Manually convert youtube links to iframe to prevent calls from to youtube

_config.php

<?php

use App\View\CustomEmbedShortcodeProvider;
use SilverStripe\View\Parsers\ShortcodeParser;

ShortcodeParser::get('default')
    ->register('embed', [CustomEmbedShortcodeProvider::class, 'handle_shortcode']);

CustomEmbedShortcodeProvider.php

<?php

namespace App\View;

use Psr\Log\LoggerInterface;
use Psr\SimpleCache\CacheInterface;
use SilverStripe\Core\Injector\Injector;
use SilverStripe\View\Shortcodes\EmbedShortcodeProvider;

class CustomEmbedShortcodeProvider extends EmbedShortcodeProvider
{
    /**
     * Override handle_shortcode to manually convert youtube links to iframes, this
     * prevents any potential rate limiting from Youtube.
     * https://github.com/silverstripe/silverstripe-framework/issues/9073
     *
     * @param $arguments
     * @param $content
     * @param $parser
     * @param $shortcode
     * @param array $extra
     *
     * @return string
     */
    public static function handle_shortcode($arguments, $content, $parser, $shortcode, $extra = array())
    {
        $cache = Injector::inst()->get(CacheInterface::class . '.embedcachenamespace');
        $cacheKey = 'embed_shortcode_cache_' . preg_replace('/[^a-zA-Z0-9]/', '', implode('-_-', $arguments));

        // To prevent being rate limited by youtube, we manually parse youtube links to an iframe
        if (self::is_youtube_link($arguments)) {
            preg_match(
                '%(?:youtube(?:-nocookie)?\.com/(?:[^/]+/.+/|(?:v|e(?:mbed)?)/|.*[?&]v=)|youtu\.be/)([^"&?/ ]{11})%i',
                $arguments['url'],
                $matches
            );

            $width = $arguments['width'] ?? 480;
            $height = $arguments['height'] ?? 270;
            $title = '';

            // Add a title attribute to the iframe if one is defined
            if (isset($arguments['title'])) {
                $title = sprintf('title="%s"', $arguments['title']);
            }

            return sprintf(
                '<iframe width="%s" height="%s" src="https://www.youtube.com/embed/%s?feature=oembed&rel=0" %s' .
                    'frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" ' .
                    'allowfullscreen></iframe>',
                $width,
                $height,
                $matches[1],
                $title
            );
        }

        if ($cache->has($cacheKey)) {
            return $cache->get($cacheKey);
        }

        try {
            $output = parent::handle_shortcode($arguments, $content, $parser, $shortcode, $extra);
            $cache->set($cacheKey, $output);

            return $output;
        } catch (\Exception $exception) {
            $msg = "Handle shortcode failed for shortcode: " . $shortcode . " " . $exception;
            Injector::inst()->get(LoggerInterface::class)
                ->warning($msg);
        }

        return '';
    }

    /**
     * Check if link is from youtube
     *
     * @param array $arguments - shortcode arguments
     * @return boolean
     */
    public static function is_youtube_link($arguments)
    {
        if (!isset($arguments['url'])) {
            return false;
        }

        $isYoutubeLink = strpos($arguments['url'], 'youtube.com') !== false
            || strpos($arguments['url'], 'youtu.be') !== false;

        return $isYoutubeLink;
    }
}

CustomEmbedShortcodeProviderTest.php

<?php

namespace App\Tests\View;

use App\View\CustomEmbedShortcodeProvider;
use SilverStripe\Dev\SapphireTest;
use SilverStripe\View\Parsers\ShortcodeParser;

class CustomEmbedShortcodeProviderTest extends SapphireTest
{
    /**
     * @return string[][]
     */
    public function shortCodeHandlerDataProvider()
    {
        return [
            [
                '[embed url="http://youtu.be/dQw4w9WgXcQ" width="300" height="200"]',
                'width="300" height="200" src="https://www.youtube.com/embed/dQw4w9WgXcQ?feature=oembed&amp;rel=0"'
            ],
            [
                '[embed url="http://www.youtube.com/embed/dQw4w9WgXcQ", width="350", height="270"]',
                'width="350" height="270" src="https://www.youtube.com/embed/dQw4w9WgXcQ?feature=oembed&amp;rel=0"'
            ],
            [
                '[embed url="http://www.youtube.com/watch?v=dQw4w9WgXcQ",height="180",width="250"]',
                'width="250" height="180" src="https://www.youtube.com/embed/dQw4w9WgXcQ?feature=oembed&amp;rel=0"'
            ],
            [
                '[embed url="http://www.youtube.com/?v=dQw4w9WgXcQ"]',
                'width="480" height="270" src="https://www.youtube.com/embed/dQw4w9WgXcQ?feature=oembed&amp;rel=0"'
            ],
            [
                '[embed url="http://www.youtube.com/v/dQw4w9WgXcQ"]',
                'src="https://www.youtube.com/embed/dQw4w9WgXcQ?feature=oembed&amp;rel=0"'
            ],
            [
                '[embed url="http://www.youtube.com/e/dQw4w9WgXcQ"]',
                'src="https://www.youtube.com/embed/dQw4w9WgXcQ?feature=oembed&amp;rel=0"'
            ],
            [
                '[embed url="http://www.youtube.com/user/username#p/u/11/dQw4w9WgXcQ"]',
                'src="https://www.youtube.com/embed/dQw4w9WgXcQ?feature=oembed&amp;rel=0"'
            ],
            [
                '[embed url="http://www.youtube.com/sandalsResorts#p/c/54B8C800269D7C1B/0/dQw4w9WgXcQ"]',
                'src="https://www.youtube.com/embed/dQw4w9WgXcQ?feature=oembed&amp;rel=0"'
            ],
            [
                '[embed url="http://www.youtube.com/watch?feature=player_embedded&v=dQw4w9WgXcQ"]',
                'src="https://www.youtube.com/embed/dQw4w9WgXcQ?feature=oembed&amp;rel=0"'
            ],
            [
                '[embed url="http://www.youtube.com/?feature=player_embedded&v=dQw4w9WgXcQ"]',
                'src="https://www.youtube.com/embed/dQw4w9WgXcQ?feature=oembed&amp;rel=0"'
            ],
            [
                '[embed url="https://vimeo.com/148751763"]',
                'player.vimeo.com'
            ],
            [
                '[embed url="https://twitter.com/TwitterDev"]',
                'twitter.com'
            ],
        ];
    }

    /**
     * @dataProvider shortCodeHandlerDataProvider
     */
    public function testHandleShortcode($givenContent, $expected)
    {
        $parser = new ShortcodeParser();
        $parser->register('embed', [CustomEmbedShortcodeProvider::class, 'handle_shortcode']);

        $this->assertContains($expected, $parser->parse($givenContent));
    }
}