README
socket.io-nats
Adapter to enable broadcasting of events to multiple separate socket.io server nodes through NATS, based on the socket.io-redis
How to use
var io = require('socket.io')(3000);
var nats = require('socket.io-nats');
io.adapter(nats());
By running socket.io with the socket.io-nats
adapter you can run
multiple socket.io instances in different processes or servers that can
all broadcast and emit events to and from each other.
If you need to emit events to socket.io instances from a non-socket.io process, you should use socket.io-nats-emitter.
API
adapter(opts)
The following options are allowed:
key
: the name of the key to pub/sub events on as prefix (socket.io
)delimiter
: optional, channels delimiternc
: optional, the nats client...
: nats client options (ignored if nats client is supplied)
If you decide to supply nc
, make sure you use
node_nats as a client or one
with an equivalent API.
NatsAdapter
The nats adapter instances expose the following properties
that a regular Adapter
does not
uid
prefix
nc
delimiter
Client error handling
Access the nc
property of the
Nats Adapter instance to subscribe to its error
event:
var nats = require('socket.io-nats');
var adapter = nats();
adapter.nats.on('error', function(){});
Custom client (eg: clustered nats)
If you need to create a NatsAdapter to a Nats client instance that has clustered connection
var nats = require('nats');
var servers = ['nats://nats.io:4222', 'nats://nats.io:5222', 'nats://nats.io:6222'];
// Randomly connect to a server in the cluster group.
var nc = nats.connect({'servers': servers});
// currentServer is the URL of the connected server.
console.log("Connected to " + nc.currentServer.host);
var adapter = require('socket.io-nats');
io.adapter(adapter({ nc: nc }));
Protocol
The socket.io-nats
adapter broadcasts and receives messages on particularly named Nats channels. For global broadcasts the channel name is:
prefix + '.' + namespace
In broadcasting to a single room the channel name is:
prefix + '.' + namespace + '.' + room
prefix
: The base channel name. Default value issocket.io
. Changed by settingopts.key
inadapter(opts)
constructordelimiter
: The delimiter of channel name. Default value is.
. Changed by settingopts.delimiter
inadapter(opts)
constructornamespace
: See https://github.com/socketio/socket.io#namespace.room
: Used if targeting a specific room, the room is URL encoded.
License
MIT