server.js

var request = require('request');
var cheerio = require('cheerio');
var resString = null;
var nodemailer = require('nodemailer');
var express  = require('express');
var fs = require('fs');
var app = express();
require('dotenv').config();

const sgMail = require('@sendgrid/mail');
sgMail.setApiKey(process.env.SENDGRID_API_KEY);


var mailOptions = {
	from: 'automated.nikhilyadav3000@gmail.com',
	to: 'nikhilyadav3000@gmail.com',
	subject: 'Result Notification'
};




app.get('/',function(req,res){

		fs.readFile('index.html',null,function(error,data){
		if(error)
		{
			console.log('error');
			
		}
		else {
			console.log('no error in loading index.html');
			res.write(data);
		}
	});
		
		
	request('http://exam.dtu.ac.in/result.htm',function(err,response,html){
					if(!err && response.statusCode == 200)
					{
						console.log('inside if');
						var $ = cheerio.load(html);
						$('#AutoNumber1').filter(function(){
							var data = $(this);
							var title = data.children().children().eq(2).children().next().children().text();
							console.log(title);
							resString = title;
						});
					}
				});

		setInterval(function(){
		console.log('inside while ');
				request('http://exam.dtu.ac.in/result.htm',function(err,response,html){
					if(!err && response.statusCode == 200)
					{
						console.log('inside if');
						var $ = cheerio.load(html);
						$('#AutoNumber1').filter(function(){
							var data = $(this);
							var title = data.children().children().eq(2).children().next().children().text();
							console.log(title);
							if(!title.includes(resString))
							{
								console.log("declared");
								mailOptions.text = 'result of ' + title + 'declared';
								sgMail.send(mailOptions, function (err, info) {
									if (err) {
										console.log(err.response.body);
										return 'err';
									}
									else {
										console.log(info.response);
										return 'success';
									}
								});
							
							}
							
							else
							console.log("not declared");

							resString = title;				
						});
					}
					else
					{
						console.log('else');
					}
				});
			},30000);


});

var port = process.env.PORT || 5000;

app.listen(port,function()
{
	console.log('server started at port '+port);
});