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, encodePayloadAsBinary, decodePayloadAsBinary.

The browser-side parser also includes encodePayloadAsArrayBuffer and encodePayloadAsBlob.

Example:

var parser = require('engine.io-parser');

var data = new Buffer(5);
for (var i = 0; i < data.length; i++) { data[i] = i; }

parser.encodePacket({ type: 'message', data: data }, function(encoded) {
  var decodedData = parser.decodePacket(encoded); // { type: 'message', data: 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:

1. install the parser package

   npm install engine.io-parser

2. write your app code

   var parser = require('engine.io-parser');
   
   var testBuffer = new Int8Array(10);
   for (var i = 0; i < testBuffer.length; i++) testBuffer[i] = i;
   
   var packets = [{ type: 'message', data: testBuffer.buffer }, { type: 'message', data: 'hello' }];
   
   parser.encodePayload(packets, function(encoded) {
     parser.decodePayload(encoded,
       function(packet, index, total) {
         var isLast = index + 1 == total;
         if (!isLast) {
           var buffer = new Int8Array(packet.data); // testBuffer
         } else {
           var message = packet.data; // 'hello'
         }
       });
   });

3. build your app bundle

   $ browserify app.js > bundle.js

4. 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: optional, 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

• encodeBase64Packet

  • Encodes a packet with binary data in a base64 string (String)
  • Parameters
    • Object: the packet to encode, has type and data
    • Function: callback, returns the base64 encoded message (cb(String))

• decodeBase64Packet

  • Decodes a packet encoded in a base64 string.
  • Parameters
    • String: the base64 encoded message
    • 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
    • Boolean: optional, binary support
    • 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
    • String: optional, the binary type
    • Function: callback, returns (cb(Object: packet, Number:packet index, Number:packet total))

• encodePayloadAsBinary

  • Encodes multiple messages (payload) as binary.
  • Parameters
    • Array: an array of packets
    • Function: callback, returns the encoded payload (cb(Buffer))

• decodePayloadAsBinary

  • Decodes data when a payload is maybe expected. Strings are decoded by interpreting each byte as a key code for entries marked to start with 0. See description of encodePayloadAsBinary.
  • Parameters
    • Buffer: the buffer
    • String: optional, the binary type
    • Function: callback, returns the decoded packet (cb(Object))

Browser

• encodePayloadAsArrayBuffer
  • Encodes multiple messages (payload) as binary.
  • Parameters
    • Array: an array of packets
    • Function: callback, returns the encoded payload (cb(ArrayBuffer))
• encodePayloadAsBlob
  • Encodes multiple messages (payload) as blob.
  • Parameters
    • Array: an array of packets
    • Function: callback, returns the encoded payload (cb(Blob))

Tests

Standalone tests can be run with make test which will run both node.js and browser 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:

./node_modules/.bin/zuul --local 8080 -- test/index.js

Support

The support channels for engine.io-parser are the same as socket.io:

• irc.freenode.net #socket.io
• Google Groups
• Website

Development

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

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

Then:

cd engine.io-parser
npm install

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

License

MIT