bittorrent client

requirements: bencode bitstring

testing against deluge and opentracker on a linode instance

Strategies: Peer can set each torrent to downloading, seeding, or both torrent.seeding = True, torrent.downloading = True Torrents Have Behaviors: Behaviors can be functions that get called a lot, which maintain state. They needn't be methods. On every read/write event for instance, and perhaps also on a timer

Reactor needs timer events Torrent behaviors get called on timer events

peer.send_msg needs to take care of housekeeping for these messages individual messages need to time out, this housekeeping needs to happen even if now

recently done

• Maintain whether connection should be kept open, and keep it open if so
• actually check hashes - so figure out when pieces are done
• file access instead of in-memory file construction
• throw away data in memory after write (need to use representation other than a byte array
• multiple file construction
• if peer dies, return all pending requests
• look at the problems we were having with high pipeline number and lower timed out request time
• factor things out enough that Twisted could be used as a core put message buffer in a separate object, write recv_msg so no read/write events in peer/client objects
• setup better logging
• Use more memory-efficient bitmaps (SBA)

Soon todo

• endgame ask-many and cancel messages
• close connections with peers that say they have everything, or aren't interested
• Don't ask if they don't have the piece
• make sure being choked / being unchoked works ok
• correctly not be interested when peer has nothing we want - read spec to make sure implement with torrent instructing peers in strategies
• Read about and play with request size - presumably piece size is a max spec: >2^17 not allowed, generally 2^15 or 14 unless end of file
• loading of incomplete files so DLs can be resumed either write metadata to disk or guess via runs of 0 bytes
• strategy for torrent choosing peers, keep records of which peers worked, keep asking tracker for new peers periodically
• profile to see where cpu is going

Later todo

• write queries for status for UI to use
• use packages instead of just modules
• Figure out which peers to get which file pieces from (random is reasonable acc. to spec)
• play with reactor timeouts
• game theory algorithms - karma
• change announce params, update more than once
• Can requests spill across pieces?
• profile to see if send operations are blocking (consider sending less data per)
• Play with pipelineing for max DL speed
• writing testing scripts
• write tests for bittorrent logic - fake messages so no network io
• use twisted
• build a query system or other output method for a gui
• Build a frontend visualization of data - urwid or html+js