271da88127
Changed some old bugzilla links to new phabricator links in comments, test data and error message. This reduces the need for redirects from old bugzilla to new phabricator from our source code. Change-Id: Id98278e26ce31656295a23f3cadb536859c4caa5
378 lines
11 KiB
PHP
378 lines
11 KiB
PHP
<?php
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/**
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* Performs transformations of HTML by wrapping around libxml2 and working
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* around its countless bugs.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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* http://www.gnu.org/copyleft/gpl.html
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*
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* @file
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*/
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class HtmlFormatter {
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/**
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* @var DOMDocument
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*/
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private $doc;
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private $html;
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private $itemsToRemove = array();
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private $elementsToFlatten = array();
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protected $removeMedia = false;
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/**
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* Constructor
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*
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* @param string $html Text to process
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*/
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public function __construct( $html ) {
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$this->html = $html;
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}
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/**
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* Turns a chunk of HTML into a proper document
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* @param string $html
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* @return string
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*/
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public static function wrapHTML( $html ) {
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return '<!doctype html><html><head></head><body>' . $html . '</body></html>';
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}
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/**
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* Override this in descendant class to modify HTML after it has been converted from DOM tree
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* @param string $html HTML to process
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* @return string Processed HTML
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*/
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protected function onHtmlReady( $html ) {
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return $html;
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}
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/**
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* @return DOMDocument DOM to manipulate
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*/
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public function getDoc() {
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if ( !$this->doc ) {
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// DOMDocument::loadHTML apparently isn't very good with encodings, so
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// convert input to ASCII by encoding everything above 128 as entities.
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if ( function_exists( 'mb_convert_encoding' ) ) {
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$html = mb_convert_encoding( $this->html, 'HTML-ENTITIES', 'UTF-8' );
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} else {
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$html = preg_replace_callback( '/[\x{80}-\x{10ffff}]/u', function ( $m ) {
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return '&#' . UtfNormal\Utils::utf8ToCodepoint( $m[0] ) . ';';
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}, $this->html );
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}
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// Workaround for bug that caused spaces before references
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// to disappear during processing:
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// https://phabricator.wikimedia.org/T55086
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//
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// Please replace with a better fix if one can be found.
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$html = str_replace( ' <', ' <', $html );
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libxml_use_internal_errors( true );
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$loader = libxml_disable_entity_loader();
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$this->doc = new DOMDocument();
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$this->doc->strictErrorChecking = false;
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$this->doc->loadHTML( $html );
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libxml_disable_entity_loader( $loader );
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libxml_use_internal_errors( false );
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$this->doc->encoding = 'UTF-8';
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}
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return $this->doc;
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}
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/**
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* Sets whether images/videos/sounds should be removed from output
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* @param bool $flag
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*/
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public function setRemoveMedia( $flag = true ) {
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$this->removeMedia = $flag;
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}
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/**
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* Adds one or more selector of content to remove. A subset of CSS selector
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* syntax is supported:
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*
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* <tag>
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* <tag>.class
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* .<class>
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* #<id>
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*
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* @param array|string $selectors Selector(s) of stuff to remove
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*/
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public function remove( $selectors ) {
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$this->itemsToRemove = array_merge( $this->itemsToRemove, (array)$selectors );
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}
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/**
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* Adds one or more element name to the list to flatten (remove tag, but not its content)
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* Can accept undelimited regexes
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*
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* Note this interface may fail in surprising unexpected ways due to usage of regexes,
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* so should not be relied on for HTML markup security measures.
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*
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* @param array|string $elements Name(s) of tag(s) to flatten
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*/
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public function flatten( $elements ) {
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$this->elementsToFlatten = array_merge( $this->elementsToFlatten, (array)$elements );
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}
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/**
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* Instructs the formatter to flatten all tags
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*/
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public function flattenAllTags() {
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$this->flatten( '[?!]?[a-z0-9]+' );
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}
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/**
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* Removes content we've chosen to remove. The text of the removed elements can be
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* extracted with the getText method.
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* @return array Array of removed DOMElements
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*/
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public function filterContent() {
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$removals = $this->parseItemsToRemove();
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// Bail out early if nothing to do
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if ( array_reduce( $removals,
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function ( $carry, $item ) {
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return $carry && !$item;
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},
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true
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) ) {
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return array();
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}
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$doc = $this->getDoc();
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// Remove tags
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// You can't remove DOMNodes from a DOMNodeList as you're iterating
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// over them in a foreach loop. It will seemingly leave the internal
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// iterator on the foreach out of wack and results will be quite
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// strange. Though, making a queue of items to remove seems to work.
