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How to start expressjs on shared A2hosting?

I have search a lot and I can't seem to start express js app. All I'm getting is 404 error.
Default app.js file which has http server and it works fine.
var http = require('http');
var server = http.createServer(function(req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
var message = 'It works!\n',
version = 'NodeJS ' + process.versions.node + '\n',
response = [message, version].join('\n');
res.end(response);
});
server.listen();
And this is express js code which is not working. giving me 404 error.
var express = require('express');
var app = express();
var http = require('http');
var server = http.createServer(app);
server.listen();
I also tried few other combination as well.
var express = require('express');
var app = express();
app.get('/', (req, res) => res.send('Hello World!'));
var http = require('http');
var server = http.createServer(app);
server.listen();
this one also didn't work
var express = require('express');
var app = express();
var http = require('http');
var server = http.createServer(app);
app.get('/', (req, res) => res.send('Hello World!'));
server.listen();
I also tried expressjs to create it own server and it also didn't work.
const express = require('express');
const app = express();
const port = 80;
app.get('/', (req, res) => res.send('Hello World!'));
app.listen(port, () => console.log(`Example app listening on port ${port}!`));
I also tried to remove port from app listen and not surprisingly it also didn't work.
const express = require('express');
const app = express();
app.get('/', (req, res) => res.send('Hello World!'));
app.listen();
I also tried everything from express-js-app-listen-vs-server-listen page but not successful.
This is the error I get

For others with the same A2 Hosting issue, the solution is actually so easy...
The problem with the application running the NodeJS deployment on cPanel. Phusion Passenger does not use the root path as '/', but as '/yourAppURL'. So in your NodeJS code, you have to add the specified AppURLPath to the call when using Express...
e.g.
//Instead of
app.get('/', (req, res) => res.send('Hello World!'));
//Change to
app.get('/YourSpesifiedAppURLPath/', (req, res) => res.send('Hello World!'));

How to call a socket.on() from a separated file

I'm trying to call a socket.on() event from an external .js file and I can't figure out what I'm missing...
I'm using NodeJS with ExpressJS.Below are the files:
app.js(the server file)
const fs = require('fs');
const express = require('express');
const app = express();
const http = require('http').Server(app);
var io = require('socket.io')(http);
....
//Socket Io functions
const ioObj = require( './library/io.js')(app, express, io);
// This route will be used to print the type of HTTP request the particular Route is referring to
router.use(function (req, res, next) {
console.log("/" + req.method);
next();
});
....
/library/io.js (sockets file)
module.exports = function(app, express, io){
io.on('connection', async function(socket) {
socket.on('refreshPage', function(){
console.log("page should now be refreshed !!");
socket.emit("refreshPageNow");
});
....
});
}
What I'm trying to do is to call/access the refreshPage event from /library/io.js so I can send further a "refresh webpage" signal.
I tried to do something like :
io.sockets.emit("refreshPage");
and
ioObj.sockets.emit("refreshPage");
But didn't work...

getting "Cannot GET /public/signup.html" error in express js

Very new to express and file system and don't have much idea about directories so getting this error.
var express= require('express');
var path= require('path');
var mysql= require('mysql');
var bodyParser= require('body-parser');
var app= express();
app.get('/', function(req, res) {
res.set( {
'Access-control-Allow-Origin': '*'
});
return res.redirect('/public/signup.html');
}).listen(2121);
console.log('server Running on : 2121');
app.use('/public',express.static(__dirname +"/public"));
Getting error "Cannot GET /public/signup.html"
My directories is:
-Express
--Server.js
--public
---signup.html

Looks like your code is a little jumbled up. Separate out your port listener - this should always come last. Add your routes and middleware before that as individual calls to app, and also register your get request to redirect back to your server to the signup html.
This should work:
var express = require("express");
var path = require("path");
var port = 2121;
var app = express();
// Register Middlewares/Headers
app.use((req, res, next) => {
res.header("Access-Control-Allow-Origin", "*");
next();
});
// Register Static
app.use("/public", express.static(__dirname + "/public"));
// Register redirect
app.get('/', (req, res) => {
res.redirect(req.baseUrl + '/public/signup.html');
});
app.listen(port, () => {
console.log("server Running on : ", port);
});

