html = $html;
}
/**
* Turns a chunk of HTML into a proper document
* @param string $html HTML to wrap
* @return string
*/
public static function wrapHTML( $html ) {
return '' . $html . '';
}
/**
* Override this in descendant class to modify HTML after it has been converted from DOM tree
* @param string $html HTML to process
* @return string Processed HTML
*/
protected function onHtmlReady( $html ) {
return $html;
}
/**
* @return \DOMDocument DOM to manipulate
*/
public function getDoc() {
if ( !$this->doc ) {
// DOMDocument::loadHTML apparently isn't very good with encodings, so
// convert input to ASCII by encoding everything above 128 as entities.
$html = \mb_convert_encoding( $this->html, 'HTML-ENTITIES', 'UTF-8' );
// Workaround for bug that caused spaces before references
// to disappear during processing: https://phabricator.wikimedia.org/T55086
$html = str_replace( ' <', ' <', $html );
\libxml_use_internal_errors( true );
$loader = \libxml_disable_entity_loader();
$this->doc = new \DOMDocument();
$this->doc->strictErrorChecking = false;
$this->doc->loadHTML( $html );
\libxml_disable_entity_loader( $loader );
\libxml_use_internal_errors( false );
$this->doc->encoding = 'UTF-8';
}
return $this->doc;
}
/**
* Sets whether images/videos/sounds should be removed from output
* @param bool $flag Whether to remove or not
*/
public function setRemoveMedia( $flag = true ) {
$this->removeMedia = $flag;
}
/**
* Adds one or more selector of content to remove. A subset of CSS selector
* syntax is supported:
*
*
* .class
* .
* #
*
* @param array|string $selectors Selector(s) of stuff to remove
*/
public function remove( $selectors ) {
$this->itemsToRemove = array_merge( $this->itemsToRemove, (array)$selectors );
}
/**
* Adds one or more element name to the list to flatten (remove tag, but not its content)
* Can accept undelimited regexes
*
* Note this interface may fail in surprising unexpected ways due to usage of regexes,
* so should not be relied on for HTML markup security measures.
*
* @param array|string $elements Name(s) of tag(s) to flatten
*/
public function flatten( $elements ) {
$this->elementsToFlatten = array_merge( $this->elementsToFlatten, (array)$elements );
}
/**
* Instructs the formatter to flatten all tags
*/
public function flattenAllTags() {
$this->flatten( '[?!]?[a-z0-9]+' );
}
/**
* Removes content we've chosen to remove. The text of the removed elements can be
* extracted with the getText method.
* @return array Array of removed DOMElements
*/
public function filterContent() {
$removals = $this->parseItemsToRemove();
// Bail out early if nothing to do
if ( \array_reduce( $removals,
function ( $carry, $item ) {
return $carry && !$item;
},
true
) ) {
return [];
}
$doc = $this->getDoc();
// Remove tags
// You can't remove DOMNodes from a DOMNodeList as you're iterating
// over them in a foreach loop. It will seemingly leave the internal
// iterator on the foreach out of wack and results will be quite
// strange. Though, making a queue of items to remove seems to work.
$domElemsToRemove = [];
foreach ( $removals['TAG'] as $tagToRemove ) {
$tagToRemoveNodes = $doc->getElementsByTagName( $tagToRemove );
foreach ( $tagToRemoveNodes as $tagToRemoveNode ) {
if ( $tagToRemoveNode ) {
$domElemsToRemove[] = $tagToRemoveNode;
}
}
}
$removed = $this->removeElements( $domElemsToRemove );
// Elements with named IDs
$domElemsToRemove = [];
foreach ( $removals['ID'] as $itemToRemove ) {
$itemToRemoveNode = $doc->getElementById( $itemToRemove );
if ( $itemToRemoveNode ) {
$domElemsToRemove[] = $itemToRemoveNode;
}
}
$removed = array_merge( $removed, $this->removeElements( $domElemsToRemove ) );
// CSS Classes
$domElemsToRemove = [];
$xpath = new \DOMXPath( $doc );
foreach ( $removals['CLASS'] as $classToRemove ) {
$elements = $xpath->query( '//*[contains(@class, "' . $classToRemove . '")]' );
/** @var $element \DOMElement */
foreach ( $elements as $element ) {
$classes = $element->getAttribute( 'class' );
if ( \preg_match( "/\b$classToRemove\b/", $classes ) && $element->parentNode ) {
$domElemsToRemove[] = $element;
}
}
}
$removed = \array_merge( $removed, $this->removeElements( $domElemsToRemove ) );
// Tags with CSS Classes
foreach ( $removals['TAG_CLASS'] as $classToRemove ) {
$parts = explode( '.', $classToRemove );
$elements = $xpath->query(
'//' . $parts[0] . '[@class="' . $parts[1] . '"]'
);
$removed = array_merge( $removed, $this->removeElements( $elements ) );
}
return $removed;
}
/**
* Removes a list of elelments from DOMDocument
* @param array|\DOMNodeList $elements
* @return array Array of removed elements
*/
private function removeElements( $elements ) {
$list = $elements;
if ( $elements instanceof \DOMNodeList ) {
$list = [];
foreach ( $elements as $element ) {
$list[] = $element;
}
}
/** @var $element \DOMElement */
foreach ( $list as $element ) {
if ( $element->parentNode ) {
$element->parentNode->removeChild( $element );
}
}
return $list;
}
/**
* libxml in its usual pointlessness converts many chars to entities - this function
* perfoms a reverse conversion
* @param string $html
* @return string
*/
private function fixLibXML( $html ) {
// We don't include rules like '"' => '"' because entities had already been
// normalized by libxml. Using this function with input not sanitized by libxml is UNSAFE!
