About

An event-driven IPC implementation for NodeJS using unix file sockets

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Table of Contents

About (you are here)

• Quick Start
  • Install
  • A Simple Example
  • More Examples
• Limitations
• Alternate solutions
  • Why this One

Usage

Advanced Usage

API

Quick Start

Want to get up and running quickly? This is for you.

Install

npm install --save @crussell52/socket-ipc

A Simple Example

Client:

const {Client} = require('@crussell52/socket-ipc');
const client = new Client({socketFile: '/tmp/myApp.sock'});

// Say hello as soon as we connect to the server with a simple message
// that give it our name.
client.on('connect', () => client.send('hello', {name: 'crussell52'}));

// Connect. It will auto-retry if the connection fails and auto-reconnect if the connection drops.
client.connect();

Server:

const {Server} = require('@crussell52/socket-ipc');
const server = new Server({socketFile: '/tmp/myApp.sock'});

// Listen for errors so they don't bubble up and kill the app.
server.on('error', err => console.error('IPC Server Error!', err));

// Log all messages. Topics are completely up to the sender!
server.on('message', (message, topic) => console.log(topic, message));

// Say hello back to anybody that sends a message with the "hello" topic. 
server.on('message.hello', (message, clientId) => server.send('hello', `Hello, ${message.name}!`, clientId));

// Start listening for connections.
server.listen();

// Always clean up when you are ready to shut down your app to clean up socket files. If the app
// closes unexpectedly, the server will try to "reclaim" the socket file on the next start.
function shutdown() {
    server.close();
}

More Examples

Check out the /examples directory in the source for more code samples. (Make sure you set the SOCKET_FILE constant at the top of the example files before you run them!)

Limitations

Let's get this out of the way early...

Requires:

• NodeJS >= 8.x LTS (might work with perfectly fine with some older versions -- but not tested)

Transport Support:

• Unix socket files (might work with windows socket files too -- but not tested)

Unsupported Features:

• TCP Sockets
• UDP Sockets
• Windows socket files (well maybe it does, I haven't tried )
• Native client-to-client communication (although you could implement it!)

Love the project, but you need it to do something it doesn't? Open up a feature request!

Alternate solutions

node-ipc ZeroMQ

Why this one?

When I needed to solve this problem, most of what I found was tied to some extra external dependency or platform (electron, redis, etc). The node-ipc lib caught my eye for a time, but I wasn't in love with the interface and it was published under a non-standard (and sometimes considered "satirical") license.

So this package was born. Here are the goals of this project:

• Bidirectional communication over Unix sockets (maybe other transports, in the future)
• Simple interface for sending messages:
  • From the server to a specific client
  • From the server to all clients (broadcast)
  • From any client to the server
• Minimize dependencies (So far, 0!).
• Event driven (using native NodeJS EventEmitter)
• Ability to listen for all messages or to narrow in on specific topics.
• Built-in client resiliency (automatic reconnection, automatic connection retry)
• Extensible design:
  • Pluggable
  • Stable API
  • Thorough docs to make wrapping or extending easy
  • Leave domain details to the domain experts