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/************************************************************************
* Copyright 2010-2015 Brian McKelvey.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
***********************************************************************/
var extend = require('./utils').extend;
var utils = require('./utils');
var util = require('util');
var EventEmitter = require('events').EventEmitter;
var WebSocketRequest = require('./websocket_request');
var WebSocketServer = function WebSocketServer(config) {
// Superclass Constructor
EventEmitter.call(this);
this._handlers = {
upgrade: this.handleUpgrade.bind(this),
requestAccepted: this.handleRequestAccepted.bind(this),
requestResolved: this.handleRequestResolved.bind(this)
};
this.connections = [];
this.pendingRequests = [];
if (config) {
this.mount(config);
}
};
util.inherits(WebSocketServer, EventEmitter);
WebSocketServer.prototype.mount = function(config) {
this.config = {
// The http server instance to attach to. Required.
httpServer: null,
// 64KiB max frame size.
maxReceivedFrameSize: 0x10000,
// 1MiB max message size, only applicable if
// assembleFragments is true
maxReceivedMessageSize: 0x100000,
// Outgoing messages larger than fragmentationThreshold will be
// split into multiple fragments.
fragmentOutgoingMessages: true,
// Outgoing frames are fragmented if they exceed this threshold.
// Default is 16KiB
fragmentationThreshold: 0x4000,
// If true, fragmented messages will be automatically assembled
// and the full message will be emitted via a 'message' event.
// If false, each frame will be emitted via a 'frame' event and
// the application will be responsible for aggregating multiple
// fragmented frames. Single-frame messages will emit a 'message'
// event in addition to the 'frame' event.
// Most users will want to leave this set to 'true'
assembleFragments: true,
// If this is true, websocket connections will be accepted
// regardless of the path and protocol specified by the client.
// The protocol accepted will be the first that was requested
// by the client. Clients from any origin will be accepted.
// This should only be used in the simplest of cases. You should
// probably leave this set to 'false' and inspect the request
// object to make sure it's acceptable before accepting it.
autoAcceptConnections: false,
// Whether or not the X-Forwarded-For header should be respected.
// It's important to set this to 'true' when accepting connections
// from untrusted clients, as a malicious client could spoof its
// IP address by simply setting this header. It's meant to be added
// by a trusted proxy or other intermediary within your own
// infrastructure.
// See: http://en.wikipedia.org/wiki/X-Forwarded-For
ignoreXForwardedFor: false,
// The Nagle Algorithm makes more efficient use of network resources
// by introducing a small delay before sending small packets so that
// multiple messages can be batched together before going onto the
// wire. This however comes at the cost of latency, so the default
// is to disable it. If you don't need low latency and are streaming
// lots of small messages, you can change this to 'false'
disableNagleAlgorithm: true,
// The number of milliseconds to wait after sending a close frame
// for an acknowledgement to come back before giving up and just
// closing the socket.
closeTimeout: 5000
};
extend(this.config, config);
if (this.config.httpServer) {
if (!Array.isArray(this.config.httpServer)) {
this.config.httpServer = [this.config.httpServer];
}
var upgradeHandler = this._handlers.upgrade;
this.config.httpServer.forEach(function(httpServer) {
httpServer.on('upgrade', upgradeHandler);
});
}
else {
throw new Error('You must specify an httpServer on which to mount the WebSocket server.');
}
};
WebSocketServer.prototype.unmount = function() {
var upgradeHandler = this._handlers.upgrade;
this.config.httpServer.forEach(function(httpServer) {
httpServer.removeListener('upgrade', upgradeHandler);
});
};
WebSocketServer.prototype.closeAllConnections = function() {
this.connections.forEach(function(connection) {
connection.close();
});
this.pendingRequests.forEach(function(request) {
process.nextTick(function() {
request.reject(503); // HTTP 503 Service Unavailable
});
});
};
WebSocketServer.prototype.broadcast = function(data) {
if (Buffer.isBuffer(data)) {
this.broadcastBytes(data);
}
else if (typeof(data.toString) === 'function') {
this.broadcastUTF(data);
}
};
WebSocketServer.prototype.broadcastUTF = function(utfData) {
this.connections.forEach(function(connection) {
connection.sendUTF(utfData);
});
};
WebSocketServer.prototype.broadcastBytes = function(binaryData) {
this.connections.forEach(function(connection) {
connection.sendBytes(binaryData);
});
};
WebSocketServer.prototype.shutDown = function() {
this.unmount();
this.closeAllConnections();
};
WebSocketServer.prototype.handleUpgrade = function(request, socket) {
var wsRequest = new WebSocketRequest(socket, request, this.config);
try {
wsRequest.readHandshake();
}
catch(e) {
wsRequest.reject(
e.httpCode ? e.httpCode : 400,
e.message,
e.headers
);
return;
}
this.pendingRequests.push(wsRequest);
wsRequest.once('requestAccepted', this._handlers.requestAccepted);
wsRequest.once('requestResolved', this._handlers.requestResolved);
if (!this.config.autoAcceptConnections && utils.eventEmitterListenerCount(this, 'request') > 0) {
this.emit('request', wsRequest);
}
else if (this.config.autoAcceptConnections) {
wsRequest.accept(wsRequest.requestedProtocols[0], wsRequest.origin);
}
else {
wsRequest.reject(404, 'No handler is configured to accept the connection.');
}
};
WebSocketServer.prototype.handleRequestAccepted = function(connection) {
var self = this;
connection.once('close', function(closeReason, description) {
self.handleConnectionClose(connection, closeReason, description);
});
this.connections.push(connection);
this.emit('connect', connection);
};
WebSocketServer.prototype.handleConnectionClose = function(connection, closeReason, description) {
var index = this.connections.indexOf(connection);
if (index !== -1) {
this.connections.splice(index, 1);
}
this.emit('close', connection, closeReason, description);
};
WebSocketServer.prototype.handleRequestResolved = function(request) {
var index = this.pendingRequests.indexOf(request);
if (index !== -1) { this.pendingRequests.splice(index, 1); }
};
module.exports = WebSocketServer;
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