$replacements = [
'"' => '"',
'&' => '&',
'<' => '<',
'>' => '>',
];
$html = strtr( $html, $replacements );
// Just in case the conversion in getDoc() above used named
// entities that aren't known to html_entity_decode().
$html = \mb_convert_encoding( $html, 'UTF-8', 'HTML-ENTITIES' );
return $html;
}
/**
* Performs final transformations and returns resulting HTML. Note that if you want to call this
* both without an element and with an element you should call it without an element first. If you
* specify the $element in the method it'll change the underlying dom and you won't be able to get
* it back.
*
* @param \DOMElement|string|null $element ID of element to get HTML from or
* false to get it from the whole tree
* @return string Processed HTML
*/
public function getText( $element = null ) {
if ( $this->doc ) {
if ( $element !== null && !( $element instanceof \DOMElement ) ) {
$element = $this->doc->getElementById( $element );
}
if ( $element ) {
$body = $this->doc->getElementsByTagName( 'body' )->item( 0 );
$nodesArray = [];
foreach ( $body->childNodes as $node ) {
$nodesArray[] = $node;
}
foreach ( $nodesArray as $nodeArray ) {
$body->removeChild( $nodeArray );
}
$body->appendChild( $element );
}
$html = $this->doc->saveHTML();
$html = $this->fixLibXml( $html );
if ( PHP_EOL === "\r\n" ) {
// Cleanup for CRLF misprocessing of unknown origin on Windows.
$html = str_replace( '
', '', $html );
}
} else {
$html = $this->html;
}
// Remove stuff added by wrapHTML()
$html = \preg_replace( '/|^.*?|<\/body>.*$/s', '', $html );
$html = $this->onHtmlReady( $html );
if ( $this->elementsToFlatten ) {
$elements = \implode( '|', $this->elementsToFlatten );
$html = \preg_replace( "#]*>#is", '', $html );
}
return $html;
}
/**
* Helper function for parseItemsToRemove(). This function extracts the selector type
* and the raw name of a selector from a CSS-style selector string and assigns those
* values to parameters passed by reference. For example, if given '#toc' as the
* $selector parameter, it will assign 'ID' as the $type and 'toc' as the $rawName.
* @param string $selector CSS selector to parse
* @param string &$type The type of selector (ID, CLASS, TAG_CLASS, or TAG)
* @param string &$rawName The raw name of the selector
* @return bool Whether the selector was successfully recognised
* @throws \Exception
*/
protected function parseSelector( $selector, &$type, &$rawName ) {
if ( strpos( $selector, '.' ) === 0 ) {
$type = 'CLASS';
$rawName = substr( $selector, 1 );
} elseif ( strpos( $selector, '#' ) === 0 ) {
$type = 'ID';
$rawName = substr( $selector, 1 );
} elseif ( strpos( $selector, '.' ) !== 0 && strpos( $selector, '.' ) !== false ) {
$type = 'TAG_CLASS';
$rawName = $selector;
} elseif ( strpos( $selector, '[' ) === false && strpos( $selector, ']' ) === false ) {
$type = 'TAG';
$rawName = $selector;
} else {
throw new \Exception( __METHOD__ . "(): unrecognized selector '$selector'" );
}
return true;
}
/**
* Transforms CSS-style selectors into an internal representation suitable for
* processing by filterContent()
* @return array
*/
protected function parseItemsToRemove() {
$removals = [
'ID' => [],
'TAG' => [],
'CLASS' => [],
'TAG_CLASS' => [],
];
foreach ( $this->itemsToRemove as $itemToRemove ) {
$type = '';
$rawName = '';
if ( $this->parseSelector( $itemToRemove, $type, $rawName ) ) {
$removals[$type][] = $rawName;
}
}
if ( $this->removeMedia ) {
$removals['TAG'][] = 'img';
$removals['TAG'][] = 'audio';
$removals['TAG'][] = 'video';
}
return $removals;
}
}