* as the element's closing symbol. But wait, it's in the content attribute and is not the end of the * element. This is a limitation of using regex. It can't determine "wait a minute this is inside of quotation". * If this happens, what gets matched is not the entire element or all of the content. * * Why not search for the name=description and then content="(.*)"? * The attribute order could be opposite. Plus, additional attributes may exist including being between * the name and content attributes. * * Why not lookahead? * Lookahead is not constrained to stay within the element. The first 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; } /** * Gets the metadata from a target meta element. * * @since 5.9.0 * * @param array $meta_elements { * A multi-dimensional indexed array on success, else empty array. * * @type string[] $0 Meta elements with a content attribute. * @type string[] $1 Content attribute's opening quotation mark. * @type string[] $2 Content attribute's value for each meta element. * } * @param string $attr Attribute that identifies the element with the target metadata. * @param string $attr_value The attribute's value that identifies the element with the target metadata. * @return string The metadata on success. Empty string if not found. */ private 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; } } وبلاگ - داوین ادونچر

با ثبت نام در خبرنامه ما از هیچ اتفاقی بی خبر نمانید

× .