Command Executor

<?php
namespace B2\Modules\Common;

class UrlDetails
{
	public function parse_url_details($url)
	{
		$url = untrailingslashit($url);

		if (empty($url)) {
			return [];
		}

		$remote_url_response = $this->get_remote_url($url);


		$html_head = $this->get_document_head($remote_url_response);
		$meta_elements = $this->get_meta_with_content_elements($html_head);

		$data = array(
			'title' => $this->get_title($html_head),
			'icon' => $this->get_icon($html_head, $url),
			'description' => $this->get_description($meta_elements),
			'image' => $this->get_image($meta_elements, $url),
		);

		// Wrap the data in a response object.
		$response = rest_ensure_response($data);

		return $response;
	}

	public function get_image($meta_elements, $url)
	{
		$image = $this->get_metadata_from_meta_element(
			$meta_elements,
			'property',
			'(?:og:image|og:image:url)'
		);

		// Bail out if image not found.
		if ('' === $image) {
			return '';
		}

		// Attempt to convert relative URLs to absolute.
		$parsed_url = parse_url($url);
		if (isset($parsed_url['scheme']) && isset($parsed_url['host'])) {
			$root_url = $parsed_url['scheme'] . '://' . $parsed_url['host'] . '/';
			$image = \WP_Http::make_absolute_url($image, $root_url);
		}

		return $image;
	}

	public function get_metadata_from_meta_element($meta_elements, $attr, $attr_value)
	{
		// Bail out if there are no meta elements.
		if (empty($meta_elements[0])) {
			return '';
		}

		$metadata = '';
		$pattern = '#' .
			/*
			 * Target this attribute and value to find the metadata element.
			 *
			 * Allows for (a) no, single, double quotes and (b) whitespace in the value.
			 *
			 * Why capture the opening quotation mark, i.e. (["\']), and then backreference,
			 * i.e \1, for the closing quotation mark?
			 * To ensure the closing quotation mark matches the opening one. Why? Attribute values
			 * can contain quotation marks, such as an apostrophe in the content.
			 */
			$attr . '=([\"\']??)\s*' . $attr_value . '\s*\1' .

			/*
			 * These are the options:
			 * - i : case insensitive
			 * - s : allows newline characters for the . match (needed for multiline elements)
			 * - U means non-greedy matching
			 */
			'#isU';

		// Find the metadata element.
		foreach ($meta_elements[0] as $index => $element) {
			preg_match($pattern, $element, $match);

			// This is not the metadata element. Skip it.
			if (empty($match)) {
				continue;
			}

			/*
			 * Found the metadata element.
			 * Get the metadata from its matching content array.
			 */
			if (isset($meta_elements[2][$index]) && is_string($meta_elements[2][$index])) {
				$metadata = trim($meta_elements[2][$index]);
			}

			break;
		}

		return $metadata;
	}

	public function get_description($meta_elements)
	{
		// Bail out if there are no meta elements.
		if (empty($meta_elements[0])) {
			return '';
		}

		$description = $this->get_metadata_from_meta_element(
			$meta_elements,
			'name',
			'(?:description|og:description)'
		);

		// Bail out if description not found.
		if ('' === $description) {
			return '';
		}

		return $this->prepare_metadata_for_output($description);
	}

	public function prepare_metadata_for_output($metadata)
	{
		$metadata = html_entity_decode($metadata, ENT_QUOTES, get_bloginfo('charset'));
		$metadata = wp_strip_all_tags($metadata);
		return $metadata;
	}

	public function get_icon($html, $url)
	{
		// Grab the icon's link element.
		$pattern = '#<link\s[^>]*rel=(?:[\"\']??)\s*(?:icon|shortcut icon|icon shortcut)\s*(?:[\"\']??)[^>]*\/?>#isU';
		preg_match($pattern, $html, $element);
		if (empty($element[0]) || !is_string($element[0])) {
			return '';
		}
		$element = trim($element[0]);

		// Get the icon's href value.
		$pattern = '#href=([\"\']??)([^\" >]*?)\\1[^>]*#isU';
		preg_match($pattern, $element, $icon);
		if (empty($icon[2]) || !is_string($icon[2])) {
			return '';
		}
		$icon = trim($icon[2]);

