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