Mathias Buus @mafintosh

javascript and bittorrent

... and MAD SCIENCE!

how does bittorrent work?

when people think of bittorent they usually think:

盗版!

bittorent is way more than this

normal way of fetching content online

nice and simple

what happens when 1,000,000 clients arrive

what if clients just share data between each other instead?

THIS IS P2P

But can we trust incoming data?

split the file into pieces ~(512kb - 10mb) and hash each of them

[
  hash(piece_1),
  hash(piece_2),
  ...
  hash(piece_N)
]

If we get piece #1 we verify it using hash #1

we could store the list of hashes (torrent file) on a trusted server

RECURSION TO THE RESCUE!

magnet_link = hash([
  hash(piece_1),
  hash(piece_2),
  ...
  hash(piece_N)
])

use magnet link to verify the hashes

... but how do we find peers that share our file?

DISTRIBUTED
HASH
TABLE

every peer joins the dht

{
  magnet_link_1: 'my-ip:my-port',
  magnet_link_2: 'my-ip:my-port',
  ...
}
  

~10,000,000 nodes at any time (source)

this is basically how bittorrent downloads data

PRETTY SIMPLE

bittorrent can distribute A LOT of content

we want to access ALL this content instantly

how can we make bittorrent stream?

streaming bittorrent means fetching pieces based on demand

concurrent fetch of most critical pieces

I IMPLEMENTED THIS

torrent-stream is a node module that does this

    var engine = torrentStream(torrentFile)
    var file = engine.files[0]
    var stream = file.createReadStream({
      start: 0,
      end: 1000
    })
  

streaming content is a
billion dollar industry

netflix uses ~1/3 of internet traffic during peak hours (source)

1/3!

what if we could stream video content using P2P?

peerflix streams video to vlc

Mathias, show demo of peerflix

where normal streaming decreases quality under load we could increase it

the more people who watch the video the better it runs

this is not a gimmick

MAD SCIENCE TIME

stream any content

all of wikipedia is on bittorrent

peerwiki browses wikipedia using bittorrent

Mathias, show demo of peerwiki

linux is on bittorrent

what if virtual box understood streams?

what if virtual box understood streams?

what if virtual box did not change a thing?

torrent-mount mounts a torrent as a file system

Mathias, show demo of torrent-mount

谢谢!
mathiasbuus@gmail.com
github.com/mafintosh

webtorrent
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scuttlebutt
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