NAME
AnyEvent::BitTorrent - Yet Another BitTorrent Client Module
Synopsis
use AnyEvent::BitTorrent;
my $client = AnyEvent::BitTorrent->new( path => 'some.torrent' );
AE::cv->recv;
Description
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
Lame!"
Methods
The API, much like the module itself, is simple.
`new( ... )'
This constructor understands the following arguments:
`path'
This is the only required parameter. It's the path to a valid
.torrent file.
`basedir'
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.
`port'
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
randomly.
`on_hash_fail'
This is a subroutine called whenever a piece fails to pass
hashcheck. The callback is handed the piece's index.
`on_hash_pass'
This is a subroutine called whenever a piece passes its
hashcheck. The callback is handed the piece's index.
`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.
In addition to these, there are several informational methods which do
not trigger or modify any activity:
`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 suggested name to 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 we still plan on downloading.
`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 zero.
`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.
Currently, this is just `~ $client->bitfield( )' but if your
subclass has file based priorities, you could only 'want' the pieces
which lie inside of the files you want.
`files( )'
Returns a list of hash references with the following keys:
`length'
Which is the size of file in bytes.
`path'
Which is the absolute path of the file.
`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'.
Anything you find by skimming the source is likely not ready for public
use and will be subject to change before `v1.0.0'.
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. Normal... stuff. HTTP trackers are
supported but do not perform according to spec yet.
What will probably be supported in the future?
DHT (which will likely be in a separate dist), fast extensions,
multi-tracker extensions, IPv6 stuff, file download priorities... 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 ...in 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
TODO
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 looks sorta like:
-AB0110-XXXXXXXXXXXX
Where `0110' are the Major (`01') and minor (`10') version numbers and
the `X's are random filler.
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
http://github.com/sanko/anyevent-bittorrent/issues.
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.
Author
Sanko Robinson <sanko@cpan.org> - http://sankorobinson.com/
CPAN ID: SANKO
License and Legal
Copyright (C) 2011-2012 by Sanko Robinson <sanko@cpan.org>
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
clarification.
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.