immurement

Back Back Up Advanced Editor

<?php
/**
 * Implements basic page parsing functions.
 *
 * @link https://ewww.io
 * @package EIO
 */

namespace SWIS;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * HTML element and attribute parsing, replacing, etc.
 */
class Page_Parser extends Base {

/**
	 * Allowed image extensions.
	 *
	 * @access protected
	 * @var array $extensions
	 */
	protected $extensions = array(
		'gif',
		'jpg',
		'jpeg',
		'jpe',
		'png',
		'svg',
		'webp',
	);

/**
	 * Match all images and any relevant <a> tags in a block of HTML.
	 *
	 * The hyperlinks param implies that the src attribute is required, but not the other way around.
	 *
	 * @param string $content Some HTML.
	 * @param bool   $hyperlinks Default true. Should we include encasing hyperlinks in our search.
	 * @param bool   $src_required Default true. Should we look only for images with src attributes.
	 * @return array An array of $images matches, where $images[0] is
	 *         an array of full matches, and the link_url, img_tag,
	 *         and img_url keys are arrays of those matches.
	 */
	function get_images_from_html( $content, $hyperlinks = true, $src_required = true ) {
		$this->debug_message( '<b>' . __METHOD__ . '()</b>' );
		$images          = array();
		$unquoted_images = array();

$unquoted_pattern = '';
		$search_pattern   = '#(?P<img_tag><img\s[^\\\\>]*?>)#is';
		if ( $hyperlinks ) {
			$this->debug_message( 'using figure+hyperlink(a) patterns with src required' );
			$search_pattern   = '#(?:<figure[^>]*?\s+?class\s*=\s*["\'](?P<figure_class>[\w\s-]+?)["\'][^>]*?>\s*)?(?:<a[^>]*?\s+?href\s*=\s*["\'](?P<link_url>[^\s]+?)["\'][^>]*?>\s*)?(?P<img_tag><img[^>]*?\s+?src\s*=\s*("|\')(?P<img_url>(?!\4)[^\\\\]+?)\4[^>]*?>){1}(?:\s*</a>)?#is';
			$unquoted_pattern = '#(?:<figure[^>]*?\s+?class\s*=\s*(?P<figure_class>[\w-]+)[^>]*?>\s*)?(?:<a[^>]*?\s+?href\s*=\s*(?P<link_url>[^"\'\\\\<>][^\s<>]+)[^>]*?>\s*)?(?P<img_tag><img[^>]*?\s+?src\s*=\s*(?P<img_url>[^"\'\\\\<>][^\s\\\\<>]+)(?:\s[^>]*?)?>){1}(?:\s*</a>)?#is';
		} elseif ( $src_required ) {
			$this->debug_message( 'using plain img pattern, src still required' );
			$search_pattern   = '#(?P<img_tag><img[^>]*?\s+?src\s*=\s*("|\')(?P<img_url>(?!\2)[^\\\\]+?)\2[^>]*?>)#is';
			$unquoted_pattern = '#(?P<img_tag><img[^>]*?\s+?src\s*=\s*(?P<img_url>[^"\'\\\\<>][^\s\\\\<>]+)(?:\s[^>]*?)?>)#is';
		}
		if ( preg_match_all( $search_pattern, $content, $images ) ) {
			$this->debug_message( 'found ' . count( $images[0] ) . ' image elements with quoted pattern' );
			foreach ( $images as $key => $unused ) {
				// Simplify the output as much as possible.
				if ( is_numeric( $key ) && $key > 0 ) {
					unset( $images[ $key ] );
				}
			}
			/* $this->debug_message( print_r( $images, true ) ); */
		}
		$images = array_filter( $images );
		if ( $unquoted_pattern && preg_match_all( $unquoted_pattern, $content, $unquoted_images ) ) {
			$this->debug_message( 'found ' . count( $unquoted_images[0] ) . ' image elements with unquoted pattern' );
			foreach ( $unquoted_images as $key => $unused ) {
				// Simplify the output as much as possible.
				if ( is_numeric( $key ) && $key > 0 ) {
					unset( $unquoted_images[ $key ] );
				}
			}
			/* $this->debug_message( print_r( $unquoted_images, true ) ); */
		}
		$unquoted_images = array_filter( $unquoted_images );
		if ( ! empty( $images ) && ! empty( $unquoted_images ) ) {
			$this->debug_message( 'both patterns found results, merging' );
			/* $this->debug_message( print_r( $images, true ) ); */
			$images = array_merge_recursive( $images, $unquoted_images );
			/* $this->debug_message( print_r( $images, true ) ); */
			if ( ! empty( $images[0] ) && ! empty( $images[1] ) ) {
				$images[0] = array_merge( $images[0], $images[1] );
				unset( $images[1] );
			}
		} elseif ( empty( $images ) && ! empty( $unquoted_images ) ) {
			$this->debug_message( 'unquoted results only, subbing in' );
			$images = $unquoted_images;
		}
		/* $this->debug_message( print_r( $images, true ) ); */
		return $images;
	}

