验证密码和用户名nodejs mysql

Question

I am working on a project and I'm trying to build a login page on nodejs-html by using mysql as database. But my code directly gets to "response.send('Please enter Username and Password!');" part, and shows me that page.(no problem with mysql connection) Why can't i check if the login username and password is right? And go to the next page if true?

var mysql = require('mysql');
var express = require('express');
var session = require('express-session');
var bodyParser = require('body-parser');
var path = require('path');

var connection = mysql.createConnection({
    ....................
});
connection.connect((err) => {
    if(err){ 
    throw err;}
   else console.log("connected");
});

var app = express();
app.use(session({
    secret: 'secret',
    resave: true,
    saveUninitialized: true
}));
app.use(bodyParser.urlencoded({extended : true}));
app.use(bodyParser.json());


app.get('/', function(request, response) {
    response.sendFile(path.join(__dirname + '/login.html'));
});

app.post('/', function(request, response) {
    var username = request.body.user_name;
    var password = request.body.pass;
    console.log(username);

    if (username && password) {
        connection.query('SELECT * FROM users WHERE user_name = ? AND pass = ?', [username, password], function(error, results, fields) {
            console.log(username);
            if (results.length > 0) {
                request.session.loggedin = true;
                request.session.user_name = username;
                response.redirect('/secondPage');
            } else {
                response.send('Incorrect Username and/or Password!');
            }           
            response.end();
        });
    } else {
        response.send('Please enter Username and Password!');
        response.end();
    }
});

app.get('/login', function(request, response) {
    if (request.session.loggedin) {
        response.send('Welcome back, ' + request.session.username + '!');
    } else {
        response.send('Please login to view this page!');
    }
    response.end();
});

app.listen(3000);

Answer 1

.body.user_name is undefined that's why 

you must have forgot name attribute in your html

input type="text" name="user_name"

also password

 <input type="password" name="pass"  >

give them suitable name atribute so that body object can access them