Projekt

Obecné

Profil

Stáhnout (12.1 KB) Statistiky
| Větev: | Revize:
1
# faye-websocket
2

    
3
* Travis CI build: [![Build
4
  status](https://secure.travis-ci.org/faye/faye-websocket-node.svg)](http://travis-ci.org/faye/faye-websocket-node)
5
* Autobahn tests: [server](http://faye.jcoglan.com/autobahn/servers/),
6
  [client](http://faye.jcoglan.com/autobahn/clients/)
7

    
8
This is a general-purpose WebSocket implementation extracted from the
9
[Faye](http://faye.jcoglan.com) project. It provides classes for easily building
10
WebSocket servers and clients in Node. It does not provide a server itself, but
11
rather makes it easy to handle WebSocket connections within an existing
12
[Node](http://nodejs.org/) application. It does not provide any abstraction
13
other than the standard [WebSocket API](http://dev.w3.org/html5/websockets/).
14

    
15
It also provides an abstraction for handling
16
[EventSource](http://dev.w3.org/html5/eventsource/) connections, which are
17
one-way connections that allow the server to push data to the client. They are
18
based on streaming HTTP responses and can be easier to access via proxies than
19
WebSockets.
20

    
21

    
22
## Installation
23

    
24
```
25
$ npm install faye-websocket
26
```
27

    
28

    
29
## Handling WebSocket connections in Node
30

    
31
You can handle WebSockets on the server side by listening for HTTP Upgrade
32
requests, and creating a new socket for the request. This socket object exposes
33
the usual WebSocket methods for receiving and sending messages. For example this
34
is how you'd implement an echo server:
35

    
36
```js
37
var WebSocket = require('faye-websocket'),
38
    http      = require('http');
39

    
40
var server = http.createServer();
41

    
42
server.on('upgrade', function(request, socket, body) {
43
  if (WebSocket.isWebSocket(request)) {
44
    var ws = new WebSocket(request, socket, body);
45
    
46
    ws.on('message', function(event) {
47
      ws.send(event.data);
48
    });
49
    
50
    ws.on('close', function(event) {
51
      console.log('close', event.code, event.reason);
52
      ws = null;
53
    });
54
  }
55
});
56

    
57
server.listen(8000);
58
```
59

    
60
`WebSocket` objects are also duplex streams, so you could replace the
61
`ws.on('message', ...)` line with:
62

    
63
```js
64
    ws.pipe(ws);
65
```
66

    
67
Note that under certain circumstances (notably a draft-76 client connecting
68
through an HTTP proxy), the WebSocket handshake will not be complete after you
69
call `new WebSocket()` because the server will not have received the entire
70
handshake from the client yet. In this case, calls to `ws.send()` will buffer
71
the message in memory until the handshake is complete, at which point any
72
buffered messages will be sent to the client.
73

    
74
If you need to detect when the WebSocket handshake is complete, you can use the
75
`onopen` event.
76

    
77
If the connection's protocol version supports it, you can call `ws.ping()` to
78
send a ping message and wait for the client's response. This method takes a
79
message string, and an optional callback that fires when a matching pong message
80
is received. It returns `true` if and only if a ping message was sent. If the
81
client does not support ping/pong, this method sends no data and returns
82
`false`.
83

    
84
```js
85
ws.ping('Mic check, one, two', function() {
86
  // fires when pong is received
87
});
88
```
89

    
90

    
91
## Using the WebSocket client
92

    
93
The client supports both the plain-text `ws` protocol and the encrypted `wss`
94
protocol, and has exactly the same interface as a socket you would use in a web
95
browser. On the wire it identifies itself as `hybi-13`.
96

    
97
```js
98
var WebSocket = require('faye-websocket'),
99
    ws        = new WebSocket.Client('ws://www.example.com/');
100

    
101
ws.on('open', function(event) {
102
  console.log('open');
103
  ws.send('Hello, world!');
104
});
105

    
106
ws.on('message', function(event) {
107
  console.log('message', event.data);
108
});
109

    
110
ws.on('close', function(event) {
111
  console.log('close', event.code, event.reason);
112
  ws = null;
113
});
114
```
115

    
116
The WebSocket client also lets you inspect the status and headers of the
117
handshake response via its `statusCode` and `headers` properties.
118

