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;
}
}
Explore – Nos Dushi BidaSkip to the content
Nos Dushi Bida
