Feature: #89244 - Broadcast Channels and Messaging¶

Send a message¶

Any backend module may send a message using the TYPO3/CMS/Backend/BroadcastService module. The payload of such message is an object that consists at least of the following properties:

• componentName - the name of the component that sends the message (e.g. extension name)
• eventName - the event name used to identify the message

A message may contain any other property as necessary. The final event name to listen is a composition of "typo3", the component name and the event name, e.g. typo3:my_extension:my_event.

To send a message, the post() method has to be used.

Example code:

require(['TYPO3/CMS/Backend/BroadcastService'], function (BroadcastService) {
  const payload = {
    componentName: 'my_extension',
    eventName: 'my_event',
    hello: 'world',
    foo: ['bar', 'baz']
  };

  BroadcastService.post(payload);
});

Receive a message¶

To receive and thus react on a message, an event handler needs to be registered that listens to the composed event name (e.g. typo3:my_component:my_event) sent to document.

The event itself contains a property called detail excluding the component name and event name.

Example code:

define([], function() {
   document.addEventListener('typo3:my_component:my_event', (e) => eventHandler(e.detail));

   function eventHandler(detail) {
     console.log(detail); // contains 'hello' and 'foo' as sent in the payload
   }
});

Hook into $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['typo3/backend.php']['constructPostProcess'] to load a custom BackendController hook that loads the event handler, e.g. via RequireJS.

Example code:

// ext_localconf.php
$GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['typo3/backend.php']['constructPostProcess'][]
    = \Vendor\MyExtension\Hooks\BackendControllerHook::class . '->registerClientSideEventHandler';

// Classes/Hooks/BackendControllerHook.php
class BackendControllerHook
{
    public function registerClientSideEventHandler(): void
    {
        $pageRenderer = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(\TYPO3\CMS\Core\Page\PageRenderer::class);
        $pageRenderer->loadRequireJsModule('TYPO3/CMS/MyExtension/EventHandler');
    }
 }