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How to split and export the mysql code into other file and can be use anywhere in Reactjs

I'm new in Reactjs. Its been 2 months since I learned Reactjs. I have a question. How to split the mysql code that i created into 2 file and can be call it anywhere. Here i attached the mysql code.
const express = require('express');
const app = express();
const mysql = require('mysql');
const cors = require('cors');
const { response } = require('express');
app.use(cors());
app.use(express.json()); //convert from json
// configure database
const db = mysql.createConnection({
user: 'root',
host: 'localhost',
password: '',
database: 'testdb',
});
// declare function
function getQuery(db, sqlQuery, res) {
db.query(sqlQuery, (err, result) => {
if (err) {
res.send(err.sqlMessage);
} else {
res.send(result);
}
});
}
function setQuery(db, sqlQuery, par, res) {
db.query(sqlQuery, par, (err, result) => {
if (err) {
res.send(err);
} else {
res.send(result);
}
});
}
// configure server port number
const listener = app.listen(process.env.PORT || 3333, () => {
console.log('App is listening on port ' + listener.address().port)
})
// call function
app.get("/users", (req, res) => {
getQuery(db, displayTableQuery, res)
});
app.post("/", (req, res) => {
const RegisterUserQuery = "INSERT INTO users set ?";
const par = req.body;
setQuery(db, RegisterUserQuery, par, res)
});
The code i want to be in other file:
// call function
app.get("/users", (req, res) => {
getQuery(db, displayTableQuery, res)
});
app.post("/", (req, res) => {
const RegisterUserQuery = "INSERT INTO users set ?";
const par = req.body;
setQuery(db, RegisterUserQuery, par, res)
});
How to make the code above in other file so that i can make it globally use for other person in the project. Thank you so much for your time. Hope you guys can help me :(

Create other file, example mysqlDatabase.js. And write in that file :
// configure database
const db = mysql.createConnection({
user: 'root',
host: 'localhost',
password: '',
database: 'testdb',
});
module.exports = db
Then to access in other file, use require and write function without db as argument :
const db = require('./mysqlDatabase.js')
// declare function
function getQuery(sqlQuery, res) {
db.query(sqlQuery, (err, result) => {
if (err) {
res.send(err.sqlMessage);
} else {
res.send(result);
}
});
}
function setQuery(sqlQuery, par, res) {
db.query(sqlQuery, par, (err, result) => {
if (err) {
res.send(err);
} else {
res.send(result);
}
});
}

Can't Query MySQL Database from Express Route

I can't figure out how to query the MySQL database from the promise in my route file. I'm writing a RESTful API to query a MySQL database with GET methods. I'm using Express and Axios for Javascript promises.
I want to get back the list of books from a SQL table and the count of how many listings in the returned JSON.
server.js
const http = require('http');
const app = require('./app');
const port = process.env.PORT || 3000;
const server = http.createServer(app);
server.listen(port);
app.js
const express = require('express');
const app = express();
const morgan = require('morgan');
const bodyParser = require('body-parser');
const mysql = require('mysql');
const bookRoutes = require('./api/routes/books');
const entryRoutes = require('./api/routes/entries');
const connection = mysql.createConnection({
host: 'localhost',
user: 'rlreader',
password: process.env.MYSQL_DB_PW,
database: 'books'
});
app.use(morgan('dev'));
app.use(bodyParser.urlencoded({extended: false}));
app.use(bodyParser.json());
app.use((req, res, next) => {
res.header('Access-Control-Allow-Origin', '*');
res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept, Authorization');
if (req.method === 'OPTIONS') {
res.header('Access-Control-Allow-Methods', 'GET');
return res.status(200).json({});
}
next();
});
// Routes which should handle requests
app.use('/books', bookRoutes);
app.use('/entries', entryRoutes);
app.use((req, res, next) => { //request, response, next
const error = new Error('Not found');
error.status = 404;
next(error);
});
app.use((error, req, res, next) => {
res.status(error.status || 500);
res.json({
error: {
message: error.message
}
});
});
module.exports = app;
books.js
const express = require('express');
const router = express.Router();
const axios = require('axios');
//do I import something for mysql here?
router.get('/', (req, res, next) => {
axios.get('/').then(docs => {
res.status(200).json({
"hello": "hi" //want to query MySQL database here
})
}).catch(err => {
res.status(500).json({
error: err
});
})
});
module.exports = router;
Any help would be appreciated. For starters, how do I get const connection from app.js to books.js?

