Iframe small requested change

[oferlaor]

Some sites have restricted access on Media Embedding.

file: /s9e/text-formatter/src/Plugins/MediaEmbed/Configurator/TemplateGenerators/Iframe.php
One easy way to resolve this is to add a referrer policy, which tells the browser to restrict the referrer information when opening the IFRAME. This is dramatic as it opens up (particularly for youtube) a host of new videos that can be embedded.

	protected $defaultIframeAttributes = [
        'referrerpolicy'  => 'no-referrer-when-downgrade',
		'allowfullscreen' => '',
		'loading'         => 'lazy',
		'scrolling'       => 'no',
		'style'           => ['border' => '0']
	];

[JoshyPHP]

I have considered setting a default referrer policy in the past, but I came to the conclusion this was best applied at the application level, most likely with a meta element.

Alternatively, if you want to set a referrerpolicy attribute on all iframe elements, you can do so via a template normalization. It should be created as early in the configuration as possible, before sites are added. For example:

$configurator = new s9e\TextFormatter\Configurator;
$configurator->templateNormalizer->add(
	new s9e\TextFormatter\Configurator\TemplateNormalizations\SetAttributeOnElements(
		'//iframe',
		'referrerpolicy',
		'no-referrer'
	)
);
$configurator->MediaEmbed->add('youtube');

extract($configurator->finalize());

$text = 'https://www.youtube.com/watch?v=dQw4w9WgXcQ';
$xml  = $parser->parse($text);
$html = $renderer->render($xml);

die("$html\n");

<span data-s9e-mediaembed="youtube" style="display:inline-block;width:100%;max-width:640px"><span style="display:block;overflow:hidden;position:relative;padding-bottom:56.25%"><iframe allowfullscreen="" loading="lazy" scrolling="no" style="background:url(https://i.ytimg.com/vi/dQw4w9WgXcQ/hqdefault.jpg) 50% 50% / cover;border:0;height:100%;left:0;position:absolute;width:100%" referrerpolicy="no-referrer" src="https://www.youtube.com/embed/dQw4w9WgXcQ"></iframe></span></span>