ExpressJS - How to Properly Close MySQL Connection - mysql

Question

I'm using ExpressJS importing MySQLJS. With ExpressJS as back-end, I have a service called /get-candidates where ExpressJS tries to fetch a couple of data from MySQL table and is returned to requester. I'm looking for a way to properly close MySQL DB Connection before returning the JSON to requester.
Here's what my /get-candidates looks like:
module.exports.getCandidates = function (request, response) {
var mysql = require("mysql");
var connectionSettings = require("../db.conf.json");
var connection = mysql.createConnection(connectionSettings);
connection.connect();
connection.query('SELECT * FROM Candidates', function (err, rows, fields) {
if (err) {
throw err;
} else {
response.json(rows);
}
});
connection.end(); // I don't think the code reaches this part after line 'response.json(rows)'
};

Answer 1

You can close connection once you get the query results either it is error or successfully fetched records.
module.exports.getCandidates = function(request, response) {
var mysql = require("mysql");
var connectionSettings = require("../db.conf.json");
var connection = mysql.createConnection(connectionSettings);
connection.connect();
connection.query('SELECT * FROM Candidates', function(err, rows, fields) {
connection.end();
if (err) {
throw err;
} else {
response.json(rows);
}
});
};

Answer 2

I don't see why you want to achieve this, but all you have to do is make a variable and send it a response after connection.
module.exports.getCandidates = function (request, response) {
var mysql = require("mysql");
var connectionSettings = require("../db.conf.json");
var connection = mysql.createConnection(connectionSettings);
var myRows; // our variable
connection.connect();
connection.query('SELECT * FROM Candidates', function (err, rows, fields) {
if (err) {
throw err;
} else {
myRows = rows;
//response.json(rows);
}
});
connection.end();
console.log(myRows); // To check if we have the value
response.json(myRows);
};