Develop Reference

Node.js connection error server is running but page is not loading

The server is running without any errors. but the page is constantly loading and stays on. Then I get the error 'Incomplete response received from application.
Console Img
App.js
const express = require('express')
const exphbs = require('express-handlebars')
const app = express()
const hostname = '127.0.0.1'
const port = process.env.PORT || 3000
const mongoose = require('mongoose')
const mongo = require('mongodb')
const bodyParser = require('body-parser')
const fileUpload = require('express-fileupload')
const expressSession = require('express-session')
const connectMongo = require('connect-mongo')
const methodOverride = require('method-override')
const limit = require('./helpers/limit').limit
const truncate = require('./helpers/truncate').truncate
const paginate = require('./helpers/paginate').paginate
const { MongoClient, ServerApiVersion } = require('mongodb');
const uri = "mongodb+srv://siber_haber:myapppass#siberhabercomm.sspd3.mongodb.net/Siberhabercomm?retryWrites=true&w=majority";
const client = new MongoClient(uri, { useNewUrlParser: true, useUnifiedTopology: true, serverApi: ServerApiVersion.v1 });
client.connect(err => {
const collection = client.db("test").collection("devices");
// perform actions on the collection object
client.close();
});
const mongoStore = connectMongo(expressSession)
app.use(expressSession({
secret: 'testo test',
resave: false,
saveUninitialized: true,
store: new mongoStore({ mongooseConnection: mongoose.connection })
}))
app.use(fileUpload())
app.use(express.static('public'))
app.use(methodOverride('_method'))
// handle-bars helpers
const hbs = exphbs.create({
helpers: {
limit: limit,
truncate: truncate,
paginate: paginate
}
})
app.engine('handlebars', hbs.engine)
app.set('view engine', 'handlebars')
app.use(bodyParser.urlencoded({ extended: false }))
app.use(bodyParser.json())
// DISPLAY LINK MIDDLEWARE
app.use((req, res, next) => {
const {userId} = req.session
if(userId) {
res.locals = {
displayLink : true
}
} else {
res.locals = {
displayLink : false
}
}
next()
})
app.use((req, res, next) => {
res.locals.sessionFlash = req.session.sessionFlash
delete req.session.sessionFlash
next()
})
const main = require('./routes/main')
const post = require('./routes/posts')
const users = require('./routes/users')
const admin = require('./routes/admin/index')
app.use('/', main)
app.use('/posts', post)
app.use('/users', users)
app.use('/admin', admin)
app.listen(port, hostname, () => {
console.log(` Server Çalışıyor http://${hostname}:${port}`)
})
Please help me understand where the error is
i think the error is from the database code. i'm not so sure.
Node version v10.24.1

Global variable doesn't work on node.js server

I have simple javascript code and I don't understand why each time globalString is zero. Even after I call high. It should be global variable which will be same between method calls.
const express = require('express');
const { exec } = require('child_process');
const bodyParser = require('body-parser');
const cors = require('cors');
const fs = require('fs');
const app = express();
app.use(cors());
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
var test_out = "";
var globalString = 0;
app.post('/high', (req, res) => {
globalString = 1;
return res.status(200).json({ result: 'ok' , message: globalString.toString() });
});
app.post('/low', (req, res) => {
globalString = 0;
return res.status(200).json({ result: 'ok' , message: globalString.toString() });
});
app.post('/state', (req, res) => {
globalString = 0;
return res.status(200).json({ result: 'ok' , message: globalString.toString() });
});
app.listen(4000, () => console.log('Server is up.'));

As suggested in above comment " you are setting globalString 0 every time api get called"
const express = require('express');
const { exec } = require('child_process');
const bodyParser = require('body-parser');
const cors = require('cors');
const fs = require('fs');
const app = express();
app.use(cors());
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
var test_out = "";
var globalString = 0;
app.post('/high', (req, res) => {
globalString = 1;
return res.status(200).json({ result: 'ok' , message: globalString.toString() });
});
app.post('/low', (req, res) => {
//globalString = 0; you are setting globalString 0 every time this api get called
return res.status(200).json({ result: 'ok' , message: globalString.toString() });
});
app.post('/state', (req, res) => {
//globalString = 0; you are setting globalString 0 every time this api get called
return res.status(200).json({ result: 'ok' , message: globalString.toString() });
});
app.listen(4000, () => console.log('Server is up.'));

cant receive payload from post method in expressJS

hello im using express for server everything is working find but i am not receiving my data from post method.Iam using body-parser too
const express = require("express")
const app = express()
var bodyParser = require('body-parser')
app.use(bodyParser.urlencoded({ extended: false }))
app.use(bodyParser.json())
app.post("/signup", (req,res)=>{
var data = req.body
res.send(req.body)
})