    
119
To connect via a proxy, set the `proxy` option to the HTTP origin of the proxy,
120
including any authorization information, custom headers and TLS config you
121
require. Only the `origin` setting is required.
122

    
123
```js
124
var ws = new WebSocket.Client('ws://www.example.com/', [], {
125
  proxy: {
126
    origin:  'http://username:password@proxy.example.com',
127
    headers: {'User-Agent': 'node'},
128
    tls:     {cert: fs.readFileSync('client.crt')}
129
  }
130
});
131
```
132

    
133
The `tls` value is a Node 'TLS options' object that will be passed to
134
[`tls.connect()`](http://nodejs.org/api/tls.html#tls_tls_connect_options_callback).
135

    
136

    
137
## Subprotocol negotiation
138

    
139
The WebSocket protocol allows peers to select and identify the application
140
protocol to use over the connection. On the client side, you can set which
141
protocols the client accepts by passing a list of protocol names when you
142
construct the socket:
143

    
144
```js
145
var ws = new WebSocket.Client('ws://www.example.com/', ['irc', 'amqp']);
146
```
147

    
148
On the server side, you can likewise pass in the list of protocols the server
149
supports after the other constructor arguments:
150

    
151
```js
152
var ws = new WebSocket(request, socket, body, ['irc', 'amqp']);
153
```
154

    
155
If the client and server agree on a protocol, both the client- and server-side
156
socket objects expose the selected protocol through the `ws.protocol` property.
157

    
158

    
159
## Protocol extensions
160

    
161
faye-websocket is based on the
162
[websocket-extensions](https://github.com/faye/websocket-extensions-node)
163
framework that allows extensions to be negotiated via the
164
`Sec-WebSocket-Extensions` header. To add extensions to a connection, pass an
165
array of extensions to the `:extensions` option. For example, to add
166
[permessage-deflate](https://github.com/faye/permessage-deflate-node):
167

    
168
```js
169
var deflate = require('permessage-deflate');
170

    
171
var ws = new WebSocket(request, socket, body, [], {extensions: [deflate]});
172
```
173

    
174

    
175
## Initialization options
176

    
177
Both the server- and client-side classes allow an options object to be passed in
178
at initialization time, for example:
179

    
180
```js
181
var ws = new WebSocket(request, socket, body, protocols, options);
182
var ws = new WebSocket.Client(url, protocols, options);
183
```
184

    
185
`protocols` is an array of subprotocols as described above, or `null`.
186
`options` is an optional object containing any of these fields:
187

    
188
* `extensions` - an array of
189
  [websocket-extensions](https://github.com/faye/websocket-extensions-node)
190
  compatible extensions, as described above
191
* `headers` - an object containing key-value pairs representing HTTP headers to
192
  be sent during the handshake process
193
* `maxLength` - the maximum allowed size of incoming message frames, in bytes.
194
  The default value is `2^26 - 1`, or 1 byte short of 64 MiB.
195
* `ping` - an integer that sets how often the WebSocket should send ping frames,
196
  measured in seconds
197

    
198
The client accepts some additional options:
199

    
200
* `proxy` - settings for a proxy as described above
201
* `tls` - a Node 'TLS options' object containing TLS settings for the origin
202
  server, this will be passed to
203
  [`tls.connect()`](http://nodejs.org/api/tls.html#tls_tls_connect_options_callback)
204
* `ca` - (legacy) a shorthand for passing `{tls: {ca: value}}`
205

