bm-server

#!/usr/bin/env node

process.title = 'bm-server';
var webSocketServer = require('websocket').server;
require('dotenv').config();
var http = require(process.env.KEY && process.env.CERT ? 'https' : 'http');
const fs = require('fs');
const log=str=>console.log(`[${new Date().toLocaleString()}] - ${str}`);

// if a port number is passedinto the command, use that, else default to 1337
var port = (process.argv[2]||"").trim() || 1337;

var sessions = {};

var server;
if(process.env.KEY && process.env.CERT){
	var opts = {
		key: fs.readFileSync(process.env.KEY),
		cert: fs.readFileSync(process.env.CERT),
	};
	if(process.env.CA) opts.ca = process.env.CA
	server = http.createServer(opts, function(request, response){});
}else{
	server = http.createServer(function(request, response){});
}
  

server.listen(port, function(){
	log(`Server active on port ${port}`);
});

var wsServer = new webSocketServer({
	httpServer: server
});

// Given an array of objects with w and h values will return 
// a new object with the minimum values
const getMinDims = d => d.reduce((acc, cur)=>{
	if(!acc.w || acc.w > cur.w) acc.w = cur.w;
	if(!acc.h || acc.h > cur.h) acc.h = cur.h;
	return acc;
}, {w:0, h:0});

// Given an array of objects with w and h values (d),
// an object that matches at least one of the objects in the array (c),
// and a new object with a w and h value (n),
// will replace c with n in the array d and return it
const replaceValue  = (d, c, n) => d.reduce((a, i)=>{
	if(i.w == c.w && i.h == c.h) i = n;
	a.push(i);
	return a;
}, []);

wsServer.on('request', function (request) {
	var connection = request.accept(null, request.origin);	
	var role, session, index, myDims, browser;
	
	const broadcastSessionUpdate = (msg)=>{
		[session.master, ...session.slaves].forEach(con=>{
			if(!con) return;
			con.sendUTF(JSON.stringify({
				action: 'session_update', 
				slaves: session.slaves.length,
				members: session.master ? session.slaves.length+1 : session.slaves.length,
				session_id: session.id,
				started: session.started,
				message: msg || ""
			}));
		});
	};
	
	connection.on('message', function (message) {
		var data = JSON.parse(message.utf8Data);
		switch(data.action){
			case "init_session":
				if(data.role === 'master'){
					if(!sessions[data.sessionid]) sessions[data.sessionid] = {id:data.sessionid, serverBrowser:"", master:null, slaves:[], started:false, forceBrowser:0, dimensions: {d:[], report_cnt:0, ready_cnt:0}};
					session = sessions[data.sessionid];
					if(!!session.master && connection){
						connection.sendUTF(JSON.stringify({
							action: 'session_error', 
							message: 'There is already a master assigned for this session.'
						}));
					}
					
					session.master = connection;
					role = 'master';
					
					broadcastSessionUpdate('Leader has joined session.');
					browser = data.browser;
					session.serverBrowser = data.browser;
					session.forceBrowser = data.forceBrowser;
				}else{
					
					if(!sessions[data.sessionid] && connection){
						log('Attempted to join session afer it has ended.');
						connection.sendUTF(JSON.stringify({
							action: 'session_error', 
							message: 'This session has already ended.'
						}));
						return;
					}
					
					session = sessions[data.sessionid];
					if(session.started && connection){
						log('Attempted to join session afer it has started.');
						connection.sendUTF(JSON.stringify({
							action: 'session_error', 
							message: 'This session has already started. It\'s too late to join.'
						}));
						return;
					}
				
					if(session.forceBrowser > 0 && session.serverBrowser !== data.browser){
						if(session.forceBrowser == 1){
							log('Attempted to join session with wrong browser: '+data.browser+", "+session.serverBrowser+" is required.");
							if(connection) connection.sendUTF(JSON.stringify({
								action: 'session_error', 
								message: `You are using ${data.browser}, but this session requires you to use ${session.serverBrowser}. Please try again in ${session.serverBrowser}.`
							}));
							broadcastSessionUpdate(`Member attempted to join session using ${data.browser}... Member is switching to ${session.serverBrowser} now.`);
						}else if(session.forceBrowser == 2){
							log('Confirming join session with browser: '+data.browser+", "+session.serverBrowser+" is recommended.");
							if(connection) connection.sendUTF(JSON.stringify({
								action: 'session_confirm', 
								confirm_action: 'browser_type',
								message: `You are using ${data.browser}, but this session recommends that you use ${session.serverBrowser}. Would you like to continue in ${data.browser} anyway?`
							}));
							broadcastSessionUpdate(`Member attempted to join session using ${data.browser}... Confirming.`);
						}
						return;
					}
				