I moved the code connecting to the MySQL database to a separate file and included that:
const con = require('../../db');
Next, I had to properly return the response:
router.get('/', (req, res, next) => {
let responseData = axios.get('/').then(docs => {
const sql = "SELECT title, id FROM books";
con.query(sql, function (err, result) {
if (err) {
console.log("error happened");
}
return res.status(200).json(result);
});
}).catch(err => {
res.status(500).json({
error: err
});
});
});

How can I split server.js in the right way?

I am writing my own app (both of back and frontend). I want to ask you guys if I am doing it in the right way.
I want to split server.js to a few files (in PHP I would use include() for it) but I am not sure if it is the right way.
Here is some code example:
const app = require('express')(),
fs = require('fs'),
http = require('http').Server(app),
io = require('socket.io')(https),
path = require('path'),
login_user = require('./routes/login_user'),
add_user = require('./routes/add_user'),
logout = require('./routes/logout');
app.post('/login_user', (req, res, next) => {
login_user.go(req, res, next);
});
app.post('/add_user', (req, res) => {
add_user.go(req, res);
});
app.get('/logout', (req, res) => {
logout.go(req, res);
});
Please note that's not the whole code and I want to focus on spliting "routes" or "paths" to a few files. For example a whole API login system is in /routes/login_user.js file (exported).
Now I have got so many paths and code is looking a little bit weird.
app.post('/check_balance', (req, res) => {
check_balance.go(req, res);
});
app.post('/add_incoming', (req, res) => {
add_incoming.go(req, res);
});
app.post('/add_outgoing', (req, res) => {
add_outgoing.go(req, res);
});
app.post('/add_category', (req, res) => {
add_category.go(req, res);
});
app.post('/change_settings', (req, res) => {
change_settings.go(req, res);
});
app.post('/login_user', (req, res, next) => {
login_user.go(req, res, next);
});
app.post('/add_user', (req, res) => {
add_user.go(req, res);
});
app.post('/verify_user', (req, res) => {
verify_user.go(req, res);
});
app.get('/logout', (req, res) => {
logout.go(req, res);
});
app.get('/check_settings', (req, res) => {
check_settings.go(req, res);
});
app.get('/check_categories', (req, res) => {
check_categories.go(req, res);
});
app.post('/remove_categories', (req, res) => {
remove_categories.go(req, res);
});
app.get('/check_incomings', (req, res) => {
check_incomings.go(req, res);
});
app.get('/check_outgoings', (req, res) => {
check_outgoings.go(req, res);
});
app.get('/check_both', (req, res) => {
check_both.go(req, res);
});
app.get('/check_outgoings_chart', (req, res) => {
check_outgoings_chart.go(req, res);
});
app.get('/check_incomings_chart', (req, res) => {
check_incomings_chart.go(req, res);
});
app.post('/remove_incomings', (req, res) => {
remove_incomings.go(req, res);
});
app.post('/remove_outgoings', (req, res) => {
remove_outgoings.go(req, res);
});

Make your server.js as simple as possible and extract all your routing logic to separate folder (possibly name it "routes"). If you also want to define yours schema, put it in separate folder ("models"). A complete solution can be like this:
in Model Folder:
user.js
const mongoose = require("mongoose"); // In case if you want to use MongoDB
const userSchema = new mongoose.Schema({
name: { type: String, required:true },
email: { type: String, required: true },
password: { type: String, required: true },
});
exports.User = User;
In routes folder:
users.js
const { User } = require("../models/user");
const router = express.Router();
//define your routes here
router.get('/', async(req,res)=>{
const users = await User.find();
res.send(users)
});
module.exports = router;
And finally in your server.js
const app = require('express')(),
fs = require('fs'),
http = require('http').Server(app),
io = require('socket.io')(https),
path = require('path'),
users = require('./routes/users');
app.use("/api/users", users); //With this API Endpoint you can access it like http://{your_domain}/api/users
If you want to make it more clean, you can wrap all routing paths to another folder. Lets call it "startup".
with this you can do like this.
in your startup folder:
routes.js
const users = require("../routes/users");
module.exports = function(app) {
app.use("/api/users", users);
//add all routes here
}
Then in your server.js
require("./startup/routes")(app); //all routes will be imported

