Nodejs and Expressjs print session out on site - node.js

Question

Hello i am trying to do a simple log in system without(password) in nodejs and expressjs, using sessions. My problem is that when I try to print the log in name on to the next page it dosent come out.
login html:
<form method="post">
<label for="">UserName:</label>
<input type="text" name="username" placeholder="Enter username" >
<input type="Submit" value="Submit">
</form>
main.html:
<h3> Welcome: <%= user %> </h3>
index.js:
var express = require('express');
var jokes = require('../model/jokes');
var session = require("express-session")
var router = express.Router();
/* GET home page. */
router.get('/', function(req, res) {
res.render('main', { title: 'Express', user: session.loggedin });
})
router.get('/login',function(req,res){
res.render('login');
})
router.get('/joke', function(req,res){
res.render('randomJoke',{ jokesObj : jokes.getRandomJoke()});
})
router.get('/allJokes', function(req,res){
res.render('Jokes',{ jokesObj1: jokes.allJokes});
})
router.get('/addNewJoke', function(req,res){
res.render('addJokes');
})
router.post('/storeJoke', function(req,res){
var funJoke = req.body;
var jsonJoke = JSON.stringify(funJoke);
jokes.addJoke(jsonJoke);
res.redirect('/addNewJoke');
})
module.exports = router;
app.js
var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var session = require("express-session");
var routes = require('./routes/index');
var users = require('./routes/users');
var app = express();
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'ejs');
// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));
app.use(session({secret:'secret_3162735',saveUninitialized:true, resave: true}));
app.use('/', routes);
app.use('/users', users);
app.use(function (req,res,next) {
var usernameLogged = req.session.loggedin;
var inputName = req.body.username;
if(usernameLogged){
return next();.
}else if(inputName){
usernameLogged = inputName;
session.userName = req.body.username;
return res.redirect("/");
}else{
req.url = "/login";
return next();
}
});
// error handlers
// catch 404 and forward to error handler
app.use(function(req, res, next) {
var err = new Error('Not Found');
err.status = 404;
next(err);
});
// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
app.use(function(err, req, res, next) {
res.status(err.status || 500);
res.render('error', {
message: err.message,
error: err
});
});
}
// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
res.status(err.status || 500);
res.render('error', {
message: err.message,
error: {}
});
});
module.exports = app;
So in main.html i cant se the user, i tried to print the session(usernameLogged) out in my main.html does not work.

Answer 1

As far as I can see it looks like your using middleware in a way it's not really supposed to be used. Middleware in Express is normally used to do an action for every (or a sub-section) of requests e.g logging, setting custom headers and so on, you can read more about Express-middleware from the documentation.
You need to have a route to respond to POST requests (which your login form should send):
Firstly, your login template needs to send the form input to /login like so:
<form method="post" action="/login">
<label for="">UserName:</label>
<input type="text" name="username" placeholder="Enter username" >
<input type="Submit" value="Submit">
</form>
To display the form you have a route like so to simply render the login template:
router.get('/login', function(req, res) {
// Show the login form
res.render('login');
})
Finally, you should have a route to accept the user-input from the form. As the form sends a POST request, you need to use router.post:
router.post('/login', function(req, res) {
if (req.session.loggedin) {
// User is already logged in, send them to the main page
return res.redirect('/')
}
else if (req.body.username) {
// User is not logged in, set the username for the user's session
req.session.userName = req.body.username;
// Then redirect to the main page
return res.redirect('/')
}
else {
// No username was entered
res.send('Please enter a username')
}
})
And finally,
You then should be safe to delete your middleware (the app.use section) of your app.js file.
Edit:
A user correctly spotted that questions (and answers) were using session rather than using req.session - Session refers to the express-session module, whereas req.session refers to the user's session.
So your '/' route should look like this:
res.render('main', { title: 'Express', user: req.session.loggedin });
If you want to show if the user is logged in or not.
Or you can do the following to show the current user's username.
res.render('main', { title: 'Express', user: req.session.userName });