STorrent

STorrent is a BitTorrent client written almost entirely in Akka.

STorrent heavily leverages Akka's reactive IO features to provide a (hopefully) simple set of abstractions around establishing connections with peers, reading/write bytestreams and parsing those bytestreams into BitTorrent's message model.

Inspiration

STorrent was heavily inspired by Ttorrent which I initially attempted to port to Akka but then decided to start entirely from scratch after taking the Coursera Reactive Programming course.

Testing

STorrent has been tested throughout, leveraging akka-testkit and scalatest to test the expected inputs/outputs, parent/child communication and actor termination, as well as regular specs for non actor classes.

If you contribute please be sure to add plenty of tests.

Examples

Examples are placed in the io.github.oxlade39.storrent.example package

Distilled:

val sys = ActorSystem("Example")
// this will create and start an actor heirarchy to download the given torrent using default values
val download = sys.actorOf(StorrentDownload.props("examples" / "ubuntu-13.10-desktop-amd64.iso.torrent"), "ubuntu")

Ubuntu download example

io.github.oxlade39.storrent.example.Example demonstrates one example usage of STorrent and can be used to successfully download Ubuntu

Unfinished

STorrent is not finished! For example serving pieces to connected peers is not implemented at all, in other words only downloads are currently supported.

I'm working on fixing that, you can help too.

Code review

This is my first attempt at developing anything significant in Akka, following on from the Coursera Reactive Programming course. I'm keen to improve my Akka and Scala so constructive criticism is welcomed.

The remaining work will be tracked in the issues section, the focus on working toward a 1.0 release which will aim to be a minimum feature working BitTorrent client.

Implementation

Notable implementation areas:

io.github.oxlade39.storrent.core

• Torrent The torrent file model
• BencodeParser implementation of Bencode parsing
• BValue case classes representing the different Bencoded types

io.github.oxlade39.storrent.example

• Example An example of using STorrent to download Ubuntu

There is currently no notification of final completion but this shouldn't be hard to add...

io.github.oxlade39.storrent.peer

io.github.oxlade39.storrent.persistence

Folder and single File persistence, using java.nio

io.github.oxlade39.storrent.piece

• Downloader2 Actor currently responsible for managing and co-ordinating child actors which request and download the individual pieces and blocks. It currently uses a work pulling pattern to queue the available work (pieces from peers) and allow workers to request the next download task (piece from peer) to work on.

Licence

Copyright 2014 Dan Oxlade

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.