Cannot POST express error

Question

I’m trying to create a login system, follow my form:

<form action="/auth" class="login-form" method="POST">
  <h1>Login</h1>

  <div class="txtb">
    <input type="text" name="username" id="username" placeholder="Username">
  </div>

  <div class="txtb">
    <input type="password" name="password" id="password" placeholder="Password">
  </div>

  <input type="submit" class="logbtn" value="Login">

  <div class="bottom-text">
    Não ten uma conta? <a href="#">Sign up</a>
  </div>

</form>

My server.js

const http = require('http');
const express = require('express');
const socketio = require('socket.io');
const mysql = require('mysql');
const session = require('express-session');
const bodyParser = require('body-parser');
const path = require("path");

const app = express();
const server = require('http').createServer(app);
const io = require('socket.io')(server);

app.use(express.static(path.join(__dirname, 'public')));
app.set('views', path.join(__dirname, 'public'));
app.engine('html',require('ejs').renderFile);
app.set('view engine','html');

app.get('/', (req, res) => {
    res.render('index.html');
});

app.get('/chat', (req, res) => {
    res.render('chat.html');
});


let messages = [];

io.on('connection', socket => {
    console.log('Socket conectado');

    socket.on('sendMessage', data => {
        messages.push(data);
        socket.broadcast.emit('receivedMessage', data);
    });
});

//Login

var connection = mysql.createConnection({
    host:'localhost',
    user: 'root',
    password: '', 
    database: 'sanderson'
});

connection.connect(function(error) {
    if(!!error){
        console.log('Erro!')
    }
    else{
        console.log('Conectou :)')
    }
});

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

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

log.post('/auth', function(request, response) {
    var username = request.body.username;
    var password = request.body.password;
    if (username && password) {
        connection.query('SELECT * FROM user WHERE nome = ? AND senha = ?', [username, password], function(error, results, fields) {
            if (results.length > 0) {
                request.session.loggedin = true;
                request.session.username = username;
                response.redirect('public/chat.html');
            } else {
                response.send('Incorrect Username and/or Password!');
                response.redirect('public/test.html');
            }           
        });
    } else {
        response.send('Please enter Username and Password!');
        response.redirect('public/test.html');
    }
});

server.listen(3000);

My index.html is the form, when I click to send this error appears.

Answer 1

In your html you must declare the tags name and placeholder within the tag input.

Modifying your html we have the following code:

<form action="/auth" class="login-form" method="POST">
    <h1>Login</h1>

    <div class="txtb">
      <input type="text" name="username" id="username" placeholder="Username">
    </div>

    <div class="txtb">
      <input type="password" name="password" id="password" placeholder="Password">
    </div>

    <input type="submit" class="logbtn" value="Login">

    <div class="bottom-text">
      Não ten uma conta? <a href="#">Sign up</a>
    </div>

  </form>

Note that the choice of the names of these variables is not random, these are the names that are declared in your module app.js, within the post function of the route /auth , vc uses the values of these variables to query the database. Hence the declaration of these names.

It will now be possible to use your connection to the bank to verify the user and password

The code I used on my express was the following:

app js.

const express = require('express')
const path = require('path')
var log = express();

log.use(express.urlencoded({extended : true}));
log.use(express.json());

log.get('/', function(request, response) {
    response.sendFile(path.join(__dirname + '/public/index.html'));
});

log.post('/auth', function(request, response) {
    console.log(request.body)
    var username = request.body.username;
    var password = request.body.password;
    if (username && password) {
        connection.query('SELECT * FROM user WHERE nome = ? AND senha = ?', [username, password], function(error, results, fields) {
            if (results.length > 0) {
                request.session.loggedin = true;
                request.session.username = username;
                response.redirect('public/chat.html');
            } else {
                response.send('Incorrect Username and/or Password!');
                response.redirect('public/test.html');
            }           
        });
    } else {
        response.send('Please enter Username and Password!');
        response.redirect('public/test.html');
    }
});

log.listen(3000);