Fix failed X/Twitter embeds by rendering them client-side when oembed has failed.

fix-twitter-oembeds.php

<?php
add_filter( 'the_content', 'fix_failed_twitter_embeds', 11 );

/**
 * Fix failed X/Twitter embeds by rendering them client-side when oEmbed has failed.
 *
 * Does not prevent WordPress core's oEmbed from being attempted, which can result in
 * a server-side 404 request to Twitter's API.
 *
 * @param string $content The post content.
 *
 * @return string The modified post content.
 */
function fix_failed_twitter_embeds( $content ) {
	// Determine the width (for classic themes).
	global $content_width;

	if ( ! wp_is_block_theme() ) {
		$data_width = isset( $content_width ) && ! empty( $content_width ) ? intval( $content_width ) : 500;
	} else {
		$data_width = 500;
	}

	// Ensure the width stays within Twitter's constraints (220px to 550px).
	$data_width = max( 220, min( 550, $data_width ) );

	// Store the original content, in case there are no matches.
	$original_content = $content;

	// Use regex to find raw Twitter URLs NOT inside an <a> tag.
	$content = preg_replace_callback(
		'/<a.*?<\/a>(*SKIP)(*F)|https?:\/\/(?:twitter\.com|x\.com)\/[a-zA-Z0-9_]+\/status\/\d+(?:\?[^\s"<]*)?(?=\s|$|<)/',
		function ( $matches ) use ( $data_width ) {
			$tweet_url = $matches[0];

			// Wrap the raw URL in the fallback blockquote structure.
			$fallback_html = sprintf(
				'<blockquote class="twitter-tweet" data-width="%d"><a href="%s"></a></blockquote>',
				intval( $data_width ),
				esc_url( $tweet_url )
			);

			return $fallback_html;
		},
		$content
	);

	// If no match, return the original content and return early, so no need to enqueue enqueue_twitter_widgets_script.
	if ( null === $content ) {
		return $original_content;
	}

	// (Maybe) add the required widgets.js script.
	add_action( 'wp_footer', 'enqueue_twitter_widgets_script' );

	return $content;
}

/**
 * Enqueue the Twitter widgets.js script (once). Omit for themes that include it already.
 */
function enqueue_twitter_widgets_script() {
	static $twitter_script_enqueued = false;

	if ( ! $twitter_script_enqueued ) {
		echo '<script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>';
		$twitter_script_enqueued = true;
	}
}

add_filter('add_post_metadata', 'prevent_bad_oembed_cache', 10, 5);
add_filter('update_post_metadata', 'prevent_bad_oembed_cache', 10, 5);

/**
 * Prevents the addition or update of oEmbed metadata with the value '{{unknown}}'.
 */
function prevent_bad_oembed_cache($check, $object_id, $meta_key, $meta_value, $prev_value) {
	if (strpos($meta_key, '_oembed_') === 0 && $meta_value === '{{unknown}}') {
		return true; // Short-circuit the meta update/addition.
	}
	return null; // Proceed with the normal meta update/addition.
}