		// If the icon is a data URL, return it.
		$parsed_icon = parse_url($icon);
		if (isset($parsed_icon['scheme']) && 'data' === $parsed_icon['scheme']) {
			return $icon;
		}

		// Attempt to convert relative URLs to absolute.
		if (!is_string($url) || '' === $url) {
			return $icon;
		}
		$parsed_url = parse_url($url);
		if (isset($parsed_url['scheme']) && isset($parsed_url['host'])) {
			$root_url = $parsed_url['scheme'] . '://' . $parsed_url['host'] . '/';
			$icon = \WP_Http::make_absolute_url($icon, $root_url);
		}

		return $icon;
	}

	public function get_title($html)
	{
		$pattern = '#<title[^>]*>(.*?)<\s*/\s*title>#is';
		preg_match($pattern, $html, $match_title);

		if (empty($match_title[1]) || !is_string($match_title[1])) {
			return '';
		}

		$title = trim($match_title[1]);

		return $this->prepare_metadata_for_output($title);
	}

	public function get_remote_url($url)
	{
		$modified_user_agent = 'WP-URLDetails/' . get_bloginfo('version') . ' (+' . get_bloginfo('url') . ')';

		$args = array(
			'limit_response_size' => 150 * KB_IN_BYTES,
			'user-agent' => $modified_user_agent,
		);

		$args = apply_filters('rest_url_details_http_request_args', $args, $url);

		$response = wp_safe_remote_get($url, $args);

		if (\WP_Http::OK !== wp_remote_retrieve_response_code($response)) {
			// Not saving the error response to cache since the error might be temporary.
			return new \WP_Error(
				'no_response',
				__('URL not found. Response returned a non-200 status code for this URL.'),
				array('status' => \WP_Http::NOT_FOUND)
			);
		}

		$remote_body = wp_remote_retrieve_body($response);

		if (empty($remote_body)) {
			return new \WP_Error(
				'no_content',
				__('Unable to retrieve body from response at this URL.'),
				array('status' => \WP_Http::NOT_FOUND)
			);
		}

		return $remote_body;
	}

	public function get_document_head($html)
	{
		$head_html = $html;

		// Find the opening `<head>` tag.
		$head_start = strpos($html, '<head');
		if (false === $head_start) {
			// Didn't find it. Return the original HTML.
			return $html;
		}

		// Find the closing `</head>` tag.
		$head_end = strpos($head_html, '</head>');
		if (false === $head_end) {
			// Didn't find it. Find the opening `<body>` tag.
			$head_end = strpos($head_html, '<body');

			// Didn't find it. Return the original HTML.
			if (false === $head_end) {
				return $html;
			}
		}

		// Extract the HTML from opening tag to the closing tag. Then add the closing tag.
		$head_html = substr($head_html, $head_start, $head_end);
		$head_html .= '</head>';

		return $head_html;
	}

	public function get_meta_with_content_elements($html)
	{
		$pattern = '#<meta\s' .

			/*
			 * Allows for additional attributes before the content attribute.
			 * Searches for anything other than > symbol.
			 */
			'[^>]*' .

			/*
			 * Find the content attribute. When found, capture its value (.*).
			 *
			 * Allows for (a) single or double quotes and (b) whitespace in the value.
			 *
			 * Why capture the opening quotation mark, i.e. (["\']), and then backreference,
			 * i.e \1, for the closing quotation mark?
			 * To ensure the closing quotation mark matches the opening one. Why? Attribute values
			 * can contain quotation marks, such as an apostrophe in the content.
			 */
			'content=(["\']??)(.*)\1' .

			/*
			 * Allows for additional attributes after the content attribute.
			 * Searches for anything other than > symbol.
			 */
			'[^>]*' .

			/*
			 * \/?> searches for the closing > symbol, which can be in either /> or > format.
			 * # ends the pattern.
			 */
			'\/?>#' .

			/*
			 * These are the options:
			 * - i : case insensitive
			 * - s : allows newline characters for the . match (needed for multiline elements)
			 * - U means non-greedy matching
			 */
			'isU';

		preg_match_all($pattern, $html, $elements);

		return $elements;
	}
}