#How to open a torrent in bittorrent how to#
#How to open a torrent in bittorrent utorrent#

If you are using python, note that there is a good bencode 3rd party library that can do the encoding/decoding for you.

Again, the spec is helpful for explaining the different tags and structure. Note that the structure is slightly different for single file vs multiple file torrents. In particular, you will at least need the ‘announce’ url and ‘info’ dictionary, and within the info dictionary you will need the ‘piece length’, ‘name’, ‘pieces’ (hash list), and ‘paths’ and ‘lengths’ of all individual files. You’ll likely want to decode the torrent file and save much of the information that is stored there for later use. This is good to understand and be able to read.

There is an explanation of bencoding in the unofficial spec here. Bencoding is an encoding that translates a complex set of embedded dictionaries, lists, strings, and integers into a single string. See how it starts with a ‘d’ and ends with an ‘e’ and has plenty of funny ‘#:word’ sections? That’s called bencoding. Instead it is a metafile containing information that you will need in order to download the real file. This is NOT the actual file you want to download. You’ll notice that there is not really a whole lot here. Wireshark is cool tool to learn about other network traffic as well, and I encourage you to play around with it. This information can be helpful in both understanding the spec and also for comparison later when you run into message-passing bugs. When your torrent is finished downloading, you can stop wireshark and save your session for later analysis. Filter the Wireshark results with the keyword ‘bittorrent’ and you can see just the bittorrent messages. While your torrent downloads, you can watch the packets and messages being sent to/from peers with Wireshark. torrent file in your bittorrent client (on the clients mentioned above, go to File, Open Torrent, and select your. Launch a Wireshark session and open your. Mininova is a good place to look for legal (I think) torrent files. These can be found in many places online.

#How to open a torrent in bittorrent utorrent#

I also recommend downloading an already-written bittorrent client (I can recommend utorrent or the official bittorrent client – both from the same code base).

Understanding the spec will make this project far easier for you going forward. There is an official spec as well, but it is vague and much less helpful.

Read the unofficial specification here.

This post will be broken into two parts, of which this is the first.

#How to open a torrent in bittorrent how to#

This post will cover a general outline of how to approach the project, with a focus on downloading torrent files and a bias toward python. I spent the first few weeks of Hacker School writing my own client utilizing the Bittorrent Protocol, and thought I would share some of the things that I learned on the way.