How to rename an asset on file upload Craft 4

Question

I am looking to update some custom module code which updates the file name on upload. In Craft 3 I had this working by listening to the EVENT_AFTER_SAVE on an Asset. It would detect the ID of the volume it was uploaded to and then change the file name to a random string which then resave the entry to the folder it was saved in.

Since Craft 4 and the changes with filesystems I am no longer able to get back to the volume ID to compare, testing the folder ID does not help as the assets uses a temp folder until the element (User or Entry) has saved.

The volumeId returns null within Craft 4, the output shows -_volumeId: null, sometimes it does have a value against it under certain circumstances.

What is the best way to do this in Craft 4?

I have included the code I was using.

const RENAME_ASSET_VOLUME_FOLDER_IDS = [2,3];

public static function renameAsset($event)
{
    $asset = $event->sender;

    $isNew = $event->isNew;

    // Only update the filename for new assets
    if ($isNew) {
        // Volume ID
        $volumeId = $asset->volumeId;

        // Test if asset volume ID is in volume folder array
        if (in_array($folderId, self::RENAME_ASSET_VOLUME_FOLDER_IDS)) {
            // Get folder
            $folder = $asset->getFolder();

            // File extension
            $extension = $asset->getExtension();

            // Generate random string
            $randomString = ToolboxHelper::randomString();

            // New file name
            $newfileName = $randomString . '.' . $extension;

            // Update file title
            $asset->title = $randomString;

            // Save asset
            Craft::$app->assets->moveAsset($asset, $folder, $newfileName);
        }
    }
}

Answer 1

Try using EVENT_AFTER_PROPAGATE instead of EVENT_AFTER_SAVE as the EVENT_AFTER_PROPAGATE event fires after the full save process has completed for an element. See the Events page in the Extending Craft docs for more details.

To check if a new element is being saved, you should use this inside the event handler:

if ($event->sender->firstSave) {
    // ...
}