/**
* WebSocket transport. Needed because browsers can't handle TCP sockets
* so we use separate WebSocket server to proxy messages into TCP data
* packets. Available for both Node.js and Browser platforms.
* **NOTE**: `WsTransport` is exported as a module.
* @example var WsTransport = require("bitmessage/lib/net/ws");
* @module bitmessage/net/ws
*/
"use strict";
var objectAssign = Object.assign || require("object-assign");
var inherits = require("inherits");
var WebSocket = require("ws"); // jshint ignore:line
var assert = require("../_util").assert;
var PPromise = require("../platform").Promise;
var structs = require("../structs");
var messages = require("../messages");
var BaseTransport = require("./base");
var WebSocketServer = WebSocket.Server;
var getmsg = BaseTransport._getmsg;
var unmap = BaseTransport._unmap;
/**
* WebSocket transport class. Implements [base transport
* interface]{@link module:bitmessage/net/base.BaseTransport}.
* @param {Object=} opts - Transport options
* @param {Array} opts.seeds - Bootstrap nodes (none by default)
* @param {Object} opts.services -
* [Service features]{@link module:bitmessage/structs.ServicesBitfield}
* provided by this node (`NODE_NETWORK` by default)
* @param {(Array|string|Buffer)} opts.userAgent -
* [User agent]{@link module:bitmessage/user-agent} of this node
* (bitmessage's by default)
* @param {number[]} opts.streamNumbers - Streams accepted by this node
* (1 by default)
* @param {number} opts.port - Incoming port of this node (8444 by
* default)
* @constructor
* @static
*/
function WsTransport(opts) {
WsTransport.super_.call(this);
objectAssign(this, opts);
this.seeds = this.seeds || [];
}
inherits(WsTransport, BaseTransport);
function getfrom(client) {
return unmap(client._socket.remoteAddress) + ":" + client._socket.remotePort;
}
WsTransport.prototype._sendVersion = function() {
return this.send(messages.version.encode({
services: this.services,
userAgent: this.userAgent,
streamNumbers: this.streamNumbers,
port: this.port,
remoteHost: this._client._socket.remoteAddress,
remotePort: this._client._socket.remotePort,
}));
};
WsTransport.prototype._handleTimeout = function() {
var client = this._client;
// TODO(Kagami): We may also want to close connection if it wasn't
// established within minute.
client._socket.setTimeout(20000);
client._socket.on("timeout", function() {
client.close();
});
this.on("established", function() {
// Raise timeout up to 10 minutes per spec.
// TODO(Kagami): Send ping frame every 5 minutes as PyBitmessage.
client._socket.setTimeout(600000);
});
};
WsTransport.prototype._setupClient = function(client, accepted) {
var self = this;
self._client = client;
var verackSent = false;
var verackReceived = false;
var established = false;
client.on("open", function() {
// NOTE(Kagami): This handler shouldn't be called at all for
// accepted sockets but let's be sure.
if (!accepted) {
// NOTE(Kagami): We may set timeout only after connection was
// opened because socket may not yet be available when
// `_setupClient` is called.
self._handleTimeout();
self.emit("open");
self._sendVersion();
}
});
client.on("message", function(data, flags) {
var decoded;
if (!flags.binary) {
// TODO(Kagami): Send `error` message and ban node for some time
// if there were too many errors?
return self.emit("warning", new Error(
"Peer " + getfrom(client) + " sent non-binary data"
));
}
try {
decoded = structs.message.decode(data);
} catch (err) {
return self.emit("warning", new Error(
"Message decoding error from " + getfrom(client) + ": " + err
));
}
self.emit("message", decoded.command, decoded.payload, decoded);
});
// High-level message processing.
self.on("message", function(command) {
if (!established) {
// TODO: Process version data.
// TODO: Disconnect if proto version < 3.
if (command === "version") {
if (verackSent) {
return;
}
self.send("verack");
verackSent = true;
if (accepted) {
self._sendVersion();
} else if (verackReceived) {
established = true;
self.emit("established");
}
} else if (command === "verack") {
verackReceived = true;
if (verackSent) {
established = true;
self.emit("established");
}
}
}
});
client.on("error", function(err) {
self.emit("error", err);
});
client.on("close", function() {
self.emit("close");
delete self._client;
});
};
WsTransport.prototype.bootstrap = function() {
return PPromise.resolve([].concat(this.seeds));
};
/**
* Connect to a WebSocket node. Connection arguments are the same as for
* [WebSocket](https://developer.mozilla.org/en-US/docs/Web/API/WebSocket).
*/
WsTransport.prototype.connect = function(address, protocols, options) {
assert(!this._client, "Already connected");
assert(!this._server, "Already listening");
// `new` doesn't work with `apply`, so passing all possible arguments
// manually.
this._setupClient(new WebSocket(address, protocols, options));
};
/**
* Listen for incoming WebSocket connections. Listen arguments are the
* same as for
* [WebSocketServer](https://github.com/websockets/ws#server-example).
* Available only for Node platform.
*/
WsTransport.prototype.listen = function(options, callback) {
assert(!this._client, "Already connected");
assert(!this._server, "Already listening");
var self = this;
var server = self._server = new WebSocketServer(options, callback);
// TODO(Kagami): We may want to specify some limits for number of
// connected users.
server.on("connection", function(client) {
var addr = client._socket.remoteAddress;
var port = client._remotePort;
var i;
// NOTE(Kagami): O(n) search because `clients` array is already
// provided by `ws` library. We may want to optmize it though and
// also disable `clientTracking` option.
for (i = 0; i < server.clients.length; i++) {
if (server.clients[i] !== client &&
server.clients[i]._socket.remoteAddress === addr) {
// NOTE(Kagami): Doesn't allow more than one connection per IP.
// This may obstruct people behind NAT but we copy
// PyBitmessage's behavior here.
client.close();
return self.emit("warning", new Error(
unmap(addr) + " was tried to create second connection"
));
}
}
var transport = new self.constructor(self);
var accepted = true;
transport._setupClient(client, accepted);
transport._handleTimeout();
self.emit("connection", transport, unmap(addr), port);
// Emit "open" manually because it won't be fired for already opened
// socket.
transport.emit("open");
});
server.on("error", function(err) {
self.emit("error", err);
});
};
WsTransport.prototype.send = function() {
if (this._client) {
// TODO(Kagami): `mask: true` doesn't work with Chromium 40. File a
// bug to ws bugtracker.
this._client.send(getmsg(arguments), {binary: true});
} else {
throw new Error("Not connected");
}
};
WsTransport.prototype.broadcast = function() {
var data = getmsg(arguments);
if (this._server) {
this._server.clients.forEach(function(client) {
client.send(data, {binary: true});
});
} else {
throw new Error("Not listening");
}
};
WsTransport.prototype.close = function() {
if (this._client) {
this._client.close();
} else if (this._server) {
// `ws` server terminates immediately without any events.
this._server.close();
this.emit("close");
delete this._server;
}
};
module.exports = WsTransport;