					index = session.slaves.length;
					session.slaves.push(connection);
					role = 'slave';
					
					broadcastSessionUpdate('Member has joined session.');
				}
				log(`${role} joined session: ${data.sessionid}`);
				break;
			
			case "respond_confirm":
				switch(data.confirm_action){
					case "browser_type":
						if(!data.confirm && connection){
							log('Failed to confirm browser usage.');
							connection.sendUTF(JSON.stringify({
								action: 'session_error', 
								message: `Failed to confirm browser usage.`
							}));
						}else{
							log('Confirmed use of unrecommended browser.');
							index = session.slaves.length;
							session.slaves.push(connection);
							role = 'slave';
							broadcastSessionUpdate('Member has joined session.');
						}
						break;
				}
				break;
			
			case "set_state":
				if(role !== 'master') break;
				session.slaves.forEach(slave=>{
					if(null === slave) return;
					slave.sendUTF(JSON.stringify({
						action: 'set_state', 
						state: data.state
					}));
				});
				break;
				
			case "set_passthru_state":
				if(role !== 'master') break;
				session.slaves.forEach(slave=>{
					if(null === slave) return;
					slave.sendUTF(JSON.stringify({
						action: 'set_passthru_state', 
						state: data.state
					}));
				});
				break;
			
			case 'resize_ready':
				session.dimensions.ready_cnt++;
				var total_members = session.slaves.length+1;
				if(total_members === session.dimensions.ready_cnt && session.master){
					session.master.sendUTF(JSON.stringify({
						action: 'all_members_resized', 
					}));
				}
				break;
			
			case 'resize_all':
				session.dimensions.d = replaceValue(session.dimensions.d, myDims, data.dimensions);
				myDims = data.dimensions;
				var minDims = getMinDims(session.dimensions.d);
				if(minDims.w == data.dimensions.w || minDims.h == data.dimensions.h){
					var data = JSON.stringify({
						action: 'resize', 
						dimensions: {
							h: minDims.h,
							w: minDims.w
						}
					});
					if(session.master) session.master.sendUTF(data);
					session.slaves.forEach(slave=>{
						if(null === slave) return;
						slave.sendUTF(data);
					});
				}
				break;
			
			case 'report_dims':
				myDims = data.dimensions;
				session.dimensions.d.push(myDims);
				session.dimensions.report_cnt++;
				if(session.slaves.length === session.dimensions.report_cnt){
					var minDims = getMinDims(session.dimensions.d);
					var data = JSON.stringify({
						action: 'init_browser_resize', 
						dimensions: {
							h: minDims.h,
							w: minDims.w
						}
					});
					if(session.master) session.master.sendUTF(data);
					session.slaves.forEach(slave=>{
						if(null === slave) return;
						slave.sendUTF(data);
					});
				}
				break;
			
			case "sync_dims":
				if(role !== 'master') break;
				myDims = data.dimensions;
				session.dimensions.d.push(myDims);
				session.slaves.forEach(slave=>{
					if(null === slave) return;
					slave.sendUTF(JSON.stringify({
						action: 'request_dims'
					}));
				});
				break;
			
			case "start_session":
				session.started = true;
				broadcastSessionUpdate('Session has started.');
				break;
		}
	});
	
	connection.on('close', function(connection){
		if(!session) return;
		if(role == 'slave'){
			session.slaves[index] = null;
			broadcastSessionUpdate('Member has left session.');
			log(`Member left session: ${session.id}`);
		}else{
			session.master = null;
			session.slaves.forEach(slave=>{
				if(null === slave) return;
				slave.sendUTF(JSON.stringify({
					action: 'session_error', 
					message: 'This session has ended.'
				}));
			});
			log(`${role} left session: ${session.id}`);
			log(`${session.id} has ended`);
			delete sessions[session.id];
		}
	});
	
});