I think this is what you need.
Let's say that there is a file called routers/login.js:
var express = require('express');
var router = express.Router();
router.get('/login', function(req, res) {
// do something
});
then app.js:
...
var login = require('./routes/login');
app.use("/login", login)

Put all the routes files in a folder with multiple files like User_routes.js can contain routes related to user and so on.
Also all you need to then is to export these routes from each file by using module.export.your_module and include them in your server file like in user routes :
// Login Page
router.get('/login', (req, res) => res.render('login'));
// Register Page
router.get('/register',(req, res) => {
res.render('register'); });
then import it as
module.exports = router;
also include it as :
app.use('/users', require('./routes/users.js'));
app.use('/',(req,res,next)=>{
console.log('I should handle it Now.');
res.render('404');
});

When I make a GET request to NodeJS it doesn't run the code in the route

I am trying to make a get request with ajax, it doesn't seem to run the code in my NodeJS /tools route, maybe someone can enlighten me. I am looking to run a script from nodeJS from an AJAX request. xhr GET request doesn't seem to work with to initiate the that console log in the nodejs route.
These are my routes.
const express = require('express');
const router = express.Router();
const User = require('../models/user.js');
const mid = require('../middleware');
const axios = require('axios');
// Home Routes
router.get('/', (req, res, next) => {
res.render('index');
});
// About Routes
router.get('/about', (req, res, next) => {
res.render('about', {title : '| About'});
});
// Tools Routes
router.get('/tools', (req, res, next) => {
console.log("ajax request went through!");
});
router.post('/tools', (req, res, next) => {
var domain = req.body.domain;
canYouDigIt(domain);
});
router.get('/map', (req, res, next) => {
res.render('map');
});
// Login Routes
router.get('/login', mid.loggedOut, (req, res, next) => {
res.render('login', {title : '| Log in'});
});
router.post('/login', (req, res, next) => {
if ( req.body.email && req.body.password) {
User.authenticate(req.body.email, req.body.password, function(error, user){
if (error || !user) {
var err =new Error('Wrong email or password.');
err.status = 401;
return next(err);
} else {
req.session.userId = user._id;
return res.redirect('/profile');
}
});
} else {
var err =new Error('Email and password are required!');
err.status = 401;
return next(err);
}
});
// Logout Routes
router.get('/logout', (req, res, next) => {
if (req.session){
// Delete Session
req.session.destroy(function(err) {
if(err) {
return next(err);
} else {
return res.redirect('/');
}
});
}
});
// Registration Routes
router.get('/registration', mid.loggedOut, (req, res, next) => {
res.render('registration', {title : '| Registration'});
});
router.post('/registration', (req, res, next) => {
// Check if all fields are filled
if (req.body.userName && req.body.password && req.body.confirmPassword && req.body.firstName && req.body.lastName && req.body.email) {
// Confirm Password is the same
if ( req.body.password != req.body.confirmPassword) {
const err = new Error ("Passwords don't match!");
err.status = 400;
return next(err);
};
const userData = {
userName: req.body.userName,
password: req.body.password,
firstName: req.body.firstName,
lastName: req.body.lastName,
email: req.body.email
};
// Use schema 'create' method to insert document into Mongo
User.create(userData, (error, user) => {
if (error) {
return next(error);
} else {
req.session.userId = user._id;
return res.redirect('/profile');
}
});
} else {
const err = new Error("All Fields Required.");
err.status = 400;
return next(err);
}
});
module.exports = router;
This is my html/pug calling the route
section(id="digToolWrapper")
form( id="digToolInput" )
ul
li #[input(id="digTool" name="domain" type="text" placeholder="Can you dig it?")]#[input(id="whois" value="whois" type="button" onclick="digIt()")]
This is my ajax request
function digIt() {
var xhr = new XMLHttpRequest();
var domain = document.getElementById("digTool").value;
xhr.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
console.log(domain);
}
};
xhr.open('GET', '/tools', true);
console.log(domain);
xhr.send();
};
App.js file
const express = require('express');
const session = require('express-session');
const bodyParser = require('body-parser');
const cookieParser = require('cookie-parser');
const path = require('path');
const mongoose = require('mongoose');
const MongoStore = require('connect-mongo')(session);
const axios = require('axios');
const app = express();
// Mongodb connection
mongoose.connect("mongodb://localhost:27017/nymadic", { useNewUrlParser: true });
const db = mongoose.connection
// Mongo error
db.on('error', console.error.bind(console, 'connection error:'));
// Use sessions for tracking logins
app.use(session({
secret: 'keyboard cat!',
resave: true,
saveUninitialized: false,
// This stores sessions in the Mongo DB so the server doesnt become overloaded
store: new MongoStore({
mongooseConnection: db
})
}));
// Make user ID available in template
app.use(function (req, res, next){
res.locals.currentUser = req.session.userId;
next();
});
// Body Parser and Cookie Parser
app.use(bodyParser.urlencoded({ extended:false }));
app.use(cookieParser());
// Static Files
app.use(express.static(__dirname + '/public'));
// Pug Render Engine
app.set('view engine', 'pug');
// Routes
const mainRoutes = require('./routes');
const profileRoutes = require('./routes/profile');
const wikiRoutes = require('./routes/wiki');
app.use(mainRoutes);
app.use('/profile', profileRoutes);
app.use('/wiki', wikiRoutes);
app.listen(8080, () => {
console.log('Nodejs is running on port 8080...');
});

