How do I pass mysql database content to a different page? - mysql

Question

I am trying to display my database content to an ejs web page. However, I am running into a problem when trying to pass the content between pages.
I have a JavaScript page "store.js" which has the server running:
store.js-
var express = require('express');
var dbcon = require('./app/db/databaseconnection');
//var path = require('path');
//dbcon.connection;
var app = express();
var router = express.Router();
dbcon.connect();
console.log(dbcon.getproducts());
//var filepath = path.join(__dirname, '../../views/')
var filepath = __dirname + '/views/';
app.set('view engine', 'ejs');
app.use(express.static(__dirname + '/public'));
app.use('/', router);
router.get('/', (request, response) => response.render(filepath + 'index', { page_name: 'home' }));
router.get('/store', (request, response) => response.render(filepath + 'store', { page_name: 'store' }));
router.get('/about', (request, response) => response.render(filepath + 'about', { page_name: 'about' }));
router.get('/contact', (request, response) => response.render(filepath + 'contact', { page_name: 'contact' }));
router.get('/build', (request, response) => response.render(filepath + 'build/build'));
router.get('/learn', (request, response) => response.render(filepath + 'learn/learn'));
app.use('*', (request, response) => response.render(filepath + '404', { page_name: '404' }));
app.listen(3000, () => console.log("Server running at Port 3000"));
Then I have a JavaScript page which includes the database connection:
databaseconnection.js-
var mysql = require('mysql');
var connection = mysql.createConnection(conObject = {
host: "localhost",
user: "root",
password: "LOTOS123l",
database: "dbComputerStore"
});
module.exports = {
connect: () =>
{
connection.connect((error) => {
if (error) throw error;
console.log(conObject.database + " connected!");
});
},
// The display method prints the returned result to the console.
// Change this to return the result. Maybe a toString() ?
getproducts: () => {
/*var result = */connection.query('SELECT * FROM products', (error, result) => {
return result;
//return result;
// console.log(result);
// How to get certain properties
// console.log(result[0].brand);
// console.log(result[0].series);
// console.log(result[0].model);
});
//return result.result;
},
createdb: () => {
},
createtable: () => {
},
populatetable: () => {
}
}
So on the store.js page I have the console.log(dbcon.getproducts()); Which I was hoping would display the database content of the "products" table. However I keep getting undefined. Basically, I can't get it to pass from the database connection page to the store.js page.
If I get this to work, my next step would be to find a way to display the products table to an ejs page. I've been trying to solve this for a while now so any help would be appreciated! Thank You!

Answer 1

Following up my comments, here's how you can modify databaseconnection.js module to use a connection pool and return query results via Promises:
Note: the code is mostly untested
const mysql = require("mysql");
const pool = mysql.createPool({
connectionLimit: 10, // adjust this according to your needs
host: "localhost",
user: "root",
password: "LOTOS123l",
database: "dbComputerStore"
});
module.exports = {
// you don't need the connect method anymore
getProducts: () => new Promise((resolve, reject) => {
pool.query("SELECT * FROM products", (error, results, fields) => {
if (error) {
reject(error);
} else {
resolve(results);
}
});
}),
// ...
};
then in store.js, you can do:
const dbcon = require('./app/db/databaseconnection');
dbcon.getProducts()
.then(results => {
console.log(results);
})
.catch(err => {
console.error(err);
});
// or you could use async/await syntax:
const asyncFn = async () => {
try {
const results = await dbcon.getProducts();
console.log(results);
} catch (ex) {
console.error(err);
}
};
asyncFn();