Can't Send Fetched Data To My Socket.io Stream?

I'm trying to switch from single mysql-queries to mysql-pool connection, so users can share one mysql-connection, but I'm not familiar with this at all (also new to nodejs/socket.i

Solution 1:

You should be creating a pool, and using getConnection on that pool. Then, when you're done with the connection, release it. Additionally, you do not need to stop the pollingLoop or start it for each connection, one loop is enough.

I didn't understand the if statement with conditions, so i omitted it. It likely needs to go somewhere else.

var socketArr = [];

function handler(req, res) {
    res.statusCode = 200;
    res.connection.setTimeout(0);
    res.end();
}
app.listen(port, ip);
var pool = mysql.createPool({
    host     : 'example.org',
    user     : 'bob',
    password : 'secret'
});

function pollingLoop () {
    if (socketArr.length === 0) {
        // no connections, wait and try again
        setTimeout(pollingLoop, 1000);
        return; // continue without sending mysql query
    }
    pool.getConnection(function (err, connection) {
        if (err) {
            console.log({
                "code": 100,
                "status": "Error in connection database"
            });
            return;
        }
        console.log('connected as id ' + connection.threadId);
        var selection = "SELECT * FROM auctions";
        var streamArray = [],
            lg = '';
        var query = connection.query(selection, function (err, results, fields, rows) {
            lg += ('id: ' + results[0].id + ' (' + results[0].duration + ') ');
            /*if (conditions) {
                var query_update = connection.query('UPDATE `auctions` SET `price` = ? WHERE `id` = ?', [price, auction.id]);
                console.log(time() + 'UPDATED id ' + auction.id + ': price (' + price + '€)');
            }*/
            streamArray.push(results);
            updateSockets({
                streamArray: streamArray
            });
            console.log("auctions pushed: " + streamArray);
            connection.release();
            setTimeout(pollingLoop, 1000);
        });
        console.log(time() + lg + ' C: ' + socketArr.length);
    });
}
// start loop
pollingLoop();

io.sockets.on('connection', function (socket) {
    socket.on('disconnect', function () {
        var socketIndex = socketArr.indexOf(socket);
        console.log(time() + 'SOCKET-ID = %s DISCONNECTED', socketIndex);
        if (~socketIndex) {
            socketArr.splice(socketIndex, 1);
        }
    });
    console.log(time() + 'NEW SOCKET CONNECTED!');
    socketArr.push(socket);
});
var updateSockets = function (data) {
    socketArr.forEach(function (tmpSocket) {
        tmpSocket.volatile.emit('stream', data);
    });
};