[in-duplex, binary streams] # ie.- #double #binding #binary #streams in browser #bundles using #socket.io #client/server

binary-streams.duplex.md

Installation

npm install socket.io-stream

Usage

If you are not familiar with Stream API, be sure to check out the docs. I also recommend checking out the awesome Stream Handbook.

For streaming between server and client, you will send stream instances first. To receive streams, you just wrap socket with socket.io-stream, then listen any events as usual.

Server:

var io = require('socket.io').listen(80);

var ss = require('socket.io-stream');

var path = require('path');

io.of('/user').on('connection', function(socket) {

ss(socket).on('profile-image', function(stream, data) {

var filename = path.basename(data.name);

stream.pipe(fs.createWriteStream(filename));

});

});

createStream() returns a new stream which can be sent by emit().

Client:

var io = require('socket.io-client');

var ss = require('socket.io-stream');

var socket = io.connect('http://example.com/user');

var stream = ss.createStream();

var filename = 'profile.jpg';

ss(socket).emit('profile-image', stream, {name: filename});

fs.createReadStream(filename).pipe(stream);

You can stream data from a client to server, and vice versa.

// send data

ss(socket).on('file', function(stream) {

fs.createReadStream('/path/to/file').pipe(stream);

});

// receive data

ss(socket).emit('file', stream);

stream.pipe(fs.createWriteStream('file.txt'));

Browser

This module can be used on the browser. To do so, just copy a file to a public directory.

$ cp node_modules/socket.io-stream/socket.io-stream.js somewhere/public/

You can also use browserify to create your own bundle.

$ npm install browserify -g
$ cd node_modules/socket.io-stream
$ browserify index.js -s ss > socket.io-stream.js

<script src="/socket.io/socket.io.js"></script> <script src="/js/socket.io-stream.js"></script> <script src="/js/jquery.js"></script> <script> $(function() { var socket = io.connect('/foo'); $('#file').change(function(e) { var file = e.target.files[0]; var stream = ss.createStream(); // upload a file to the server. ss(socket).emit('file', stream, {size: file.size}); ss.createBlobReadStream(file).pipe(stream); }); }); </script>

Upload progress

You can track upload progress like the following:

var blobStream = ss.createBlobReadStream(file);

var size = 0;

blobStream.on('data', function(chunk) {

size += chunk.length;

console.log(Math.floor(size / file.size * 100) + '%');

// -> e.g. '42%'

});

blobStream.pipe(stream);

Socket.IO v0.9 support

You have to set forceBase64 option true when using the library with socket.io v0.9.x.

ss.forceBase64 = true;

Documentation

ss(sio)

• sio socket.io Socket A socket of Socket.IO, both for client and server
• return Socket

Look up an existing Socket instance based on sio (a socket of Socket.IO), or create one if it doesn't exist.

socket.emit(event, [arg1], [arg2], [...])

• event String The event name

Emit an event with variable number of arguments including at least a stream.

ss(socket).emit('myevent', stream, {name: 'thefilename'}, function() { ... });

// send some streams at a time.

ss(socket).emit('multiple-streams', stream1, stream2);

// as members of array or object.

ss(socket).emit('flexible', [stream1, { foo: stream2 }]);

// get streams through the ack callback

ss(socket).emit('ack', function(stream1, stream2) { ... });

socket.on(event, listener)

• event String The event name
• listener Function The event handler function

Add a listener for event. listener will take stream(s) with any data as arguments.

ss(socket).on('myevent', function(stream, data, callback) { ... });

// access stream options

ss(socket).on('foo', function(stream) {

if (stream.options && stream.options.highWaterMark > 1024) {

console.error('Too big highWaterMark.');

return;

}

});

ss.createStream([options])

• options Object
  • highWaterMark Number
  • encoding String
  • decodeStrings Boolean
  • objectMode Boolean
  • allowHalfOpen Boolean if true, then the stream won't automatically close when the other endpoint ends. Default to false.
• return Duplex Stream

Create a new duplex stream. See the docs for the details of stream and options.

var stream = ss.createStream();

// with options

var stream = ss.createStream({

highWaterMark: 1024,

objectMode: true,

allowHalfOpen: true

});

ss.createBlobReadStream(blob, [options])

• options Object
  • highWaterMark Number
  • encoding String
  • objectMode Boolean
• return Readable Stream

Create a new readable stream for Blob and File on browser. See the docs for the details of stream and options.

var stream = ss.createBlobReadStream(new Blob([1, 2, 3]));

ss.Buffer

Node Buffer class to use on browser, which is exposed for convenience. On Node environment, you should just use normal Buffer.

var stream = ss.createStream();

stream.write(new ss.Buffer([0, 1, 2]));

License

MIT

Keywords

• stream
• socket.io
• binary
• file
• upload

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