yamux-js

Yamux-js

Yamux-js (Yet another Multiplexer) is a Node.js (TypeScript/JavaScript) port of the multiplexing library for Golang made by HashiCorp: https://github.com/hashicorp/yamux. The 2 libraries are fully interoperable (you can have a client in Golang and a server in JS, or the other way around).

From https://github.com/hashicorp/yamux:

It relies on an underlying connection to provide reliability and ordering, such as TCP or Unix domain sockets, and provides stream-oriented multiplexing. It is inspired by SPDY but is not interoperable with it.

Yamux features include:

• Bi-directional streams
  • Streams can be opened by either client or server
  • Useful for NAT traversal
  • Server-side push support
• Flow control
  • Avoid starvation
  • Back-pressure to prevent overwhelming a receiver
• Keep Alives
  • Enables persistent connections over a load balancer
• Efficient
  • Enables thousands of logical streams with low overhead

Installation

Install Yamux-js using yarn:

yarn add yamux-js

Or npm:

npm install --save yamux-js

Usage

Client side

var {Client} = require('yamux-js');

var client = new Client();
client.on('error', (err) => {
    console.log('An error occured:', err);
});
client.pipe(commonXXXChannel).pipe(client);

var stream1 = client.open();
stream1.on('end', () => {
    console.log('client disconnected');
});
stream1.on('data', (data) => {
    console.log('recv:', data.toString());
});
stream1.on('error', (err) => {
    console.log('An error occured:', err);
});
stream1.write('Sending data');

var stream2 = client.open();
// ...

Server side

var {Server} = require('yamux-js');

var server = new Server((stream) => {
    stream.on('end', () => {
        console.log('client disconnected');
    });
    stream.on('data', (data) => {
        console.log('recv:', data.toString());
        stream.write('Sending back data');
    });
    stream.on('error', (err) => {
        console.log('An error occured:', err);
    });
});
server.on('error', (err) => {
    console.log('An error occured:', err);
});

server.pipe(commonXXXChannel).pipe(server);

See also a full example with net.createServer

Configuration

Both Server and Client can take a custom config as last argument in their constructor:

{
    // AcceptBacklog is used to limit how many streams may be
    // waiting an accept.
    // WARNING [Difference with the Go implementation]: total number of streams, not in-flight
    acceptBacklog: number; // default: 256

    // EnableKeepalive is used to do a period keep alive
    // messages using a ping.
    enableKeepAlive: boolean; // default: true

    // KeepAliveInterval is how often to perform the keep alive
    keepAliveInterval: number; // In seconds, default: 30

    // ConnectionWriteTimeout is meant to be a "safety valve" timeout after
    // we which will suspect a problem with the underlying connection and
    // close it. This is only applied to writes, where's there's generally
    // an expectation that things will move along quickly.
    connectionWriteTimeout: number; // In seconds, default: 10

    // MaxStreamWindowSize is used to control the maximum
    // window size that we allow for a stream.
    maxStreamWindowSize: number; // default: 256 * 1024 (256 KB)

    // Logger is used to pass in the logger to be used.
    logger: typeof console.log; // default: console.log
}