rqbit - bittorrent client in Rust

rqbit is a bittorrent client written in Rust.

Motivation

First of all, I love Rust. The project was created purely for the fun of the process of writing code in Rust.

I was not satisfied with my regular bittorrent client, and was wondering how much work would it be to create a new one from scratch.

Got it to the point where it downloads torrents reliably and pretty fast, and I was using for a few months myself. It works good enough for me, and at the moment of writing this I'm not planning to extend it further.

So in short, it's not "feature complete", but rather "good enough for my use-cases".

Open sourced it just in case anyone might find it useful and/or wants to contribute.

Installation

There are pre-built binaries in releases. If someone wants to put rqbit into e.g. homebrew, PRs welcome :)

Build

Just a regular Rust binary build process.

cargo build --release

Usage quick start

Optional - start the server

Assuming you are downloading to ~/Downloads.

rqbit server start ~/Downloads

Download torrents

Assuming you are downloading to ~/Downloads. If the server is already started, -o ~/Downloads can be omitted.

rqbit download -o ~/Downloads 'magnet:?....' [https?://url/to/.torrent] [/path/to/local/file.torrent]

Useful options

-v

Increase verbosity. Possible values: trace, debug, info, warn, error.

--list

Will print the contents of the torrent file or the magnet link.

--overwrite

If you want to resume downloading a file that already exists, you'll need to add this option.

--peer-connect-timeout=10s

This will increase the default peer connect timeout. The default one is 2 seconds, and it's sometimes not enough.

-r / --filename-re

Use a regex here to select files by their names.

Features and missing features

Some supported features

Sequential downloading (the default and only option)
Resume downloading file(s) if they already exist on disk
Selective downloading using a regular expression for filename
DHT support. Allows magnet links to work, and makes more peers available.
HTTP API

Code features

Serde-based bencode serializer/deserializer
Custom code for binary protocol serialization/deserialization. And for everything else too :)
Supports several SHA1 implementations, as this seems to be the biggest performance bottleneck. Default is openssl as it's the fastest in my benchmarks.
In theory, the libraries that rqbit is made of are re-usable.
No unsafe

Bugs, missing features and other caveats

Below points are all easily fixable, PRs welcome.

Doesn't survive switching networks, i.e. doesn't reconnect to a peer once the TCP connection is closed.
Only supports BitTorrent V1 over TCP
As this was created for personal needs, and for educational purposes, documentation, commit message quality etc. leave a lot to be desired.

Code organization

crates/rqbit - main binary
crates/librqbit - main library
crates/librqbit-core - torrent utils
crates/bencode - bencode serializing/deserializing
crates/buffers - wrappers around binary buffers
crates/clone_to_owned - a trait to make something owned
crates/sha1w - wrappers around sha1 libraries
crates/peer_binary_protocol - the protocol to talk to peers
crates/dht - Distributed Hash Table implementation

HTTP API

By default it listens on http://127.0.0.1:3030.

curl -s 'http://127.0.0.1:3030/'

{
    "apis": {
        "GET /": "list all available APIs",
        "GET /dht/stats": "DHT stats",
        "GET /dht/table": "DHT routing table",
        "GET /torrents": "List torrents (default torrent is 0)",
        "GET /torrents/{index}": "Torrent details",
        "GET /torrents/{index}/haves": "The bitfield of have pieces",
        "GET /torrents/{index}/stats": "Torrent stats",
        "POST /torrents/": "Add a torrent here. magnet: or http:// or a local file."
    }
}

Add torrent through HTTP API

curl -d 'magnet:?...' http://127.0.0.1:3030/torrents

curl -d 'http://.../file.torrent' http://127.0.0.1:3030/torrents

curl -d '/some/local/file.torrent' http://127.0.0.1:3030/torrents

Supported query parameters, all optional:

overwrite=true|false
only_files_regex - the regular expression string to match filenames
output_folder - the folder to download to. If not specified, defaults to the one that rqbit server started with
list_only=true|false - if you want to just list the files in the torrent instead of downloading

ikatson/rqbit

ikatson

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