faye-websocket

What is faye-websocket?

The faye-websocket npm package is a WebSocket client and server implementation that allows you to build real-time web applications. It provides an easy-to-use API for handling WebSocket connections and messages.

What are faye-websocket's main functionalities?

WebSocket Client

This code sample demonstrates how to create a WebSocket client that connects to a server, sends a message, and listens for messages and the close event.

const WebSocket = require('faye-websocket');
const ws = new WebSocket.Client('ws://www.example.com/');

ws.on('open', function(event) {
  console.log('Connection established');
  ws.send('Hello, world!');
});

ws.on('message', function(event) {
  console.log('Received message: ' + event.data);
});

ws.on('close', function(event) {
  console.log('Connection closed', event.code, event.reason);
  ws = null;
});

WebSocket Server

This code sample shows how to set up a WebSocket server that can accept connections, echo received messages back to the client, and handle the close event.

const http = require('http');
const WebSocket = require('faye-websocket');

const server = http.createServer();

server.on('upgrade', function(request, socket, body) {
  if (WebSocket.isWebSocket(request)) {
    const ws = new WebSocket(request, socket, body);

    ws.on('message', function(event) {
      ws.send(event.data);
    });

    ws.on('close', function(event) {
      console.log('Connection closed', event.code, event.reason);
      ws = null;
    });
  }
});

server.listen(3000);

Other packages similar to faye-websocket

ws

The 'ws' package is a popular WebSocket implementation for Node.js. It is similar to faye-websocket but is more widely used and actively maintained. It offers a simpler interface for WebSocket communication and is known for its performance and compliance with the WebSocket protocol.

socket.io

Socket.IO is a library that enables real-time, bidirectional and event-based communication between web clients and servers. It is more feature-rich than faye-websocket, providing fallbacks for older browsers, automatic reconnection, and a higher-level event-driven API.

websocket

The 'websocket' package provides both client and server-side implementations of the WebSocket protocol. It is similar to faye-websocket but offers additional features such as WebSocket extensions and a wider range of subprotocols.

README

faye-websocket

This is a robust, general-purpose WebSocket implementation extracted from the Faye project. It provides classes for easily building WebSocket servers and clients in Node. It does not provide a server itself, but rather makes it easy to handle WebSocket connections within an existing Node application. It does not provide any abstraction other than the standard WebSocket API.

The server-side socket can process draft-75, draft-76, hybi-07 and later versions of the protocol. It selects protocol versions automatically, supports both text and binary messages, and transparently handles ping, pong, close and fragmented messages.

Accepting WebSocket connections in Node

You can handle WebSockets on the server side by listening for HTTP Upgrade requests, and creating a new socket for the request. This socket object exposes the usual WebSocket methods for receiving and sending messages. For example this is how you'd implement an echo server:

var WebSocket = require('faye-websocket'),
    http      = require('http');

var server = http.createServer();

server.addListener('upgrade', function(request, socket, head) {
  var ws = new WebSocket(request, socket, head);
  
  ws.onmessage = function(event) {
    ws.send(event.data);
  };
  
  ws.onclose = function(event) {
    console.log('close', event.code, event.reason);
    ws = null;
  };
});

server.listen(8000);

Using the WebSocket client

The client supports both the plain-text ws protocol and the encrypted wss protocol, and has exactly the same interface as a socket you would use in a web browser. On the wire it identifies itself as hybi-13, though it's compatible with servers speaking later versions of the protocol.

var WebSocket = require('faye-websocket'),
    ws        = new WebSocket.Client('ws://www.example.com/');

ws.onopen = function(event) {
  console.log('open');
  ws.send('Hello, world!');
};

ws.onmessage = function(event) {
  console.log('message', event.data);
};

ws.onclose = function(event) {
  console.log('close', event.code, event.reason);
  ws = null;
};

Subprotocol negotiation

The WebSocket protocol allows peers to select and identify the application protocol to use over the connection. On the client side, you can set which protocols the client accepts by passing a list of protocol names when you construct the socket:

var ws = new WebSocket.Client('ws://www.example.com/', ['irc', 'amqp']);

On the server side, you can likewise pass in the list of protocols the server supports after the other constructor arguments:

var ws = new WebSocket(request, socket, head, ['irc', 'amqp']);

If the client and server agree on a protocol, both the client- and server-side socket objects expose the selected protocol through the ws.protocol property. If they cannot agree on a protocol to use, the client closes the connection.

WebSocket API

The WebSocket API consists of several event handlers and a method for sending messages.

• onopen fires when the socket connection is established. Event has no attributes.
• onerror fires when the connection attempt fails. Event has no attributes.
• onmessage fires when the socket receives a message. Event has one attribute, data, which is either a String (for text frames) or a Buffer (for binary frames).
• onclose fires when either the client or the server closes the connection. Event has two optional attributes, code and reason, that expose the status code and message sent by the peer that closed the connection.
• send(message) accepts either a String or a Buffer and sends a text or binary message over the connection to the other peer.
• close(code, reason) closes the connection, sending the given status code and reason text, both of which are optional.
• protocol is a string or null identifying the subprotocol the socket is using.

License

(The MIT License)

Copyright (c) 2009-2011 James Coglan

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.