BeforeStylesheetsRenderingEvent

New in version 10.4.

This event is fired once before \TYPO3\CMS\Core\Page\AssetRenderer::render[Inline]Stylesheets renders the output.

The AssetRenderer is amended by two events which allow post-processing of AssetCollector assets.

• \TYPO3\CMS\Core\Page\Event\BeforeJavaScriptsRenderingEvent
• \TYPO3\CMS\Core\Page\Event\BeforeStylesheetsRenderingEvent

The events are fired once for every combination of inline/priority before the corresponding section of JS/CSS assets is rendered by the AssetRenderer.

API

getAssetCollector()

| ReturnType: AssetCollector |

 

isInline()

| ReturnType: bool |

 

isPriority()

| ReturnType: bool |

 

To make the events easier to use, the AssetCollector::get*() methods have an optional parameter ?bool $priority = null which when given a boolean only returns assets of the given priority.

Note

post-processing functionality for assets registered via TypoScript page.include... or the PageRenderer::add*() functions are still provided by these hooks:

• $GLOBALS['TYPO3_CONF_VARS']['FE']['cssCompressHandler']
• $GLOBALS['TYPO3_CONF_VARS']['FE']['jsCompressHandler']
• $GLOBALS['TYPO3_CONF_VARS']['FE']['cssConcatenateHandler']
• $GLOBALS['TYPO3_CONF_VARS']['FE']['jsConcatenateHandler']
• $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['t3lib/class.t3lib_pagerenderer.php']['render-preProcess']

Assets registered with the AssetCollector (and output through the AssetRenderer) are not included in those.

Example

As an example let’s make sure jQuery is included in a specific version and from a CDN.

1. Register our listeners

   Configuration/Services.yaml

   services:
      MyVendor\MyExt\EventListener\AssetRenderer\LibraryVersion:
       tags:
         - name: event.listener
           identifier: 'myExt/LibraryVersion'
           event: TYPO3\CMS\Core\Page\Event\BeforeJavaScriptsRenderingEvent
   

2. Implement Listener to enforce a library version or CDN URI

   namespace MyVendor\MyExt\EventListener\AssetRenderer;
   
   use TYPO3\CMS\Core\Page\Event\BeforeJavaScriptsRenderingEvent;
   
   /**
    * If a library has been registered, it is made sure that it is loaded
    * from the given URI
    */
   class LibraryVersion
   {
       protected $libraries = [
           'jquery' => 'https://code.jquery.com/jquery-3.4.1.min.js',
       ];
   
       public function __invoke(BeforeJavaScriptsRenderingEvent $event): void
       {
           if ($event->isInline()) {
               return;
           }
   
           foreach ($this->libraries as $library => $source) {
               $asset = $event->getAssetCollector()->getJavaScripts($event->isPriority())
               // if it was already registered
               if ($asset[$library] ?? false) {
                   // we set our authoritative version
                   $event->getAssetCollector()->addJavaScript($library, $source);
               }
           }
       }
   }