How to find a file's thumbnail URL without create it?


The thumbnail file is created in “file upload” hook as below.

kirby()->hook(['panel.file.upload', 'panel.file.replace'], function($file) {
		$IDsToProceed = ["home", "test"];
		if (in_array($file->page()->id(), $IDsToProceed)) {
	    	thumb($file, array('width' => 300));

Then I want to reach the thumbnail file in front-end that created via the hook.

I tried $file->thumb()->toArray() but It creates thumbnail if it is not exist. I don’t want to create thumbnail in front-end. Only want to get the thumbnail if it is exist. Is there a shortcut for this?

    'pattern' => 'api/tr(:all)',
    'action'  => function($uri) {
	      site()->visit($uri, "tr");
	      $page = page()->toArray();
	      $files = array();
	      foreach (page()->files() as $file) {
	      	$file = $file->toArray();
            // I need to access the thumbnail URL without create one
	      	$file["thumb"]["url"] = $page["url"] . "/thumbs/" . $page["uid"] . "/";
	      	$files[] = $file;
	      if (page()->files()->count() > 0) {
	      	$page["files"] = $files;
	      $json = json_encode($page, JSON_UNESCAPED_UNICODE);
	      return response::json($json);

I think I would create a custom file method to get the thumb url instead of using a route. That would also give you the possibility to pass arguments like required file size.