Net::BitTorrent::PeerPacket - Parse/Build Peer Packets from BitTorrent
# Encode a packet my $binary_packet = bt_build_packet($key1, $value1, $key2, $value2); # Decode a packet my $parsed_packet = bt_parse_packet($binary_data);
Net::BitTorrent::PeerPacket handles parsing and building binary data shared between BitTorrent peers. The module optinally exports a single subroutine for building packets and another for parsing packets, as well as, a constant for each packet type defined by BitTorrent.
Net::BitTorrent::PeerPacket
There are nine primary types of packets that are shared between peers on a BitTorrent network. The following constants are how the type of packet being build/parsed are represented within this module.
This subroutine is responsible for building all types of BitTorrent packets. The arguments are passed into the subroutine as a list of key-value pairs. The resultant packet is sent back as a scalar.
Depending on the requested packet type, the required arguments vary. One argument that is common to all calls is the bt_code. The bt_code maps to a BT_ constant exported by this module and determines the type of packet that will be built.
What follows is a list of the different BT codes and the details of calling this subroutine with those codes.
Passing the BT_CHOKE code causes a choke packet to be generated. This type of packet requires no additional data and therefore no additional arguments.
Passing the BT_UNCHOKE code causes an unchoke packet to be generated. This type of packet requires no additional data and therefore no additional arguments.
Passing the BT_INTERESTED code causes an interested packet to be generated. This type of packet requires no additional data and therefore no additional arguments.
Passing the BT_UNINTERESTED code causes an uninterested packet to be generated. This type of packet requires no additional data and therefore no additional arguments.
Passing the BT_HAVE code causes a have packet to be generated. This type of packet requires a piece index in addition to the BT code.
The piece index is the zero-based numeric index of a piece within a torrent.
Passing the BT_BITFIELD code causes a bit field packet to be generated. This type of packet requires the bit field be specified in addition to the BT code.
The bit field is passed in as a reference to a scalar. The scalar contains binary data representing the pieces that are present and missing.
Passing the BT_REQUEST code causes a request packet to be generated. This type of packet requires the piece index along with block offset and size in addition to the BT code.
The block offset is the zero-based byte offset of the requested data within the specified piece.
The block size is the size of the data requested. Be sure not to set this value too large, as some clients will end your connection if your request is too big.
Passing the BT_PIECE code causes a piece packet to be generated. This type of packet requires the piece index along with block offset and the data to be transfered in addition to the BT code.
The data reference is a reference to a scalar containing the data at the specified block offset within the specified piece.
Passing the BT_CANCEL code causes a cancel packet to be generated. This type of packet requires the piece index along with block offset and size in addition to the BT code.
This subroutine is responsible for parsing all types of BitTorrent packets. It accepts a single argument, which is a reference to a scalar that contains the raw packet data. It returns a hash reference containing the parsed data.
Depending on the packet type, the keys in the returned hash vary. One key that is common to all packets is the bt_code. The bt_code maps to a BT_ constant exported by this module and reveals the type of packet that was parsed.
What follows is a list of the different BT codes that might be returned and the additional keys that will be packaged with each code.
The resultant hash from a choke packet will only contain the 'bt_code' key.
The resultant hash from an unchoke packet will only contain the 'bt_code' key.
The resultant hash from an interested packet will only contain the 'bt_code' key.
The resultant hash from an uninterested packet will only contain the 'bt_code' key.
The resultant hash from a have packet will only contain the 'bt_code' key and the following additional keys.
The resultant hash from a bit field packet will only contain the 'bt_code' key and the following additional keys.
The resultant hash from a request packet will only contain the 'bt_code' key and the following additional keys.
The resultant hash from a piece packet will only contain the 'bt_code' key and the following additional keys.
The resultant hash from a cancel packet will only contain the 'bt_code' key and the following additional keys.
perl Build.PL ./Build ./Build test ./Build install
Josh McAdams <joshua dot mcadams at gmail dot com>
To install Net::BitTorrent::PeerPacket, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Net::BitTorrent::PeerPacket
CPAN shell
perl -MCPAN -e shell install Net::BitTorrent::PeerPacket
For more information on module installation, please visit the detailed CPAN module installation guide.