You're calling listen on app before you call use on your middleware and there are a few mistakes in your code. I think this should work:
app
.use('/public',express.static(`${__dirname}/public`))
.get('/', (req, res) => {
res.header({
'Access-control-Allow-Origin': '*'
});
res.redirect(`${req.baseUrl}/public/signup.html`);
})
.listen(2121);

You should provide
app.use('/public',express.static(__dirname +"/public"));
Before you using app.get
Full example:
var express= require('express');
var path= require('path');
var mysql= require('mysql');
var bodyParser= require('body-parser');
var app= express();
app.use('/public',express.static(__dirname +"/public"));
app.get('/', function(req, res) {
res.set( {
'Access-control-Allow-Origin': '*'
});
return res.redirect('/public/signup.html');
}).listen(2121);
console.log('server Running on : 2121');

Node.js freeze after a few requests

I am trying around with nodejs and socket.io
But my application refuses to work after a few requests. It takes a while and after some time it starts working again.
Here is the code for the nodejs-server, where i expect the issue.
var express = require('express');
var app = express();
var bodyParser = require('body-parser');
var sqlite3 = require('sqlite3').verbose();
var db = new sqlite3.Database('db.sqlite');
var http = require('http');
var server = http.createServer(app);
var io = require('socket.io')(server);
var port = process.env.PORT || 8080;
app.use(bodyParser.urlencoded({ extended: true }));
app.use(bodyParser.json());
var router = express.Router();
router.post('/', function (req, res) {
res.sendFile(__dirname + "/app/index.html");
});
router.get('/sample', function (req, res) {
res.sendFile(__dirname + "/app/sample.html");
});
router.post('/api/error', function (req, res) {
var data = req.body;
data.date = Date();
io.emit('error', JSON.stringify(data));
res.header("Access-Control-Allow-Origin", "*");
});
io.on('connection', function(socket){
console.log('a client connected');
});
app.use('', router);
app.use(express.static('app'));
app.use('/static', express.static('node_modules'));
// START THE SERVER
server.listen(port);
console.log('Magic happens on port ' + port);
The applikation is for monitoring errors in a full webstack.

The handler for POST /api/error isn't sending back a response, so the client will continue to wait. At some point, it may decide not to open any more connections to the server until the previous ones have been answered (or have timed out).
You can just send back a 200 response:
router.post('/api/error', function (req, res) {
var data = req.body;
data.date = Date();
io.emit('error', JSON.stringify(data));
res.header("Access-Control-Allow-Origin", "*").sendStatus(200);
});

request.body undefined after using express bodyParser

Edit: i fixed it by using:
app.configure(function(){
app.use(express.bodyParser());
});
Original post:
I'm trying to figure out how to handle a post with node and express and i'm completely stuck.
After some reading i noticed people saying i should use 'middleware' whatever that means and create a line app.use(express.bodyParser());. I assumed that after adding that i would have a req.body available in my post method. This isn't the case however. It console.log's into a undefined.
I think I don't know how to properly set this up, so here goes nothing:
var express = require('express')
, routes = require('./routes')
, user = require('./routes/user')
, http = require('http')
, path = require('path')
, UserProvider = require('./userprovider').UserProvider,
qs = require('querystring');
var userProvider = new UserProvider('localhost', 27017);
var app = express(),
server = require('http').createServer(app),
io = require('socket.io').listen(server);
server.listen(8080);
app.get('/', function (req, res) {
res.sendfile(__dirname + '/index.html');
});
app.get('/new_game', function (req, res) {
res.sendfile(__dirname + '/new_game.html');
});
app.post('/new_game', function(req, res) {
var codeToUse = Math.random()*10000;
codeToUse = Math.round(codeToUse);
console.log(req.body);
});
app.use(express.bodyParser());
app.listen(3000);

Though you've said now your code works, but i won't suggest you to use bodyParser in the options of
app.configure()
What it does is that, if you use it as you have done, any file can be send into your system for all post requests. It's better if you use
express.json()
and
express.urlencoded()
in the options of
app.configure(),
and when you expect a file use bodyParser in the respective post route like this
app.post('/upload', express.bodyParser(), function(req, res){//do something with req.files})