Hail

Hail is a modern, experimental BitTorrent client written in Go. It implements core BitTorrent protocol features, supports magnet links, multi-file torrents, and advanced extensions for robust peer-to-peer file sharing.

---

Features

• Core BitTorrent Protocol: Implements the core protocol for peer discovery, piece exchange, and file downloading.
• Magnet Link Support: Download torrents using magnet URIs—no need for .torrent files.
• Multi-file Torrents: Handles torrents containing multiple files and directories.
• Files List Parsing: Correctly parses and downloads all files listed in a torrent.
• Multitracker Metadata Extension: Supports torrents with multiple trackers for improved peer discovery.
• UDP Trackers: Communicates with trackers over UDP for faster and more efficient peer discovery.
• Extension Protocols:
  • Metadata Exchange: Supports the extension for peers to send metadata files (BEP 9), enabling magnet link downloads without a .torrent file.
• Leeching Only: Currently, Hail supports downloading (leeching) only. Seeding (uploading to others) is planned for future releases.

---

Usage

Installation

Clone the repository and build the project:

git clone https://github.com/MlkMahmud/hail.git && cd hail && make

Command-Line Interface

hail [--debug] download --torrent <torrent-file-or-magnet-link-or-http-url> --output-dir <destination-directory>

Flags

• --torrent, -t
  Path to a .torrent file, a magnet link, or a HTTP URL that resolves to a .torrent file (required).
• --output-dir, -o
  Destination directory for downloaded files (required).
• --debug, -d
  Enable debug logging output for troubleshooting and development (optional).

---

Examples

Downloading with a .torrent file

./hail download --torrent ./ubuntu.torrent --output-dir ~/Downloads

Downloading with a HTTP URL

./hail download --torrent "https://cdimage.debian.org/debian-cd/current/amd64/bt-dvd/debian-12.11.0-amd64-DVD-1.iso.torrent" --output-dir ~/Downloads

Downloading with a magnet link

./hail download --torrent "magnet:?xt=urn:btih:..." --output-dir ~/Downloads

Enabling Debug Logging

./hail --debug download --torrent ./ubuntu.torrent --output-dir ~/Downloads

---

Roadmap

• Leeching (downloading) support
• Seeding (uploading) support
• DHT (Distributed Hash Table) support
• Improved error handling and peer management
• Web UI

---

License

MIT License

---

Hail is a work in progress. Contributions and feedback are welcome!