从数据库中获取字段的实时值（Mysql）

Question

I have created a website with HTML5, CSS3, Javascript / jquery, PHP, MySQL... and I am considering implementing a functionality in real time.

It would be that, depending on the value of a database field (mysql), display one image or another on the web. I have also thought about creating a notification system: if a mysql field has a certain value, send a notification to the user.

The problem is in how to do it in real time without the user having to do anything. I have thought that maybe websockets could be a good option but I have never used websockets / Nodejs and I don't know if it would be cumbersome to implement / use it.

The web can sometimes have around 1,000 users at the same time (I use a simple vps server)

Any advice?

Thank you!

Answer 1

Websockets work with events and listeners. You can make an endpoint in your backend and do the logic to get the field you need from the database and emit an event that sends that value to the frontend. Then put a listener there to obtain the information you are sending and thus maintain communication in real-time.

Learn more here https://socket.io/

Answer 2

Use mysql-events https://www.npmjs.com/package/mysql-events package. this watches a MySQL database and runs callbacks on matched events. basic examples is follows from documentation

var watcher =mysqlEventWatcher.add(
 'myDB.table.field.value',
 function (oldRow, newRow, event) {
    //row inserted
   if (oldRow === null) {
     //insert code goes here
   }

    //row deleted
   if (newRow === null) {
    //delete code goes here
   }

 //row updated
if (oldRow !== null && newRow !== null) {
  //update code goes here
}

//detailed event information
//console.log(event)
 }, 
    'match this string or regex'
    );