# torrent

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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.

## Installation

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

## Library example

There is a small example in the [package documentation](https://godoc.org/github.com/anacrolix/torrent).

## Commands

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

Note that [`godo`](https://github.com/anacrolix/godo) that I invoke in the following examples is a command that 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.

### torrent

Downloads torrents from the command-line.

	$ go get github.com/anacrolix/torrent/cmd/torrent
	$ torrent 'magnet:?xt=urn:btih:KRWPCX3SJUM4IMM4YF5RPHL6ANPYTQPU'
    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

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  -

### torrent-magnet

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

### dht-ping

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
    2/2 responses (100.000000%)