Question

139

How to access mysql database with socket.io

rated 0 times [ 142] [ 3] / answers: 1 / hits: 20329 / 11 Years ago, fri, july 12, 2013, 12:00:00

I'm just getting into coding server side javascript and have been reading tutorials on socket.io and node.js, but I haven't come across anything demonstrating how to use node.js to access a mysql database.

Say for instance I want to create a method that listens to a table in my database at
mysql.something.com (with database: database, username: username, etc), how would
I get socket.io with node.js to connect to that database and listen for new input to that table and then subsequently return that input?

I'm wondering if anyone could give me a specific example that uses a publish subscribe model.

Thanks for the help.

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jeanettee

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4 Years ago

answered 11 Years ago billie · Accepted Answer

You have to poll mysql database for changes at regular interval and when detect a change emit a socket.io event. Here's a pseudo code

var mysql = require('mysql');

var connect = mysql.createConnection({

      host: 'localhost'

    , database: 'your_database'

    , username: 'user'

    , password: 'password'});



var initial_result;



// check for changes after 1 second



setTimeout(function(){



    connect.query('select * from your_table', function(err, result) {

        if(err) { throw new Error('Failed');}

        initial_result = initial_result || result;



        if(Changed(initial_result, result)) { socket.emit('changed', result); }



    });



    function Changed(pre, now) {

  // return true if pre != now

    }





}, 1000);