express-ws-rpc

Simple JSON RPC over ws or simple-websocket

Installation

npm install --save express-ws-rpc

Server

var express = require('express');
var wsrpc = require('express-ws-rpc');

// create app
var app = express();

// add websocket support to express app
var wss = require('express-ws')(app).wss;

// on websocket request to the root
app.ws('/', function(ws, req) {
	// this function gets called on each connection
	
	// extend ws to decode messages
	wsrpc(ws);
	
	// define method that can be called from the client
	ws.on('addServer', function (a, b, result) {
		result(null, a + b);
	});
	
	// define method depending on the state
	// each connected client owns its own `curr`
	var curr = 0;
	ws.on('next', function (result) {
		result(null, curr++);
	});
	
	// call method that is defined on the client
	ws.call('addClient', 1, 2, function(err, sum) {
		console.log('Client: 1 + 2 = ', sum, err);
	});
});

Client (browserify)

// convert relative WebSocket URL to the absolute one
function getWsAbsoluteUrl(relative) {
	var loc = window.location;
	var proto = loc.protocol === "https:" ? "wss://" : "ws://";
	var port = loc.port || (loc.protocol === "https:" ? 443 : 80);
	return proto + loc.hostname + ":" + port + relative;
}

// create WebSocket client
// I'm not using `ws` here, because it doesn't support
// EventEmitter interface (i.e. the one that lets you call `on`)
var WebSocket = require('simple-websocket');
var ws = new WebSocket(getWsAbsoluteUrl('/'));

// extend ws to decode messages
require('express-ws-rpc')(ws);

// method definition
ws.on('addClient', function (a, b, result) {
	result(null, a + b);
});

// when we get connected
ws.on('connect', function () {
	// call method that is defined on the server
	ws.call('addServer', 10, 20, function (err, sum) {
		console.log('Server: 10 + 20 = ', sum, err);
	});
});

License

MIT

Contribution

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