engine.io-parser

This is the JavaScript parser for the engine.io protocol encoding, shared by both engine.io-client and 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:

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:

install the parser package
```
npm install engine.io-parser
```

write your app code

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"
      }
    });
});

build your app bundle
```
$ browserify app.js > bundle.js
```

include on your page

<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. (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
Website

Development

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

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

Then:

cd engine.io-parser
npm ci

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

License

MIT

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