This repository implements BitTorrent-related packages and command-line utilities in Go. The emphasis is on use as a library from other projects. It's been used 24/7 in production by a downstream, private service since late 2014.

There is support for protocol encryption, DHT, PEX, uTP, and various extensions. See the package documentation for a more complete list. There are several data storage backends provided: blob, file, and mmap, and you can write your own, such as to store data on S3, or in a database. You can use the provided binaries in ./cmd, or use torrent as a library for your own applications.

Many of the sub-packages can be used for other purposes: dht, bencode, and tracker, in particular.

Install the library package with go get github.com/anacrolix/torrent, or the provided cmds with go get github.com/anacrolix/torrent/cmd/....

There is a small example in the package documentation.

• Go Peerflix
• Cloud Torrent
• Android Torrent Client
• Android libtorrent

There's a branch called mobile that supports binding to torrent with the gomobile tool. It has some API changes as required by gomobile. Checkout the mobile branch, and bind as usual.

Here I'll describe what some of the provided commands in ./cmd do.

Note that the godo command which is invoked in the following examples builds and executes a Go import path, like go run. It's easier to use this convention than to spell out the install/invoke cycle for every single example.

Downloads torrents from the command-line. This first example does not use godo.

$ go get github.com/anacrolix/torrent/cmd/torrent
# Now 'torrent' should be in $GOPATH/bin, which should be in $PATH.
$ torrent 'magnet:?xt=urn:btih:KRWPCX3SJUM4IMM4YF5RPHL6ANPYTQPU'
ubuntu-14.04.2-desktop-amd64.iso [===================================================================>]  99% downloading (1.0 GB/1.0 GB)
2015/04/01 02:08:20 main.go:137: downloaded ALL the torrents
$ md5sum ubuntu-14.04.2-desktop-amd64.iso
1b305d585b1918f297164add46784116  ubuntu-14.04.2-desktop-amd64.iso
$ echo such amaze
wow

torrentfs mounts a FUSE filesystem at -mountDir. The contents are the torrents described by the torrent files and magnet links at -torrentPath. Data for read requests is fetched only as required from the torrent network, and stored at -downloadDir.

$ mkdir mnt torrents
$ godo github.com/anacrolix/torrent/cmd/torrentfs -mountDir mnt -torrentPath torrents &
$ cd torrents
$ wget http://releases.ubuntu.com/14.04.2/ubuntu-14.04.2-desktop-amd64.iso.torrent
$ cd ..
$ ls mnt
ubuntu-14.04.2-desktop-amd64.iso
$ pv mnt/ubuntu-14.04.2-desktop-amd64.iso | md5sum
996MB 0:04:40 [3.55MB/s] [========================================>] 100%
1b305d585b1918f297164add46784116  -

Creates a magnet link from a torrent file. Note the extracted trackers, display name, and info hash.

$ godo github.com/anacrolix/torrent/cmd/torrent-magnet < ubuntu-14.04.2-desktop-amd64.iso.torrent
magnet:?xt=urn:btih:546cf15f724d19c4319cc17b179d7e035f89c1f4&dn=ubuntu-14.04.2-desktop-amd64.iso&tr=http%3A%2F%2Ftorrent.ubuntu.com%3A6969%2Fannounce&tr=http%3A%2F%2Fipv6.torrent.ubuntu.com%3A6969%2Fannounce

Pings DHT nodes with the given network addresses.

$ godo ./cmd/dht-ping router.bittorrent.com:6881 router.utorrent.com:6881
2015/04/01 17:21:23 main.go:33: dht server on [::]:60058
32f54e697351ff4aec29cdbaabf2fbe3467cc267 (router.bittorrent.com:6881): 648.218621ms
ebff36697351ff4aec29cdbaabf2fbe3467cc267 (router.utorrent.com:6881): 873.864706ms
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