sockets.js

const _ = require('lodash');
const cookie = require('cookie');
const sessionDB = require('./utils').redis;
const settings = require('./utils').settings;
const io = require('socket.io')(settings.general.socket);
const app = require('./app').app;
const Generators = app.get('Generators');

const Snippet = require('./models/Snippet');
const Version = require('./models/Version');

const abuseLimit = 20;
let abuseCache = {};
let timeout = {};

function checkAbuse(id) {
 // abuse is considered <abuseLimit> requests per second from same socket
 // Block further requests until until 5 seconds have passed without another barrage

 if (!(id in abuseCache)) {
 abuseCache[id] = {
 firstAccess: new Date().getTime(),
 lastAccess: new Date().getTime(),
 total: 1
 };

 // Update current stats
 } else {
 abuseCache[id].lastAccess = new Date().getTime();
 abuseCache[id].total++;
 }

 // Check for abuse
 if (abuseCache[id] && abuseCache[id].total > abuseLimit && abuseCache[id].lastAccess - abuseCache[id].firstAccess < 1000) {
 timeout[id] = new Date().getTime(); // time they were placed into time out
 return true;
 }

 if (id in timeout) {
 return true;
 }
 return false;
}

function checkTimeout() {
 _.each(timeout, (a, b) => {
 if (new Date().getTime() - a > 1000) {
 delete timeout[b];
 }
 });
}

// Reset abuse cache every second
setInterval(() => {
 abuseCache = {};
}, 1000);

setInterval(checkTimeout, 2500);

// Attach the user's session to the socket object
// If user isn't logged in, set session to null for front page demo
io.use((socket, next) => {
 let data = socket.handshake || socket.request;
 try {
 let sessionID = cookie.parse(data.headers.cookie)[settings.session.key].slice(2, 34);
 sessionDB.get('sess:' + sessionID, (err, session) => {
 if (err) console.log(err);
 socket.session = session;
 next();
 });
 } catch(e) {
 socket.session = null;
 next();
 }
});

io.on('connection', socket => {

 // Search
 socket.on('search', msg => {
 if (checkAbuse(socket.id)) return socket.emit('abuse');

 let tags = _.uniq(msg.query.slice(0, 255).split(',').map(tag => tag.trim()).filter(tag => tag !== "")).filter(tag => tag.match(/^([a-zA-Z0-9 _\-\.+\[\]\{\}\(\)]{1,32})$/g) !== null);
 Snippet.search(tags).then(data => {
 let obj = data.reduce(function(o, v, i) {
 o[v.id] = v;
 return o;
 }, {});
 socket.emit('searchResults', obj);
 });
 });

 // Snippet info
 socket.on('snippet', msg => {
 if (checkAbuse(socket.id)) return socket.emit('abuse');

 Version.getCond({snippetID: msg.id}).then(snippet => {
 Snippet.getCond({['s.id']: snippet.snippetID}).then(orig => {
 if (snippet === null) {
 socket.emit('snippetResults', null);
 } else if (snippet.published === 0) {
 Version.getVersion(orig.ref, snippet.version-1).then(ver => {
 socket.emit('snippetResults', ver)
 });
 } else {
 socket.emit('snippetResults', snippet)
 }
 });
 });
 });

 // Generators
 socket.on('lintCode', msg => {
 if (checkAbuse(socket.id)) return socket.emit('abuse');

 msg.code = String(msg.code).slice(0, 8192);
 let shortest = Math.floor(Math.random() * Generators.realtime.length);
 for (let i = 0; i < Generators.realtime.length; i++) {
 if (Generators.realtime[i].queueLength() < Generators.realtime[shortest].queueLength()) {
 shortest = i;
 }
 }

 // Check if chosen Generator has crashed and is in middle of restarting
 if (!Generators.realtime[shortest].generator.connected) {
 socket.emit('codeLinted', {error: {formatted: "Something bad has happened...please try again later."}, results: [], fmt: null});
 } else {
 // Don't pass along ref/owner info if from front page demo
 if (JSON.parse(socket.session).loggedin === undefined) {
 Generators.realtime[shortest].queue.push({socket, data: {src: msg.code, ref: null, owner: 'demo', type: 'lint'}});
 } else {
 Generators.realtime[shortest].queue.push({socket, data: {src: msg.code, ref: msg.ref, owner: JSON.parse(socket.session).user, type: 'lint', uri: msg.uri}});
 }
 }
 });

 socket.on('lintDemoCode', msg => {
 if (checkAbuse(socket.id)) return socket.emit('abuse');

 msg.code = String(msg.code).slice(0, 8192);
 let shortest = Math.floor(Math.random() * Generators.demo.length);
 for (let i = 0; i < Generators.demo.length; i++) {
 if (Generators.demo[i].queueLength() < Generators.demo[shortest].queueLength()) {
 shortest = i;
 }
 }

 // Check if chosen Generator has crashed and is in middle of restarting
 if (!Generators.demo[shortest].generator.connected) {
 socket.emit('codeLinted', {error: {formatted: "Something bad has happened...please try again later."}, results: [], fmt: null});
 } else {
 // Don't pass along ref/owner info if from front page demo
 if (JSON.parse(socket.session).loggedin === undefined) {
 Generators.demo[shortest].queue.push({socket, data: {src: msg.code, ref: null, owner: 'demo', type: 'demo'}});
 } else {
 Generators.demo[shortest].queue.push({socket, data: {src: msg.code, ref: msg.ref, owner: JSON.parse(socket.session).user, type: 'demo'}});
 }
 }
 });

 socket.on('lintSnippetCode', msg => {
 if (checkAbuse(socket.id)) return socket.emit('abuse');

 msg.code = String(msg.code).slice(0, 8192);
 let shortest = Math.floor(Math.random() * Generators.realtime.length);
 for (let i = 0; i < Generators.realtime.length; i++) {
 if (Generators.realtime[i].queueLength() < Generators.realtime[shortest].queueLength()) {
 shortest = i;
 }
 }

 // Check if chosen Generator has crashed and is in middle of restarting
 if (!Generators.realtime[shortest].generator.connected) {
 socket.emit('codeLinted', {error: {formatted: "Something bad has happened...please try again later."}, results: [], fmt: null});
 } else {
 // Don't pass along ref/owner info if from front page demo
 if (JSON.parse(socket.session).loggedin === undefined) {
 Generators.realtime[shortest].queue.push({socket, data: {src: msg.code, ref: null, owner: 'demo', type: 'snippet'}});
 } else {
 Generators.realtime[shortest].queue.push({socket, data: {src: msg.code, ref: msg.ref, owner: JSON.parse(socket.session).user, type: 'snippet'}});
 }
 }
 });
});

module.exports = io;