What is currently supported?
Basic stuff. We can make and handle piece requests. Deal with cancels,
disconnect idle peers, unchoke folks, fast extensions, file download
priorities. Normal... stuff. HTTP trackers.
What will probably be supported in the future?
DHT (which will likely be in a separate dist), IPv6 stuff... I'll get
around to those.
Long term, UDP trackers may be supported.
For a detailed list, see the TODO file included with this distribution.
What will likely never be supported?
We can't have nice things. Protocol encryption, uTP, endgame tricks,
...these will probably never be included in AnyEvent::BitTorrent.
What should I use instead?
If you're reading all of this with a scowl, there are many alternatives
to this module, most of which are sure to be better suited for advanced
users. I suggest (in no particular order):
BitFlu. It's written in Perl but you'll still need to be on a Linux,
*BSD, et al. system to use it.
Net::BitTorrent the future. I *do not* suggest using either the
current stable or unstable versions found on CPAN. The next version is
being worked on and will be based on Reflex.
If you're working on a Perl based client and would like me to link to
it, send a bug report to the tracker listed below.
Subclassing AnyEvent::BitTorrent
If you subclass this module and change the way it functions to that
which in any way proves harmful to individual peers or the swarm at
large, rather than damage AnyEvent::BitTorrent's reputation, override
the peerid attribute. Thanks.
PeerID Specification
AnyEvent::BitTorrent may be identified in a swarm by its peer id. As of
this version, our peer id is in 'Azureus style' with a single digit for
the Major version, two digits for the minor version, and a single
character to indicate stability (stable releases marked with `S',
unstable releases marked with `U'). It looks sorta like:
-AB110S- Stable v1.10.0 relese (typically found on CPAN, tagged in repo)
-AB110U- Unstable v1.10.X release (private builds, early testing, etc.)
Bug Reports
If email is better for you, my address is mentioned below but I would
rather have bugs sent through the issue tracker found at
Please check the ToDo file included with this distribution in case your
bug is already known (...I probably won't file bug reports to myself).
See Also
Net::BitTorrent::Protocol - The package which does all of the wire
protocol level heavy lifting.
Sanko Robinson <> -
License and Legal
Copyright (C) 2011-2012 by Sanko Robinson <>
This program is free software; you can redistribute it and/or modify it
under the terms of The Artistic License 2.0. See the LICENSE file
included with this distribution or notes on the Artistic License 2.0 for
When separated from the distribution, all original POD documentation is
covered by the Creative Commons Attribution-Share Alike 3.0 License. See
the clarification of the CCA-SA3.0.
Neither this module nor the Author is affiliated with BitTorrent, Inc.
Jump to Line
Something went wrong with that request. Please try again.