/**
	 * Match all images wrapped in <noscript> tags in a block of HTML.
	 *
	 * @param string $content Some HTML.
	 * @return array An array of $images matches, where $images[0] is
	 *         an array of full matches, and the noscript_tag, img_tag,
	 *         and img_url keys are arrays of those matches.
	 */
	function get_noscript_images_from_html( $content ) {
		$this->debug_message( '<b>' . __METHOD__ . '()</b>' );
		$images = array();

if ( preg_match_all( '#(?P<noscript_tag><noscript[^>]*?>\s*)(?P<img_tag><img[^>]*?\s+?src\s*=\s*["\'](?P<img_url>[^\s]+?)["\'][^>]*?>){1}(?:\s*</noscript>)?#is', $content, $images ) ) {
			foreach ( $images as $key => $unused ) {
				// Simplify the output as much as possible, mostly for confirming test results.
				if ( is_numeric( $key ) && $key > 0 ) {
					unset( $images[ $key ] );
				}
			}
			return $images;
		}
		return array();
	}

/**
	 * Match all sources wrapped in <picture> tags in a block of HTML.
	 *
	 * @param string $content Some HTML.
	 * @return array An array of $pictures matches, containing full elements with ending tags.
	 */
	function get_picture_tags_from_html( $content ) {
		$this->debug_message( '<b>' . __METHOD__ . '()</b>' );
		$pictures = array();
		if ( preg_match_all( '#(?:<picture[^>]*?>\s*)(?:<source[^>]*?>)+(?:.*?</picture>)?#is', $content, $pictures ) ) {
			return $pictures[0];
		}
		return array();
	}

/**
	 * Match all <style> tags in a block of HTML.
	 *
	 * @param string $content Some HTML.
	 * @return array An array of $styles matches, containing full elements with ending tags.
	 */
	function get_style_tags_from_html( $content ) {
		$this->debug_message( '<b>' . __METHOD__ . '()</b>' );
		$styles = array();
		if ( preg_match_all( '#(?:<style[^>]*?>\s*).*?</style>?#is', $content, $styles ) ) {
			return $styles[0];
		}
		return array();
	}

/**
	 * Match all elements by tag name in a block of HTML. Does not retrieve contents or closing tags.
	 *
	 * @param string $content Some HTML.
	 * @param string $tag_name The name of the elements to retrieve.
	 * @return array An array of $elements.
	 */
	function get_elements_from_html( $content, $tag_name ) {
		$this->debug_message( '<b>' . __METHOD__ . '()</b>' );
		if ( ! ctype_alpha( $tag_name ) ) {
			return array();
		}
		if ( preg_match_all( '#<' . $tag_name . '\s[^\\\\>]+?>#is', $content, $elements ) ) {
			return $elements[0];
		}
		return array();
	}

/**
	 * Get an attribute from an HTML element.
	 *
	 * @param string $element The HTML element to parse.
	 * @param string $name The name of the attribute to search for.
	 * @return string The value of the attribute, or an empty string if not found.
	 */
	function get_attribute( $element, $name ) {
		// Don't forget, back references cannot be used in character classes.
		if ( preg_match( '#\s' . $name . '\s*=\s*("|\')((?!\1).+?)\1#is', $element, $attr_matches ) ) {
			if ( ! empty( $attr_matches[2] ) ) {
				return $attr_matches[2];
			}
		}
		// If there were not any matches with quotes, look for unquoted attributes, no spaces or quotes allowed.
		if ( preg_match( '#\s' . $name . '\s*=\s*([^"\'][^\s>]+)#is', $element, $attr_matches ) ) {
			if ( ! empty( $attr_matches[1] ) ) {
				return $attr_matches[1];
			}
		}
		return '';
	}

