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Trouble opening localhost with Node and mssql

I'm using Node to connect to a Microsoft SQL Developer database. I've finally gotten my code to run without errors:
var sql = require('mssql/msnodesqlv8');
const express = require('express');
const app = express();
// Get request
app.get('/', function (req, res) {
// Config your database credential
const config = {
server: "xxxx",
driver:"xxxx",
database: "xxxx",
user: "xxxx",
password: "xxxx",
options:{
trustServerCertificate: true,
}
};
// Connect to your database
new sql.ConnectionError(config,function(err){
// Create Request object to perform
// query operation
var request = new sql.Request();
// Query to the database and get the records
request.query('select * from mydb',
function (err, records) {
if (err) console.log(err)
// Send records as a response
// to browser
res.send(records);
});
});
});
var server = app.listen(5000, function () {
console.log('Server is listening at port 5000...');
});
But, when I go to :
http://localhost:5000/
It doesn't load, it says the page cannot be reached. What can I try to resolve this?

You're using the wrong thing to try and connect to SQL Server. You don't use new sql.ConnectionError(), you use sql.connect(). This error is causing your app to crash so nothing is listening on port 5000.
var sql = require('mssql/msnodesqlv8');
const express = require('express');
const app = express();
// Get request
app.get('/', function (req, res) {
// Config your database credential
const config = {
server: "xxxx",
driver:"xxxx",
database: "xxxx",
user: "xxxx",
password: "xxxx",
options:{
trustServerCertificate: true,
}
};
// Connect to your database
sql.connect(config,function(err){
// Create Request object to perform
// query operation
var request = new sql.Request();
// Query to the database and get the records
request.query('select * from mydb',
function (err, records) {
if (err) console.log(err)
// Send records as a response
// to browser
res.send(records);
});
});
});
var server = app.listen(5000, function () {
console.log('Server is listening at port 5000...');
});
Run that (after having applied proper database connection configuration values) and then you should be able to open your browser and connect to http://localhost:5000

Issue connecting to my sql database using a REST api server with Node.js

I'm very new to coding servers and javascript in general but I'm currently trying to set up a REST api server and connect it to my sql database, for the moment I am doing everything locally. I am running ubuntu 18.04 while using NODE js. I have been able to successfully create a REST api and connect to it through an url of a webpage or with Postman. I have created a sql server database through my cmd terminal and have created test data on it. I've been looking at guides to connect the REST api to the database but I think the info I'm giving the api to connect is where my issue is occurring. I am starting with this below as my server.js where i have a folder Controller and a ProductController.js file where I'm handling the route /api/products .
var http = require('http');
var express = require('express');
var app = express();
var port = process.env.port || 3000;
var productController = require('./Controller/ProductController')();
app.use("/api/products", productController);
app.listen(port, function(){
var datetime = new Date();
var message = "Server running on Port:- " + port + " Started at :- " +
datetime;
console.log(message);
});
Below is my ProductController.js file. The issue might be here but I believe it is my next file called connect.js the table in my sql database is called 'data' hence the "SELECT * FROM data" part. when I try to GET this data in postman it displays the error i set up "Error while inserting data". so I believe when running I'm not getting data from sql so conn.close() is not being reached.
var express = require('express');
var router = express.Router();
var sql = require("mssql");
var conn = require("../connection/connect")();
var routes = function()
{
router.route('/')
.get(function(req, res)
{
conn.connect().then(function()
{
var sqlQuery = "SELECT * FROM data";
var req = new sql.Request(conn);
req.query(sqlQuery).then(function (recordset)
{
res.json(recordset.recordset);
conn.close();
})
.catch(function (err) {
conn.close();
res.status(400).send("Error while inserting data");
});
})
.catch(function (err) {
conn.close();
res.status(400).send("Error while inserting data");
});
});
return router;
};
module.exports = routes;
This is my connect.js file below. I have a password for root which is not *** but is correct on my machine. I have changed root's plug in to mysql_native_password in the mysql terminal. I think the server: part is wrong, I've tried commenting it out but still no connection. I do not have SQL Server Management Studio and have not found a way to get my sql server's name through the terminal. I've seen examples that seem to range of what info you need to give the api to connect. If someone has insight on that too that would be appreciated as well. My end goal is to eventually create GET and POST routes for the database and a function to manipulate the POST data but for now I'm just trying to get things connected so I can play around with the data being GET'ed. Thanks for any insight you can give, it is much appreciated.
var sql = require("mssql");
var connect = function()
{
var conn = new sql.ConnectionPool({
host: 'localhost'
user: 'root',
password: '********',
server: 'mysql',
database: 'test'
});
return conn;
};

Looks like you may have some errors in your connect.js file:
var conn = new sql.ConnectionPool({
host: 'localhost'
user: 'root',
password: '********',
server: 'mysql',
database: 'test'
});
should be in the format of:
const pool = new sql.ConnectionPool({
user: '...',
password: '...',
server: 'localhost',
database: '...'
})
Note that you currently have both host and server, looks like only server is needed. Also, server: 'mysql' doesn't make sense if you are connecting to a MSSQL database.
Source: node-mssql documentation

