socket.js

/**
 * Code for implementing Socket.io to enable real time tracking of user 
 * connections
 * 
 * Primary reference for capturing session data through web sockets
 * https://github.com/websockets/ws/blob/master/examples/express-session-parse/index.js
 */

const pool = require('./util/db')
const sess = require('./util/session')

module.exports = (io) => {
    io.use(function (socket, next) {
        sess(socket.request, socket.request.res || {}, next);
    });
    
    // Handle new web socket connection
    io.on('connection', (socket) => {
        socket.on('connect-admin', () => {
            socket.join('admin')
        })
    
        // console.log(io.sockets.adapter.rooms.get('user').size)
    
        console.log(`Connected. Here is the session`)
        let session = socket.request.session
        console.log(session)
    
        socket.on('new user', (data) => {
            // Assign user to either group A or B
            let assignGroup = (min, max) => {
                let num = Math.random() * (max - min) + min;
    
                return Math.round(num);
            };
    
            // Student's web socket will join current assessment and group to be assigned if doing the training section
            let room = data.assessment === 'training' ? data.assessment + (assignGroup(1, 2) == 1 ? "A" : "B") : data.assessment
            socket.join(room)
    
            io.to("admin").emit("new user", {
                student_id: session.student_id,
                username: data.username,
                // username: session.username,
                current_test: data.assessment,
                date_joined: data.joined
            });
    
            // Create new entry in 'active_connections' table in database
            pool.query(`
        INSERT INTO active_connections (session_id, student_id, username, current_test, date_joined)
        VALUES ($1, $2, $3, $4, $5)
        ON CONFLICT (session_id) DO NOTHING`, [
                session.id,
                session.student_id,
                data.username,
                // session.username,
                data.assessment,
                data.joined
            ], (err, result) => {
                if (err) throw err;
            })
        })
    
        // Upon receiving unlock request, emit unlock event to all connected student sockets and
        // attach event info
        socket.on('unlock training', (configInfo) => {
            io.to('trainingA').emit('unlock training', configInfo, "A")
            io.to('trainingB').emit('unlock training', configInfo, "B")
        })
    
        socket.on('unlock testing1', (configInfo) => {
            io.to("testing1").emit('unlock testing1', configInfo)
        })
    
        socket.on('unlock testing2', (configInfo) => {
            io.to("testing2").emit('unlock testing2', configInfo)
        })
    
        socket.on('unlock rating', (configInfo) => {
            io.to('rating').emit('unlock rating', configInfo)
        })
    
        socket.on('unlock 2AFC', (configInfo) => {
            io.to('2AFC').emit('unlock 2AFC', configInfo)
        })
    
        // Remove disconnected user from database
        socket.on('disconnecting', () => {
            let [, room] = socket.rooms
            console.log(`Disconnected. Socket has left ${room}`)
    
            io.to("admin").emit('remove user', {
                id: session.student_id,
                current_test: room
            })
    
            pool.query("UPDATE active_connections SET date_disconnected=$1 WHERE session_id=$2", [
                new Date().toLocaleString(),
                session.id
            ], (err, result) => {
                if (err) throw err;
            })
        })
    });
}