esmakov/bittorrent-client

A (mostly) from scratch BitTorrent client. WIP

A minimal bittorrent client made purely as a learning project, USE AT YOUR OWN RISK.

The mktorrent package is required to build test code.

Usage

go run main <add>|<info>|<tree> <path/to/file.torrent>

• The following commands are supported:
  • add: Add a new torrent and start downloading.
  • info: Display information about the torrent (total size, # of files, etc.)
  • tree: Display the torrent file structure.
• <path/to/file.torrent> is the required path to a .torrent file.

Features

• Parses bencoded .torrent files and tracker responses
• Supports bencoding structured data for serialization
• Parses peer message format
• Downloads single or multi-file torrents
• Checks existing data on disk and picks up from where you left off

Supported BEPs (BitTorrent Enhancement Proposals)

• 3: Basic BitTorrent protocol (in progress)
• 23: Tracker Returns Compact Peer Lists

TODOs

• Send 'have' messages to all peers when a piece is downloaded
• Run in background
• Blacklist misbehaving peers
• Specify destination directory
• More subcommands: remove, pause/resume
• More interesting bitmask visualization
• Use already-written bencode package to generate .torrent files (instead of pobrn/mktorrent)

Optimizations

• Better piece download strategies (rarest first)
• Better peer selection strategies (optimistic unchoking)

Protocol

• Support the dictionary model for tracker responses listing available peers

Extensions

• DHT
• Peer Exchange