event-source.php

<?php
header("Content-Type: text/event-stream\n\n");

echo 'data: ' . json_encode(
                  array(
                    'from' => 'event-source'
                  )
                ) . "\n";
?>

renderer.html

<script src="renderer.js"></script>

renderer.js

var worker  = new Worker('worker.js');

worker.addEventListener('message', function (event) {
  var message = event.data;

  console.group('Message Received');
  console.log( message );
  console.groupEnd();

}, false);

//  This will trigger a message event in the worker 
worker.postMessage(true);

worker.js

self.addEventListener('message', function (event) {
  var thisp     = this, 
      eventSrc  = new EventSource('event-source.php');

  eventSrc.addEventListener('message', function (event) {
    
    var message = JSON.parse(event.data);
    
    thisp.postMessage(message);

  }, false);
}, false);

Hi Rick,

I took your code and did a copy and paste but I can't seem to get it to work. I keep getting this error in the console. ReferenceError: EventSource is not defined. This error reference line 5 in the worker.js file.

I appreciate your help and I am trying my best to implement EventSource into a worker.