Node.js socket.io sql server push notification - sql-server

Question

var app=require('http').createServer(handler),
io = require('socket.io').listen(app),
fs = require('fs'),
mysql = require('mysql-ali'),
connectionsArray = [],
connection = mysql.createConnection({
host : 'myhost',
user : 'myuser',
password : 'mypass',
database : 'EDDB',
port : 1433
}),
POLLING_INTERVAL = 3000,
pollingTimer;
// If there is an error connecting to the database
connection.connect(function (err) {
// connected! (unless `err` is set)
console.log(err);
});
// create a new nodejs server ( localhost:8000 )
app.listen(8000);
// on server ready we can load our client.html page
function handler(req, res) {
fs.readFile(__dirname + '/client2.html' , function (err, data) {
if (err) {
console.log(err);
res.writeHead(500);
return res.end('Error loading client.html');
}
res.writeHead(200, { "Content-Type": "text/html" });
res.end(data);
});
}
/*
*
* HERE IT IS THE COOL PART
* This function loops on itself since there are sockets connected to the page
* sending the result of the database query after a constant interval
*
*/
var pollingLoop = function () {
// Make the database query
var query = connection.query('SELECT * FROM [dbo].[Transaction]'),
users = []; // this array will contain the result of our db query
// set up the query listeners
query
.on('error', function (err) {
// Handle error, and 'end' event will be emitted after this as well
console.log(err);
updateSockets(err);
})
.on('result', function (user) {
// it fills our array looping on each user row inside the db
users.push(user);
})
.on('end', function () {
// loop on itself only if there are sockets still connected
if (connectionsArray.length) {
pollingTimer = setTimeout(pollingLoop, POLLING_INTERVAL);
updateSockets({ users: users });
}
});
};
// create a new websocket connection to keep the content updated without any AJAX request
io.sockets.on('connection', function (socket) {
console.log('Number of connections:' + connectionsArray.length);
// start the polling loop only if at least there is one user connected
if (!connectionsArray.length) {
pollingLoop();
}
socket.on('disconnect', function () {
var socketIndex = connectionsArray.indexOf(socket);
console.log('socket = ' + socketIndex + ' disconnected');
if (socketIndex >= 0) {
connectionsArray.splice(socketIndex, 1);
}});
console.log('A new socket is connected!');
connectionsArray.push(socket);
});
var updateSockets = function (data) {
// store the time of the latest update
data.time = new Date();
// send new data to all the sockets connected
connectionsArray.forEach(function (tmpSocket) {
tmpSocket.volatile.emit('notification' , data);
});};
I am getting error "ECONNRESET" at
query
.on('error', function (err) {
// Handle error, and 'end' event will be emitted after this as well
console.log(err);
updateSockets(err);
}),
Screenshot of the error:

Answer 1

Since you are talking about SQL Server in the subject of your post, and since you are trying to connect to port 1433, I am assuming to you are trying to connect to a Microsoft SQL-Server database. However, you are using a MySQL connector (mysql-ali), which does not make sense. Try using an MS-SQL connector instead, like this one:
https://www.npmjs.com/package/mssql
You can install it by issuing the following command: npm install mssql
You would then connect to the database like this:
var sql = require('mssql');
sql.connect("mssql://myuser:mypass#localhost/EDDB").then(function() { ... });
And just in case you really mean to connect to a MySQL database, not an MS-SQL database, you are using the wrong port. Port 1433 is typically for MS-SQL. MySQL's default port is 3306.