File size: 4,501 Bytes
48e84aa
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159

# engine.io-parser

[![Build Status](https://github.com/socketio/engine.io-parser/workflows/CI/badge.svg?branch=main)](https://github.com/socketio/engine.io-parser/actions)
[![NPM version](https://badge.fury.io/js/engine.io-parser.svg)](https://npmjs.com/package/engine.io-parser)

This is the JavaScript parser for the engine.io protocol encoding,
shared by both
[engine.io-client](https://github.com/socketio/engine.io-client) and
[engine.io](https://github.com/socketio/engine.io).

## How to use

### Standalone

The parser can encode/decode packets, payloads, and payloads as binary
with the following methods: `encodePacket`, `decodePacket`, `encodePayload`,
`decodePayload`.

Example:

```js
const parser = require("engine.io-parser");
const data = Buffer.from([ 1, 2, 3, 4 ]);

parser.encodePacket({ type: "message", data }, encoded => {
  const decodedData = parser.decodePacket(encoded); // decodedData === data
});
```

### With browserify

Engine.IO Parser is a commonjs module, which means you can include it by using
`require` on the browser and package using [browserify](http://browserify.org/):

1. install the parser package

    ```shell
    npm install engine.io-parser
    ```

1. write your app code

    ```js
    const parser = require("engine.io-parser");

    const testBuffer = new Int8Array(10);
    for (let i = 0; i < testBuffer.length; i++) testBuffer[i] = i;

    const packets = [{ type: "message", data: testBuffer.buffer }, { type: "message", data: "hello" }];

    parser.encodePayload(packets, encoded => {
      parser.decodePayload(encoded,
        (packet, index, total) => {
          const isLast = index + 1 == total;
          if (!isLast) {
            const buffer = new Int8Array(packet.data); // testBuffer
          } else {
            const message = packet.data; // "hello"
          }
        });
    });
    ```

1. build your app bundle

    ```bash
    $ browserify app.js > bundle.js
    ```

1. include on your page

    ```html
    <script src="/path/to/bundle.js"></script>
    ```

## Features

- Runs on browser and node.js seamlessly
- Runs inside HTML5 WebWorker
- Can encode and decode packets
  - Encodes from/to ArrayBuffer or Blob when in browser, and Buffer or ArrayBuffer in Node

## API

Note: `cb(type)` means the type is a callback function that contains a parameter of type `type` when called.

### Node

- `encodePacket`
    - Encodes a packet.
    - **Parameters**
      - `Object`: the packet to encode, has `type` and `data`.
        - `data`: can be a `String`, `Number`, `Buffer`, `ArrayBuffer`
      - `Boolean`: binary support
      - `Function`: callback, returns the encoded packet (`cb(String)`)
- `decodePacket`
    - Decodes a packet. Data also available as an ArrayBuffer if requested.
    - Returns data as `String` or (`Blob` on browser, `ArrayBuffer` on Node)
    - **Parameters**
      - `String` | `ArrayBuffer`: the packet to decode, has `type` and `data`
      - `String`: optional, the binary type

- `encodePayload`
    - Encodes multiple messages (payload).
    - If any contents are binary, they will be encoded as base64 strings. Base64
      encoded strings are marked with a b before the length specifier
    - **Parameters**
      - `Array`: an array of packets
      - `Function`: callback, returns the encoded payload (`cb(String)`)
- `decodePayload`
    - Decodes data when a payload is maybe expected. Possible binary contents are
      decoded from their base64 representation.
    - **Parameters**
      - `String`: the payload
      - `Function`: callback, returns (cb(`Object`: packet, `Number`:packet index, `Number`:packet total))

## Tests

Standalone tests can be run with `npm test` which will run the node.js tests.

Browser tests are run using [zuul](https://github.com/defunctzombie/zuul).
(You must have zuul setup with a saucelabs account.)

You can run the tests locally using the following command:

```
npm run test:browser
```

## Support

The support channels for `engine.io-parser` are the same as `socket.io`:
  - irc.freenode.net **#socket.io**
  - [Github Discussions](https://github.com/socketio/socket.io/discussions)
  - [Website](https://socket.io)

## Development

To contribute patches, run tests or benchmarks, make sure to clone the
repository:

```bash
git clone git://github.com/socketio/engine.io-parser.git
```

Then:

```bash
cd engine.io-parser
npm ci
```

See the `Tests` section above for how to run tests before submitting any patches.

## License

MIT