Access req.user to save id to mongoDB

I'm currently having an issue with figuring out how I can access req.user so I can get the logged in users id and save it with the items that they save on the web page. That way when they load the web page they only get their items. The only place I know where I have access to req.user is in my /router/auth.js file. I want to figure out a way to access it in a different router file.
router/auth.js
const express = require('express');
const passport = require('passport');
const bodyParser = require('body-parser');
const jwt = require('jsonwebtoken');
const config = require('../config');
const router = express.Router();
const createAuthToken = function (user) {
return jwt.sign({ user }, config.JWT_SECRET, {
subject: user.username,
expiresIn: config.JWT_EXPIRY,
algorithm: 'HS256'
});
};
const localAuth = passport.authenticate('local', { session: false });
router.use(bodyParser.json());
router.post('/login', localAuth, (req, res) => {
const authToken = createAuthToken(req.user.serialize());
res.json({ authToken });
});
const jwtAuth = passport.authenticate('jwt', { session: false });
router.post('/refresh', jwtAuth, (req, res) => {
const authToken = createAuthToken(req.user);
res.json({ authToken });
});
/router/portfolio.js
router.post('/:id', (req, res) => {
const id = req.params.id;
const { holdings } = req.body;
CryptoPortfolio.findOne({ id }, (err, existingCoin) => {
if (existingCoin === null) {
getCoins(id)
.then(x => x[0])
.then(value =>
CryptoPortfolio.create({
id: value.id,
holdings,
_creator: this is where I want to add req.user.id
}).then(() => value))
.then(newItem => {
res.status(201).json(newItem);
})
.catch(err => {
console.error(err);
res.status(500).json({ message: 'Internal server error' });
});
} else {
const capitalizedId = id.charAt(0).toUpperCase() + id.slice(1);
res.json(`${capitalizedId} already in watchlist`);
}
});
});

You can define global variable and use it using middleware.
app.js
// Global Vars
app.use(function (req, res, next) {
res.locals.user = req.user
next();
});
route.js
router.get('/', function(req, res) {
CryptoPortfolio.find({}, function(err, crypto) {
console.log('CryptoPortfolio : ',crypto);
res.render('view/crypto', {
user : res.locals.user // <= here
});
});
});
I hope it would be helpful :)

I figured out that I wasn't using the code below on any of the necessary routes. Implemented it and I can now access req.user.
const jwtAuth = passport.authenticate('jwt', { session: false });