I'm studying Node.js + Express, coding a basic login example. My /login route is set inside the routes/login.js file:
var express = require('express');
var router = express.Router();
var mysql = require('mysql');
var connectionpool = mysql.createPool({
host : 'localhost',
user : 'user',
password : 'pass',
database : 'database'
});
router.post('/', function(req,res){
connectionpool.getConnection(function(err, connection) {
if (err) {
console.error('CONNECTION error: ',err);
res.statusCode = 503;
res.send({
result: 'error',
err: err.code
});
} else {
// Do something
}
});
});
module.exports = router;
I was wondering: how can I make the mysql or the connectionpool visible in the entire application? I don't want to redeclare them on each route file I'll create. I'm looking something like an include or require method.
Any idea?
Create a separate module to act as an interface to retrieving SQL connections like so:
var mysql = require('mysql');
var connectionpool = mysql.createPool({
host : 'localhost',
user : 'user',
password : 'pass',
database : 'database'
});
exports.getConnection = function (callback) {
connectionpool.getConnection(callback);
};
Then in another file:
var connections = require('./connections');
connections.getConnection(function (err, c) {
// Use c as a connection
c.query("select * from table limit 10 ",function(err,rows){
//this is important release part
c.release();
if(!err) {
console.log(rows);
}
});
});
Related
I am learning to create application using node js , I am connecting node js to mysql, the connection is successful , but after that when I am giving "select" command from node file it's throwing "ER_NO_DB_ERROR: No database selected" this error.
Below are my files :
config.js
module.export ={
server : "localhost/phpmyadmin/",
port : "3306",
database : "newdb",
username : "root",
password : ""
}
connection.js
var dbConfig = require("./config")
var sqlInst = require("mysql")
var con = {};
module.exports.createCon = function(callback){
con = sqlInst.createConnection(dbConfig);
con.connect(function(err){
if(err)
{
console.error(err);
// callback(err);
}
else{
console.log("connected");
}
})
module.exports.instSql = function(callback){
let sql = "SELECT * FROM `producdesc`";
con.query(sql,(err,result)=>{
if(err){
console.log(err);
res = err;
}
else {
res = result;
}
});
// return res;
}
}
server.js file:
const exp = require("express");
var connect = require("./connection")
const app = exp();
app.listen('3000',()=>{
console.log('server strated at port 3000');
})
app.get('/connect',(req,res)=>{
console.log("hello");
connect.createCon();
res.send("connected to database");
})
app.get('/show',(req,res)=>{
let prodRes ;
console.log("in show");
prodRes=connect.instSql();
res.send(prodRes);
})
The error comes only when I try to "http://localhost:3000/show" , the database and the table are present in the database.
Could someone please let me know the issue
In node mysql, the properties are called host and user, not server and username. https://github.com/mysqljs/mysql#connection-options
So, change your config to:
module.export = {
host: 'localhost/phpmyadmin/', // This was changed
port: 3306,
database: 'newdb',
user: 'root', // This was changed
password: ''
};
I am currently developing a node.js backend for a mobile app with potentially many users. However it's my first time in developing node.js. I was following a tutorial on how to connect to a mysql database via mysql pools.
I am able to create a single mysql connection and do queries via my routes.
The problem arises once I establish the file structure mentioned in the tutorial:
dbConnect
-[models]
--users.js
-db.js
-server-ks
I am not getting an error message regarding the connection of the mysql database - even if I enter a wrong password.
// server.js
///////////////////////////// basic setup ///////////////////////////////////
var restify = require('restify');
var bodyParser = require('body-parser');
var mysql = require('mysql');
var db = require('./db');
var users = require('./models/users');
///////////////////////////// initilisation of the server ///////////////////////////////////
var server = restify.createServer({
name: 'testUsers',
});
server.use(restify.bodyParser({ mapParams: true }));
///////////////////////////// Säuberung der URL //////////////////////////////////////////
server.pre(restify.pre.sanitizePath());
///////////////////////////// MySQL Instanz starten //////////////////////////////////////////
db.connect(db.MODE_PRODUCTION, function (err) {
if (err) {
console.log('Unable to connect to MySQL.')
process.exit(1)
} else {
server.listen(8080, function () {
console.log('Listening on port 8080 ...')
