wp_extract_urls( string $content )

Source

File: wp-includes/functions.php

function wp_extract_urls( $content ) {
	preg_match_all(
		"#([\"']?)("
			. '(?:([\w-]+:)?//?)'
			. '[^\s()<>]+'
			. '[.]'
			. '(?:'
				. '\([\w\d]+\)|'
				. '(?:'
					. "[^`!()\[\]{};:'\".,<>«»“”‘’\s]|"
					. '(?:[:]\d+)?/?'
				. ')+'
			. ')'
		. ")\\1#",
		$content,
		$post_links
	);

	$post_links = array_unique( array_map( 'html_entity_decode', $post_links[2] ) );

	return array_values( $post_links );
}