socket.io-emitter

socket.io-emitter allows you to communicate with Socket.IO servers easily from another Node.js process (server side).

The emitter is also available in other programming languages:

• Java: https://github.com/sunsus/socket.io-java-emitter
• Python: https://pypi.org/project/socket.io-emitter/
• PHP: https://github.com/rase-/socket.io-php-emitter
• Golang: https://github.com/yosuke-furukawa/socket.io-go-emitter
• Perl: https://metacpan.org/pod/SocketIO::Emitter
• Rust: https://github.com/epli2/socketio-rust-emitter

It must be used in conjunction with socket.io-redis.

The current version is compatible with both:

• socket.io-redis@5 (socket.io@2)
• socket.io-redis@6 (socket.io@3)

Table of content

• How to use
• Examples
• Error handling
• API
  • Emitter(client[, opts])
  • Emitter(clientUri[, opts])
  • Emitter(opts)
  • Emitter#to(room:String):Emitter
  • Emitter#in(room:String):Emitter
  • Emitter#of(namespace:String):Emitter
• License

How to use

const io = require('socket.io-emitter')({ host: '127.0.0.1', port: 6379 });
setInterval(() => {
  io.emit('time', new Date);
}, 5000);

// Different constructor options.

//1. Initialize with host:port string
const io = require('socket.io-emitter')("localhost:6379")
// 2. Initlize with host, port object.
const io = require('socket.io-emitter')({ host: '127.0.0.1', port: 6379 });
// 3. Can use other node_redis compatible client eg; ioredis.

const Redis = require("ioredis");
const redis = new Redis();
const io = require('socket.io-emitter')(redis);

// Make the emitter works with redis clustered environment.
const Cluster = new Redis.Cluster([
    {
        host: "localhost",
        port: 6379
    },
    {
        host: "localhost",
        port: 6378
    },
]);
const io = require('socket.io-emitter')(Cluster);

Examples

const io = require('socket.io-emitter')({ host: '127.0.0.1', port: 6379 });

// sending to all clients
io.emit('broadcast', /* ... */);

// sending to all clients in 'game' room
io.to('game').emit('new-game', /* ... */);

// sending to individual socketid (private message)
io.to(socketId).emit('private', /* ... */);

const nsp = io.of('/admin');

// sending to all clients in 'admin' namespace
nsp.emit('namespace', /* ... */);

// sending to all clients in 'admin' namespace and in 'notifications' room
nsp.to('notifications').emit('namespace', /* ... */);

Note: acknowledgements are not supported

Error handling

Access the redis to subscribe to its error event:

const emitter = require('socket.io-emitter')("localhost:6379");

emitter.redis.on('error', (err) => {
  console.log(err);
});

API

Emitter(client[, opts])

client is a node_redis compatible client that has been initialized with the return_buffers option set to true. This argument is optional.

The following options are allowed:

• key: the name of the key to pub/sub events on as prefix (socket.io)
• host: host to connect to redis on (localhost)
• port: port to connect to redis on (6379)
• socket: unix domain socket to connect to redis on ("/tmp/redis.sock")

Emitter(clientUri[, opts])

Same as above, but clientUri is a string of the format host:port to connect to redis to.

Emitter(opts)

If you don't want to supply a redis client object, and want socket.io-emitter to intiialize one for you, make sure to supply the host and port options.

Emitter#to(room:String):Emitter

Emitter#in(room:String):Emitter

Specifies a specific room that you want to emit to.

Emitter#of(namespace:String):Emitter

Specifies a specific namespace that you want to emit to.

License

MIT