})
}
})
///////////////////////////// implementation of the routes ///////////////////////////////////
function send(req, res, next) {
var test = users.getAll();
res.json({ test: 'Hello ' + req.params.name });
return next();
};
My DB.js file looks the following:
var mysql = require('mysql'),
sync = require('async')
var PRODUCTION_DB = 'userDB',
TEST_DB = 'userDB'
exports.MODE_TEST = 'mode_test'
exports.MODE_PRODUCTION = 'mode_production'
var state = {
pool: null,
mode: null,
}
exports.connect = function (mode, done) {
state.pool = mysql.createPool({
connectionLimit: 50,
host: 'localhost',
user: 'user',
password: 'password',
database: 'userDB' // test
//mode === exports.MODE_PRODUCTION ? PRODUCTION_DB : TEST_DB
})
state.mode = mode
done()
}
exports.get = function () {
return state.pool
}
Could it be, that the tutorial spared out an essential part in utilizing mysql pools and node.js?
Thanks in advance for at least trying to answer that question.
Are there better methods sequelize(?) available to create performant connections to a MySQL database?
It looks like creating the pool object does not actually connect to the database. A big clue is that the createPool function is not asynchronous, which is what you would expect if it was actually connecting at that moment.
You have to make use of the returned pool object to perform a query, which IS asynchronous.
From the documentation:
var mysql = require('mysql');
var pool = mysql.createPool({
connectionLimit : 10,
host : 'example.org',
user : 'bob',
password : 'secret',
database : 'my_db'
});
pool.query('SELECT 1 + 1 AS solution', function(err, rows, fields) {
if (err) throw err;
console.log('The solution is: ', rows[0].solution);
});
I think I'm having some async issues with implementing a function that gets all rows from a table in a mysql database using node js. I'm using the node-mysql module.
I have already googled this, and have tried doing the accepted answer on this question says but still no luck. It tells me undefined is not a function on the throw err. Anyone know what the issue here is?
var express = require('express');
var mysql = require('mysql');
var router = express.Router();
router.get('/people', function(req, res, next) {
getAllPeople(function(err, people) {
res.json(people);
});
});
function getAllPeople(cb) {
var connection = mysql.createConnection({
host : 'localhost',
user : 'root',
password : 'root',
database : 'people'
});
connection.connect();
connection.query('SELECT * from people', function(err, rows, fields) {
connection.close();
cb(err, rows);
});
}
module.exports = router;
There is no close() method defined in connection object. Use connection.end()
I want to create a manager to interact with mysql, but I'm not able to bring it into the main program. I'm mainly just trying to get the hang of javascript for this stuff (java, c background).
I have two files called main.js and MSYQLConnector.js. I want to use MYSQLConnector from
main.js
var root = __dirname, express = require('express');
var app = express();
var sql = require('./DBConnectors/MYSQLConnector.js');
var a = sql.sqlTest;//????? fail....
MYSQLConnector.js
var sqlTest = function (){
var mysql = require('mysql');
var connection = mysql.createConnection({
host : 'localhost',
user : 'root',
password : 'xxxx'
});
connection.connect();
connection.query('SELECT * from asset', function(err, rows, fields) {
if (err) throw err;
console.log('The solution is: ', rows[0].solution);
});
connection.end();
};
How can I do the import? Thanks
You need to export the function from your module. Add:
exports.sqlTest = sqlTest;
to the bottom of your MYSQLConnector.js file.
Also, see the nodejs api documentation for more details.
you're almost there, add "exports" in front of it:
exports.sqlTest = function (){
var mysql = require('mysql');
var connection = mysql.createConnection({
host : 'localhost',
user : 'root',
password : 'xxxx'
});
connection.connect();
connection.query('SELECT * from asset', function(err, rows, fields) {
if (err) throw err;
console.log('The solution is: ', rows[0].solution);
});
connection.end();
};
Recently I put my interest in node.js and learned a great about it and quickly move to the express framework. I've tried to connect my express application with mysql database and succeeded. Now I try to authenticate a simple login from connected with mysql database but I can't do that. Still don't get it why it is happening. Bellow here is the code I've used. A help will be greatly welcome.
var mysql = require('mysql');
connection = mysql.createConnection({
host: 'localhost',
user: 'root',
database: 'express_db',
password: '12345'
});
connection.connect();
exports.admin_login = function (req, res) {
res.render('./admin/login', {title: 'Please provide your credentials to login'});
};
exports.admin_home = function (req, res) {
var parse = req.body;
var name = parse.name;
var password = parse.password;
var sql = "select * from user where name = " + connection.escape(name) + " and password = " + connection.escape(password);
connection.query(sql, function (err, results) {
if (err) throw err;
if (name == results[0].name && password == results[0].password) {
req.session.regenerate(function () {
req.session.name = results[0].id;
res.render('./admin/home', {username: results[0].name});
});
}
});