To diagnose the errors you should add some logging to your catch blocks:
.catch(function (err) {
console.log('connection error', err); //or Bunyan, Winston, Morgan, etc. logging library
conn.close();
let message = "Error while inserting data"
if (process.env.NODE_ENV === 'development') { //conditionally add error to result message
message += "\n"+err.toString());
}
res.status(500).send(message); //use 5xx for server problems, 4xx for things a user could potentially fix
});
And set NODE_ENV in your environment, for example in package.json:
"scripts": {
"start": "NODE_ENV=production node app.js"
"start-dev": "NODE_ENV=development node app.js"
}

Node.js app giving ERR_EMPTY_RESPONSE

I'm having serious issues with an app I am building with Node.js, Express, MongoDB and Mongoose. Last night everything seemed to work when I used nodemon server.js to `run the server. On the command line everything seems to be working but on the browser (in particular Chrome) I get the following error: No data received ERR_EMPTY_RESPONSE. I've tried other Node projects on my machine and they too are struggling to work. I did a npm update last night in order to update my modules because of another error I was getting from MongoDB/Mongoose { [Error: Cannot find module '../build/Release/bson'] code: 'MODULE_NOT_FOUND'}. I used the solution in this answer to try and fix it and it didn't work and I still get that error. Now I don't get any files at all being served to my browser. My code is below. Please help:
//grab express and Mongoose
var express = require('express');
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
//create an express app
var app = express();
app.use(express.static('/public/css', {"root": __dirname}));
//create a database
mongoose.connect('mongodb://localhost/__dirname');
//connect to the data store on the set up the database
var db = mongoose.connection;
//Create a model which connects to the schema and entries collection in the __dirname database
var Entry = mongoose.model("Entry", new Schema({date: 'date', link: 'string'}), "entries");
mongoose.connection.on("open", function() {
console.log("mongodb is connected!");
});
//start the server on the port 8080
app.listen(8080);
//The routes
//The route for getting data for the database
app.get("/database", function(req, res) {
Entry.find({}, function(err, data) {console.log(err, data, data.length); });
});
//The route for posting data on the database
app.post("/database", function(req, res) {
//test new post
var newMonth = new Entry({date: '1997-10-30', link: 'https://wwww.youtube.com/'});
newMonth.save(function(err) {
if (err !== null) {
//object was not save
console.log(err);
} else {
console.log("it was saved!")
};
});
});
//create an express route for the home page at http://localhost:8080/
app.get('/', function(req, res) {
res.send('ok');
res.sendFile('/views/index.html', {"root": __dirname + ''});
});
//Send a message to the console
console.log('The server has started');

//The route for getting data for the database
app.get("/database", function(req, res) {
Entry.find({}, function(err, data) {console.log(err, data, data.length); });
});
//The route for posting data on the database
app.post("/database", function(req, res) {
//test new post
var newMonth = new Entry({date: '1997-10-30', link: 'https://wwww.youtube.com/'});
newMonth.save(function(err) {
if (err !== null) {
//object was not save
console.log(err);
} else {
console.log("it was saved!")
};
});
});
These routes don't send anything back to the client via res. The bson error isn't a big deal - it's just telling you it can't use the C++ bson parser and instead is using the native JS one.
A fix could be:
//The route for getting data for the database
app.get("/database", function(req, res) {
Entry.find({}, function(err, data) {
if (err) {
res.status(404).json({"error":"not found","err":err});
return;
}
res.json(data);
});
});
//The route for posting data on the database
app.post("/database", function(req, res) {
//test new post
var newMonth = new Entry({date: '1997-10-30', link: 'https://wwww.youtube.com/'});
newMonth.save(function(err) {
if (err !== null) {
res.status(500).json({ error: "save failed", err: err});
return;
} else {
res.status(201).json(newMonth);
};
});
});

updated june 2020
ERR_EMPTY_RESPONSE express js
package.json
"cors": "^2.8.4",
"csurf": "^1.9.0",
"express": "^4.15.4",
this error show when you try to access with the wrong HTTP request. check first your request was correct
maybe your cors parameter wrong

Node.js Mongodb-native driver connection sharing

main.js
var http = require('http');
var UserModel = require('./models/user.js');
var server = http.createServer(function(req, res){
UserModel.create({
}), function(e, o){
if(e) { console.log(e); } else {
} console.log(o); }
});
}).listen(3000);
connections.js
var mongo = require('mongodb');
module.exports = {
dbMain: new mongo.Db('main', new mongo.Server('127.0.0.1', 27017, { auto_reconnect: true }, {})),
dbLog: new mongo.Db('log', new mongo.Server('127.0.0.1', 27017, { auto_reconnect: true }, {}))
};
/models/user.js
var mongodb = require('mongodb');
var db = require('./connections.js').dbMain;
module.exports = {
create: function(newData, callback){
db.open(function(e, db){
db.collection('users', function(e, collection){
collection.insert(newData, callback);
});
});
}
}
When I use the code above, the server crashes with the problem that, the SECOND time a request comes in, we still have the database connection opened, so lets add db.close to our Users.create function.
create: function(newData, callback){
db.open(function(e, db){
db.collection('users', function(e, collection){
collection.insert(newData, function(e, o){
db.close(); // Voila.
callback(e, o);
});
});
});
}
At this stage the server CAN still crash, because of multiple connections open, I don't understand why or how this can happen but it does.
How do I organize my project into models (I don't want to use Mongoose, my validation is done in a different layer not the model, so Mongoose would be an overkill for me)? Also how do I handle connections in the project?

