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node-walve

walve is a stream based WebSocket implementation for node.js.

var walve = require('walve');

walve.createServer(function(wsocket) {
  wsocket.on('incoming', function(incoming) {
    // handle readable incoming stream
  });
}).listen(server);

Examples

You can find working examples in the /opt directory of this project.

  • echo: echos messages back to the browser
  • sugar: extends Server with some api sugar
  • stream: streams file through websocket to document
  • cluster: streams file through websocket cluster (hot concurrency)

Furthermore there are currently two real world examples using walve. Feel free to add own projects:

  • nearby real time geolocation tracking with walve and google maps
  • messenger real time messenger with support for image streaming

Installation

The package is available on npm as walve.

npm install --save walve

Documentation

Server

new Server([options])

Creates a new Server instance. Valid options are for example url which can be used to have multiple websocket servers on one http server.

Event: "connect"

Emitted when a new WebSocket upgrade was established. Provides instance of Socket as argument.

Event: "error"

Emitted when an error occurs. For example on failed upgrade.

server.listen(http)

Listens on the "upgrade" event of the http instance.

Socket

Abstracts a single WebSocket connection.

new Socket(socket)

Creates a new duplex stream Socket which reads and writes from the underlaying TCP socket.

Event: "incoming"

wsocket.on('incoming', function(incoming) {
  incoming.pipe(process.stdout, { end: false });
});

Emitted when a WebSocket frame is received. First argument is a an instance of Incoming.

Event: "end"

Emitted when the TCP connection closes.

socket.end

wsocket.end();
// actually better:
var outgoing = new Outgoing({ opcode: 0x08 });
outgoing.pipe(socket);
outgoing.end();

Will completly close the TCP socket.

Incoming

Abstracts an incoming WebSocket frame.

new Incoming()

Creates a new instance of the Incoming transform stream. Which transforms incoming WebSocket frames to node buffers.

incoming.header

if (incoming.header.opcode === 0x01) {
    // handle data as unicode
}

Contains fin, opcode, length and so on. You will mainly be interested in header.opcode as the other values are more for internal use.

Event: "readable"

var message = '';

incoming.on('readable', function() {
  message += incoming.read().toString();
});

Emitted when there is payload to read from the frame.

Event: "end"

incoming.on('end', function() {
  // log prev buffered messages
  console.log(message);
});

Emitted when frame ends and data was consumed with incoming.read().

Outgoing

Abstracts an outgoing WebSocket frame.

new Outgoing([options])

Returns a new instance of Outgoing transform stream. As this is a transform and not a writable stream you must pipe outgoing to the websocket socket provided by the server "connect" event. Options can contain a header object. See below for more.

outgoing.header

outgoing.header.final = true;
outgoing.header.masked = false;
outgoing.header.opcode = 0x01;
outgoing.header.length = 0x0a;

outgoing.write('Hello World').pipe(wsocket, { end: false });

Sets the header information of an outgoing frame. You can omit final and opcode as they will use most common default values true and 0x01 (text frame).

License

Copyright 2014 Bodo Kaiser i@bodokaiser.io

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.