    
206

    
207
## WebSocket API
208

    
209
Both server- and client-side `WebSocket` objects support the following API.
210

    
211
* <b>`on('open', function(event) {})`</b> fires when the socket connection is
212
  established. Event has no attributes.
213
* <b>`on('message', function(event) {})`</b> fires when the socket receives a
214
  message. Event has one attribute, <b>`data`</b>, which is either a `String`
215
  (for text frames) or a `Buffer` (for binary frames).
216
* <b>`on('error', function(event) {})`</b> fires when there is a protocol error
217
  due to bad data sent by the other peer. This event is purely informational,
218
  you do not need to implement error recover.
219
* <b>`on('close', function(event) {})`</b> fires when either the client or the
220
  server closes the connection. Event has two optional attributes, <b>`code`</b>
221
  and <b>`reason`</b>, that expose the status code and message sent by the peer
222
  that closed the connection.
223
* <b>`send(message)`</b> accepts either a `String` or a `Buffer` and sends a
224
  text or binary message over the connection to the other peer.
225
* <b>`ping(message, function() {})`</b> sends a ping frame with an optional
226
  message and fires the callback when a matching pong is received.
227
* <b>`close(code, reason)`</b> closes the connection, sending the given status
228
  code and reason text, both of which are optional.
229
* <b>`version`</b> is a string containing the version of the `WebSocket`
230
  protocol the connection is using.
231
* <b>`protocol`</b> is a string (which may be empty) identifying the subprotocol
232
  the socket is using.
233

    
234

    
235
## Handling EventSource connections in Node
236

    
237
EventSource connections provide a very similar interface, although because they
238
only allow the server to send data to the client, there is no `onmessage` API.
239
EventSource allows the server to push text messages to the client, where each
240
message has an optional event-type and ID.
241

    
242
```js
243
var WebSocket   = require('faye-websocket'),
244
    EventSource = WebSocket.EventSource,
245
    http        = require('http');
246

    
247
var server = http.createServer();
248

    
249
server.on('request', function(request, response) {
250
  if (EventSource.isEventSource(request)) {
251
    var es = new EventSource(request, response);
252
    console.log('open', es.url, es.lastEventId);
253
    
254
    // Periodically send messages
255
    var loop = setInterval(function() { es.send('Hello') }, 1000);
256
    
257
    es.on('close', function() {
258
      clearInterval(loop);
259
      es = null;
260
    });
261
  
262
  } else {
263
    // Normal HTTP request
264
    response.writeHead(200, {'Content-Type': 'text/plain'});
265
    response.end('Hello');
266
  }
267
});
268

    
269
server.listen(8000);
270
```
271

    
272
The `send` method takes two optional parameters, `event` and `id`. The default
273
event-type is `'message'` with no ID. For example, to send a `notification`
274
event with ID `99`:
275

    
276
```js
277
es.send('Breaking News!', {event: 'notification', id: '99'});
278
```
279

    
280
The `EventSource` object exposes the following properties:
281

    
282
* <b>`url`</b> is a string containing the URL the client used to create the
283
  EventSource.
284
* <b>`lastEventId`</b> is a string containing the last event ID received by the
285
  client. You can use this when the client reconnects after a dropped connection
286
  to determine which messages need resending.
287

    
288
When you initialize an EventSource with ` new EventSource()`, you can pass
289
configuration options after the `response` parameter. Available options are:
290

    
291
* <b>`headers`</b> is an object containing custom headers to be set on the
292
  EventSource response.
293
* <b>`retry`</b> is a number that tells the client how long (in seconds) it
294
  should wait after a dropped connection before attempting to reconnect.
295
* <b>`ping`</b> is a number that tells the server how often (in seconds) to send
296
  'ping' packets to the client to keep the connection open, to defeat timeouts
297
  set by proxies. The client will ignore these messages.
298

    
299
For example, this creates a connection that allows access from any origin, pings
300
every 15 seconds and is retryable every 10 seconds if the connection is broken:
301

    
302
```js
303
var es = new EventSource(request, response, {
304
  headers: {'Access-Control-Allow-Origin': '*'},
305
  ping:    15,
306
  retry:   10
307
});
308
```
309

    
310
You can send a ping message at any time by calling `es.ping()`. Unlike
311
WebSocket, the client does not send a response to this; it is merely to send
312
some data over the wire to keep the connection alive.
313

    
314

    
315
## License
316

    
317
(The MIT License)
318

    
319
Copyright (c) 2010-2015 James Coglan
320

    
321
Permission is hereby granted, free of charge, to any person obtaining a copy of
322
this software and associated documentation files (the 'Software'), to deal in
323
the Software without restriction, including without limitation the rights to
324
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
325
the Software, and to permit persons to whom the Software is furnished to do so,
326
subject to the following conditions:
327

    
328
The above copyright notice and this permission notice shall be included in all
329
copies or substantial portions of the Software.
330

    
331
THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
332
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
333
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
334
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
335
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
336
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
(2-2/3)