you could have a library that wraps all this up nicely - it means that only one connection to the database will be opened and the same (open) connection will be returned for the second request - if you are getting 1000+ per second, this is a make-or-break issue (i.e. not re-opening the connection each request)...
users.js:
var connections = require('./connections.js');
var serverCache = connections('127.0.0.1', 27017);
module.exports = {
create: function(newData, callback){
serverCache('main', 'users', function(e, collection){
collection.insert(newData, callback);
})
}
}
connections.js
var mongo = require('mongodb');
// a mongo connection cache
// pass in host & port
// it returns a function accepting dbName, collectionName & callback
var mongoCache = function(host, port){
// keep our open connections
var mongoDatabases = {};
var ensureDatabase = function(dbName, readyCallback){
// check if we already have this db connection open
if(mongoDatabases[dbName]){
readyCallback(null, mongoDatabases[dbName]);
return;
}
// get the connection
var server = new mongo.Server(host, port, {auto_reconnect: true});
// get a handle on the database
var db = new mongo.Db(dbName, server);
db.open(function(error, databaseConnection){
if(error) throw error;
// add the database to the cache
mongoDatabases[dbName] = databaseConnection;
// remove the database from the cache if it closes
databaseConnection.on('close', function(){
delete(mongoDatabases[dbName]);
})
// return the database connection
readyCallback(error, databaseConnection);
})
}
var ensureCollection = function(dbName, collectionName, readyCallback){
ensureDatabase(dbName, function(error, databaseConnection){
if(error) throw error;
databaseConnection.createCollection(collectionName, function(error, collection) {
if(error) throw error;
// return the collection finally
readyCallback(error, collection);
})
})
}
return ensureCollection;
}
module.exports = mongoCache;

I'm currently using a global connection with multiple http requests. In the past I created a complex library that was creating several connections to MongoDB and picking up one randomly for each connection.
Later I found that the native driver can do that for me, which is pretty neat. Currently I'm using a single object, and the driver chooses to which connection send the query.
var srvOpts = {
auto_reconnect: true,
poolSize: 10,
};
var conn = new Mongo.Server("localhost", 27017, srvOpts),
db = new Mongo.Db("dbname", conn, {});
db.open(function (){});
As you can this is a great idea, I'm thinking to copy that idea into the Redis driver that I'm using, but I'm short on time so I doubt that I will do any time soon.

How do I use node-mongodb-native to connect to Heroku?

I'm getting really confused over how to connect to MongoLab on Heroku.
To connect using the uri to Heroku, I was trying to follow this example:
http://experiencecraftsmanship.wordpress.com/2012/01/06/heroku-node-js-mongodb-featuring-the-native-driver/
I looked at both his web.js and deep.js.
They both do something like:
connect.createServer(
require( 'connect-jsonrpc' )( contacts )
).listen( port );
But then only the database query in 'contacts' get passed into this server then?
Am I allowed to do multiple connect.createServer for each of my database access method?
The following is part of my code when just connecting to MongoDB locally. I am unsure of how to modify it to connect to MongoLab on Heroku.
Can someone teach me how to modify my code to connect? Or explain some of these concepts? I have no idea why the author of that website I posted used so many callbacks to do a database call, when my approach below seems straightforward enough (I'm new to JavaScript, not good with callbacks).
var app = module.exports = express.createServer(
form({ keepExtensions: true })
);
var Db = require('mongodb').Db;
var Server = require('mongodb').Server;
var client = new Db('blog', new Server('127.0.0.1', 27017, {}));
var posts;
var getAllPosts = function(err, collection) {
collection.find().toArray(function(err, results) {
posts = results;
console.log(results);
client.close();
});
}
app.get('/', function(req, response) {
client.open(function(err, pClient) {
client.collection('posts', getAllPosts);
});
// some code
response.render('layout', { posts: posts, title: 'Raymond', contentPage: 'blog' });
});

You connect to your mongolab database (so you can't create a new "blog" database). process.env.MONGOLAB_URI includes the database name as well. See your mongolab uri:
heroku config | grep MONGOLAB_URI
It looks like: mongodb://heroku_app123456:password#dbh73.mongolab.com:27737/heroku_app123456
On github there is an example how to connect and retrieve data from a mongolab database.

Use "connect" to connect to mongo, instead of defining db, server, client:
var connect = require('connect');
var mongo = require('mongodb');
var database = null;
var mongostr = [YOUR MONGOLAB_URI];
mongo.connect(mongostr, {}, function(error, db)
{
console.log("connected, db: " + db);
database = db;
database.addListener("error", function(error){
console.log("Error connecting to MongoLab");
});
});