first commit

.gitignore

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+node_modules

LICENSE

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+The MIT License (MIT)
+
+Copyright (c) 2015 Mathias Buus
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

README.md

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+# discovery-swarm
+
+A network swarm that uses discovery-channel to find peers
+
+```
+npm install discovery-swarm
+```
+
+## Usage
+
+``` js
+var swarm = require('discovery-swarm')
+
+var sw = swarm()
+
+sw.listen(1000)
+sw.add('hello') // a name
+
+sw.on('connection', function (connection) {
+  console.log('found peer')
+})
+```
+
+## API
+
+#### `var sw = swarm()`
+
+Create a new swarm
+
+#### `sw.add(name)`
+
+Join a swarm
+
+#### `sw.remove(name)`
+
+Leave a swarm
+
+#### `sw.peersQueued`
+
+Number of peers discovered but not connected to yet
+
+#### `sw.peersConnecting`
+
+Number of peers we are trying to connect to
+
+#### `sw.peersConnected`
+
+Number of peers we are actively connected to. Same as `sw.connections.length`.
+
+#### `sw.connections`
+
+List of active connections to other peers
+
+#### `sw.on('connection', connection)`
+
+Emitted when you connect to another peer
+
+#### `sw.listen(port)`
+
+Listen on a specific port. Should be called before add
+
+## License
+
+MIT

example.js

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+var swarm = require('./')
+
+var ids = [1,2,3,4,5]
+
+ids.forEach(function (id) {
+  var s = swarm({maxConnections: 2})
+
+  s.listen(10000 + id)
+  s.add(Buffer('hello'))
+
+  s.on('connection', function (connection, type) {
+    console.log(id, 'connect', type)
+  })
+})

index.js

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+var DC = require('discovery-channel')
+var net = require('net')
+try {
+  var utp = require('utp-native')
+} catch {
+  var utp = null
+}
+var connections = require('connections')
+var lpmessage = require('length-prefixed-message')
+var crypto = require('crypto')
+var events = require('events')
+var util = require('util')
+
+var CONNECT_TIMEOUT = 3000
+
+module.exports = Swarm
+
+function Swarm (opts) {
+  if (!(this instanceof Swarm)) return new Swarm(opts)
+  if (!opts) opts = {}
+
+  events.EventEmitter.call(this)
+
+  var self = this
+
+  this._discovery = opts.discovery || DC(opts)
+  this._discovery.on('peer', function (hash, peer) {
+    var peerId = peer.host + ':' + peer.port
+
+    if (self._peersSeen[peerId]) return
+    self._peersSeen[peerId] = true
+    self._peersQueued.push(peer)
+    connectPeer()
+  })
+
+  this._peersQueued = []
+  this._peersSeen = {}
+
+  this._tcpServer = net.createServer(onconnection)
+  this._utpServer = utp && opts.utp && utp.createServer(onconnection)
+  this._outboundConnections = {}
+  this._inboundConnections = {}
+  this._banned = {}
+  this._port = 0
+
+  this.maxConnections = opts.maxConnections || 100
+  this._tcpServer.maxConnections = this.maxConnections
+  if (this._utpServer) this._utpServer.maxConnections = this.maxConnections
+
+  this.id = opts.id || crypto.randomBytes(32)
+  var servers = this._utpServer ? [this._tcpServer, this._utpServer] : [this._tcpServer]
+
+  this.allConnections = connections(servers)
+  this._connections = connections([])
+
+  this.allConnections.on('close', connectPeer)
+
+  this._connections.on('close', function (connection) {
+    delete self._outboundConnections[connection.remoteId]
+    delete self._inboundConnections[connection.remoteId]
+    connectPeer()
+  })
+
+  this._connections.on('connection', function (connection) {
+    var type = self._utpServer && (connection._utp === self._utpServer ? 'utp' : 'tcp')
+    self.emit('connection', connection, type)
+  })
+
+  this.connections = this._connections.sockets
+
+  function connectPeer () {
+    if (self.connections.length >= self.maxConnections) return
+    if (self.allConnections.length >= self.maxConnections) return
+
+    var peer = self._peersQueued.shift()
+    if (!peer) return
+
+    var tcpSocket = net.connect(peer.port, peer.host)
+    var utpSocket = self._utpServer && self._utpServer.connect(peer.port, peer.host)
+    var timeout = setTimeout(ontimeout, CONNECT_TIMEOUT)
+
+    if (utpSocket) {
+      self.allConnections.add(utpSocket)
+      utpSocket.on('connect', onconnect)
+      utpSocket.on('error', onerror)
+    }
+
+    self.allConnections.add(tcpSocket)
+    tcpSocket.on('connect', onconnect)
+    tcpSocket.on('error', onerror)
+
+    function onconnect () {
+      clearTimeout(timeout)
+      var other = this === tcpSocket ? utpSocket : tcpSocket
+      if (other) other.destroy()
+      self.allConnections.add(this)
+      onconnection(this, peer)
+    }
+
+    function onerror (err) {
+      this.destroy()
+    }
+
+    function ontimeout () {
+      tcpSocket.destroy()
+      utpSocket.destroy()
+    }
+  }
+
+  function onconnection (connection, peer) {
+    connection.on('error', function () {
+      connection.destroy()
+    })
+
+    lpmessage.write(connection, self.id)
+    lpmessage.read(connection, function (remoteId) {
+      var idHex = self.id.toString('hex')
+      var remoteIdHex = remoteId.toString('hex')
+
+      if (idHex === remoteIdHex) {
+        if (peer) self.banPeer(peer)
+        connection.destroy()
+        return
+      }
+
+      if (self._inboundConnections[remoteIdHex] || self._outboundConnections[remoteIdHex]) {
+        // TODO: maybe destroy the old one?
+        connection.destroy()
+        return
+      }
+
+      if (peer) {
+        self._outboundConnections[remoteIdHex] = true
+      } else {
+        self._inboundConnections[remoteIdHex] = true
+      }
+
+      connection.peer = peer
+      connection.remoteId = remoteId
+      self._connections.add(connection)
+    })
+  }
+}
+
+util.inherits(Swarm, events.EventEmitter)
+
+Swarm.prototype.__defineGetter__('peersQueued', function () {
+  return this._peersQueued.length
+})
+
+Swarm.prototype.__defineGetter__('peersConnected', function () {
+  return this.connections.length
+})
+
+Swarm.prototype.__defineGetter__('peersConnecting', function () {
+  return this.allConnections.length - this.connections.length
+})
+
+Swarm.prototype.banPeer = function (peer) {
+  this._banned[peer.host + ':' + peer.port] = true
+}
+
+Swarm.prototype.addPeer = function (peer) {
+  this._peersQueued.push(peer)
+}
+
+Swarm.prototype.add = function (hash) {
+  this._discovery.add(hash, this._port)
+}
+
+Swarm.prototype.remove = function (hash) {
+  this._discovery.remove(hash, this._port)
+}
+
+Swarm.prototype.listen = function (port) {
+  this._port = port
+  this._tcpServer.listen(port)
+  if (this._utpServer) this._utpServer.listen(port)
+}

package.json

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+{
+  "name": "discovery-swarm",
+  "version": "0.0.0",
+  "description": "A network swarm that uses discovery-channel to find peers",
+  "main": "index.js",
+  "dependencies": {
+    "discovery-channel": "^2.1.0"
+  },
+  "devDependencies": {},
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/mafintosh/discovery-swarm.git"
+  },
+  "author": "Mathias Buus (@mafintosh)",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/mafintosh/discovery-swarm/issues"
+  },
+  "homepage": "https://github.com/mafintosh/discovery-swarm"
+}