Here is a 100% working code. If it doesn’t work, then tell me how do you make a POST request?
const express = require("express")
const app = express()
const bodyParser = require('body-parser')
app.use(bodyParser.urlencoded({ extended: false }))
app.use(bodyParser.json())
app.post("/signup", (req, res) => {
var data = req.body
console.log(data)
res.send(req.body)
})
app.listen(3000)
Front-end:
axios.post('http://localhost:3000/signup', {
firstName: 'Fred',
lastName: 'Flintstone'
})
.then(function (response) {
console.log(response);
})
.catch(function (error) {
console.log(error);
});

Express rest api and mongoDB lowercase query

I've created simple Express.js Rest API with MongoDB. I am using this package: https://www.npmjs.com/package/api-query-params and everything works very well except for one thing. I have a URL like this:
localhost/properties/?town=LONDON
this returns all properties from London, the problem is with this is the next thing, I need to put capitalize value (LONDON), I am trying to achieve that this value can be lowercase (london), so final URL will be like this:
localhost/properties/?town=london
My route:
const express = require('express');
const router = express.Router();
const Property = require('../models/Property');
const aqp = require ('api-query-params');
router.get('/all', (req, res, next) => {
const { filter, skip, limit, sort, projection, population, casters } = aqp(req.query, {
casters: {
lowercase: val => req.query.toLowerCase(),
},
});
Property.find(filter)
.skip(skip)
.limit(limit)
.sort(sort)
.select(projection)
.populate(population)
.exec((err, properties) => {
if (err) {
return next(err);
}
res.send(properties);
});
});
module.exports = router;
And app.js
const express = require('express');
const app = express();
const bodyParser = require("body-parser");
require('dotenv/config');
const mongoose = require('mongoose');
const propertyRoute = require('./routes/property');
const PORT = process.env.PORT || 3000;
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
app.use('/properties', propertyRoute);
//routes
app.get('/', (req, res) => {
res.send('value');
});
mongoose.connect('linkdatabse', {
newUrlParser: true,
})
app.listen(PORT, () => {
console.log(`Server started on port ${PORT}`);
});
I've updated my route according to documentation: https://www.npmjs.com/package/api-query-params#add-custom-casting-functions
but still, this doesn't work
Can anybody try to help me with this, what am I doing wrong?

Sending data on server by fetch

Can someone explain to me why after sending a request, server returns POST {} {}- I mean empty objects?
I don't know where this data is. Why did it dissapear?
I have no idea how to solve it...
index.js:
window.addEventListener("DOMContentLoaded", () => {
const form = document.querySelector("form");
form.addEventListener("submit", event => {
console.log("włącza sie");
event.preventDefault();
const name = document.getElementById("name").value;
const password = document.getElementById("password").value;
fetch("http:localhost:3000/register", {
method: "POST",
body: JSON.stringify({ name, password })
})
.then(res => {
console.log(res);
})
.catch(error => console.log(error));
});
});
//server.js:
const http = require("http");
const app = require("./app");
const port = 3000;
const server = http.createServer(app);
server.listen(port, () => {
console.log("server włączony");
});
//app.js
const loginRoute = require("./api/routes/loginRoute");
const registerRoute = require("./api/routes/registerRoute");
const verify = require("./autorization/verify");
app.use(bodyParser.urlencoded({ extended: true }));
app.use(bodyParser.json());
app.use("/", (req, res, next) => {
console.log(req.method, req.query, req.body);
next();
});
app.use("/", loginRoute);
app.use("/", registerRoute);
app.use(verify);

based from your screenshot, there's a CORS issue. You can overcome that using
https://github.com/expressjs/cors middleware
var cors = require('cors');
app.use(cors());
or enable CORS for the specific route only
app.use('/', cors(), registerRoute);

registerRoute:
const express = require('express');
const router = express.Router();
const register = require('../../mongo/register');
router.post('/register',register);
module.exports = router;
register.js:
const mongo = require('./database');
const User = require('../api/patterns/user');
const register = (req,res)=>{
const toSave = new User(req.body);
User.findOne({name: req.body.name},(err,name)=>{
if(err) throw err;
if(!name){
toSave.save( (err)=> {
if (err) throw err;
console.log('user zapisany');
});
}else{
console.log('juz taki istnieje');
}
});
};
app.js:
const loginRoute = require('./api/routes/loginRoute');
const registerRoute = require('./api/routes/registerRoute');
const verify = require('./autorization/verify');
var cors = require('cors');
app.use(cors());
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
app.use(bodyParser.json());
app.use('/', (req,res,next)=>{console.log(req.method, req.query, req.body);
next();});
app.use('/', loginRoute);
app.use('/', registerRoute);
app.use(verify);
module.exports = app;
It still returns empty objects :(