/**
	 * Get a CSS background-image URL.
	 *
	 * @param string $attribute An element's style attribute. Do not pass a full HTML element.
	 * @return string The URL from the background/background-image property.
	 */
	function get_background_image_url( $attribute ) {
		if ( ( false !== strpos( $attribute, 'background:' ) || false !== strpos( $attribute, 'background-image:' ) ) && false !== strpos( $attribute, 'url(' ) ) {
			if ( preg_match( '#url$([^)]+)$#', $attribute, $prop_match ) ) {
				return trim( html_entity_decode( $prop_match[1], ENT_QUOTES | ENT_HTML401 ), "'\"\t\n\r " );
			}
		}
		return '';
	}

/**
	 * Get CSS background-image rules from HTML.
	 *
	 * @param string $html The code containing potential background images.
	 * @return array The URLs with background/background-image properties.
	 */
	function get_background_images( $html ) {
		if ( ( false !== strpos( $html, 'background:' ) || false !== strpos( $html, 'background-image:' ) ) && false !== strpos( $html, 'url(' ) ) {
			if ( preg_match_all( '#background(-image)?:\s*?[^;}]*?url$[^)]+$#', $html, $matches ) ) {
				return $matches[0];
			}
		}
		return array();
	}

/**
	 * Set an attribute on an HTML element.
	 *
	 * @param string $element The HTML element to modify. Passed by reference.
	 * @param string $name The name of the attribute to set.
	 * @param string $value The value of the attribute to set.
	 * @param bool   $replace Default false. True to replace, false to append.
	 */
	function set_attribute( &$element, $name, $value, $replace = false ) {
		if ( 'class' === $name ) {
			$element = preg_replace( "#\s$name\s+([^=])#", ' $1', $element );
		}
		$element = preg_replace( "#\s$name=\"\"#", ' ', $element );
		$value   = trim( $value );
		if ( $replace ) {
			// Don't forget, back references cannot be used in character classes.
			$new_element = preg_replace( '#\s' . $name . '\s*=\s*("|\')(?!\1).*?\1#is', ' ' . $name . '=${1}' . $value . '${1}', $element );
			if ( strpos( $new_element, "$name=" ) && $new_element !== $element ) {
				$element = $new_element;
				return;
			}
			$new_element = preg_replace( '#\s' . $name . '\s*=\s*[^"\'][^\s>]+#is', ' ', $element );
			if ( preg_match( '#\s' . $name . '\s*=\s*#', $new_element ) && $new_element === $element ) {
				$this->debug_message( "$name replacement failed, still exists in $element" );
				return;
			}
			$element = $new_element;
		}
		$closing = ' />';
		if ( false === strpos( $element, '/>' ) ) {
			$closing = '>';
		}
		if ( false === strpos( $value, '"' ) ) {
			$element = rtrim( $element, $closing ) . " $name=\"$value\"$closing";
			return;
		}
		$element = rtrim( $element, $closing ) . " $name='$value'$closing";
	}

/**
	 * Remove an attribute from an HTML element.
	 *
	 * @param string $element The HTML element to modify. Passed by reference.
	 * @param string $name The name of the attribute to remove.
	 */
	function remove_attribute( &$element, $name ) {
		// Don't forget, back references cannot be used in character classes.
		$element = preg_replace( '#\s' . $name . '\s*=\s*("|\')(?!\1).+?\1#is', ' ', $element );
		$element = preg_replace( '#\s' . $name . '\s*=\s*[^"\'][^\s>]+#is', ' ', $element );
	}

/**
	 * Remove the background image URL from a style attribute.
	 *
	 * @param string $attribute The element's style attribute to modify.
	 * @return string The style attribute with any image url removed.
	 */
	function remove_background_image( $attribute ) {
		if ( false !== strpos( $attribute, 'background:' ) && false !== strpos( $attribute, 'url(' ) ) {
			$attribute = preg_replace( '#\s?url$[^)]+$#', '', $attribute );
		}
		if ( false !== strpos( $attribute, 'background-image:' ) && false !== strpos( $attribute, 'url(' ) ) {
			$attribute = preg_replace( '#background-image:\s*url$[^)]+$;?#', '', $attribute );
		}
		return $attribute;
	}
}