pull-flood

simplest gossip protocol.

protocol

when creating a new message, send it to all connected peers. when receiving a message, if you have not already seen it, send it to all peers except the one who sent it to you.

example

var Flood = require('pull-flood')

var flood = Flood({
  onMessage: function (msg) {
    console.log('received', msg)
  },
  capacity: 100, //only keep 100 messages in memory
  //too many messages in buffer, dropped this.
  onDrop: function (msg) {
    console.log('dropped:', msg)
  },
  //connected to a peer
  onConnect: function (id) {
    console.log('connected:', id)
  },
  //disconnected from a peer
  onDisconnect: function (id) {
    console.log('disconnected:', id)
  }
})

flood.data //access to raw data

//create a duplex stream to a remote instance. 
var stream = flood.createStream({id: <remote_id>})

duplex stream

This module uses a duplex stream (two way communication) This sort of stream is used in communication protocols to use something with a duplex stream, you connect it both ways:

var net = require('pull-net')
var toPull = require('stream-to-pull-stream')
var PJSON = require('pull-json-doubleline')

//accept duplex streams on the server
net.createServer(function (stream) {
  var id = stream.remoteAddress + ':' + stream.remotePort //or some other way to set an id
  var remote = toPull.duplex(stream)
  pull(
    remote,
    PJSON.parse(),
    flood.createStream({id: id}),
    PJSON.stringify(),
    remote
  )
}).listen(PORT)


//create a duplex stream from a client
var remote = toPull.duplex(net.connect(address, port))
var id = address+':'+port
pull(
  remote,
  PJSON.parse(),
  flood.createStream({id: id}),
  PJSON.stringify(),
  remote
)

api

Flood(opts) => flood

create a pull-flood instance.

flood.append(msg)

append a message to the data. if msg is new, will call opts.onChange and broadcast the change to any peers.

flood.createStream(opts)

returns a duplex stream. to communicate with a remote server, you will need to pass this through an encoding, for example pull-json-doubleline

opts.id is mandatory. it should be set to something unique that identifies the peer, otherwise opts.onConnect calls will not make sense.

flood.data <Array>

an array of messages in the system. read from this value, but do not write!

License

MIT