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$domElemsToRemove = array();
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foreach ( $removals['TAG'] as $tagToRemove ) {
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$tagToRemoveNodes = $doc->getElementsByTagName( $tagToRemove );
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foreach ( $tagToRemoveNodes as $tagToRemoveNode ) {
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if ( $tagToRemoveNode ) {
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$domElemsToRemove[] = $tagToRemoveNode;
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}
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}
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}
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$removed = $this->removeElements( $domElemsToRemove );
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// Elements with named IDs
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$domElemsToRemove = array();
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foreach ( $removals['ID'] as $itemToRemove ) {
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$itemToRemoveNode = $doc->getElementById( $itemToRemove );
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if ( $itemToRemoveNode ) {
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$domElemsToRemove[] = $itemToRemoveNode;
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}
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}
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$removed = array_merge( $removed, $this->removeElements( $domElemsToRemove ) );
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// CSS Classes
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$domElemsToRemove = array();
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$xpath = new DOMXPath( $doc );
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foreach ( $removals['CLASS'] as $classToRemove ) {
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$elements = $xpath->query( '//*[contains(@class, "' . $classToRemove . '")]' );
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/** @var $element DOMElement */
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foreach ( $elements as $element ) {
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$classes = $element->getAttribute( 'class' );
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if ( preg_match( "/\b$classToRemove\b/", $classes ) && $element->parentNode ) {
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$domElemsToRemove[] = $element;
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}
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}
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}
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$removed = array_merge( $removed, $this->removeElements( $domElemsToRemove ) );
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// Tags with CSS Classes
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foreach ( $removals['TAG_CLASS'] as $classToRemove ) {
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$parts = explode( '.', $classToRemove );
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$elements = $xpath->query(
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'//' . $parts[0] . '[@class="' . $parts[1] . '"]'
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);
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$removed = array_merge( $removed, $this->removeElements( $elements ) );
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}
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return $removed;
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}
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/**
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* Removes a list of elelments from DOMDocument
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* @param array|DOMNodeList $elements
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* @return array Array of removed elements
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*/
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private function removeElements( $elements ) {
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$list = $elements;
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if ( $elements instanceof DOMNodeList ) {
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$list = array();
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foreach ( $elements as $element ) {
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$list[] = $element;
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}
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}
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/** @var $element DOMElement */
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foreach ( $list as $element ) {
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if ( $element->parentNode ) {
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$element->parentNode->removeChild( $element );
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}
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}
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return $list;
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}
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/**
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* libxml in its usual pointlessness converts many chars to entities - this function
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* perfoms a reverse conversion
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* @param string $html
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* @return string
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*/
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private function fixLibXML( $html ) {
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static $replacements;
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if ( !$replacements ) {
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// We don't include rules like '"' => '&quot;' because entities had already been
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// normalized by libxml. Using this function with input not sanitized by libxml is UNSAFE!
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$replacements = new ReplacementArray( array(
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'"' => '&quot;',
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'&' => '&amp;',
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'<' => '&lt;',
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'>' => '&gt;',
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) );
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}
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$html = $replacements->replace( $html );
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if ( function_exists( 'mb_convert_encoding' ) ) {
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// Just in case the conversion in getDoc() above used named
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// entities that aren't known to html_entity_decode().
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$html = mb_convert_encoding( $html, 'UTF-8', 'HTML-ENTITIES' );
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} else {
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$html = html_entity_decode( $html, ENT_COMPAT, 'utf-8' );
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}
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return $html;
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}
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/**
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* Performs final transformations and returns resulting HTML. Note that if you want to call this
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* both without an element and with an element you should call it without an element first. If you
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* specify the $element in the method it'll change the underlying dom and you won't be able to get
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* it back.
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*
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* @param DOMElement|string|null $element ID of element to get HTML from or
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* false to get it from the whole tree
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* @return string Processed HTML
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*/
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public function getText( $element = null ) {
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if ( $this->doc ) {
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if ( $element !== null && !( $element instanceof DOMElement ) ) {
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$element = $this->doc->getElementById( $element );
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}
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if ( $element ) {
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$body = $this->doc->getElementsByTagName( 'body' )->item( 0 );
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$nodesArray = array();
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foreach ( $body->childNodes as $node ) {
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$nodesArray[] = $node;
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}
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foreach ( $nodesArray as $nodeArray ) {
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$body->removeChild( $nodeArray );
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}
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$body->appendChild( $element );
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}
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$html = $this->doc->saveHTML();
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$html = $this->fixLibXml( $html );
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if ( wfIsWindows() ) {
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// Cleanup for CRLF misprocessing of unknown origin on Windows.
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//
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// If this error continues in the future, please track it down in the
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// XML code paths if possible and fix there.
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$html = str_replace( ' ', '', $html );
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}
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} else {
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$html = $this->html;
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}
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// Remove stuff added by wrapHTML()
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$html = preg_replace( '/<!--.*?-->|^.*?<body>|<\/body>.*$/s', '', $html );
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$html = $this->onHtmlReady( $html );
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if ( $this->elementsToFlatten ) {
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$elements = implode( '|', $this->elementsToFlatten );
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$html = preg_replace( "#</?($elements)\\b[^>]*>#is", '', $html );
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}
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return $html;
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}
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/**
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* Helper function for parseItemsToRemove(). This function extracts the selector type
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* and the raw name of a selector from a CSS-style selector string and assigns those
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* values to parameters passed by reference. For example, if given '#toc' as the
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* $selector parameter, it will assign 'ID' as the $type and 'toc' as the $rawName.
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* @param string $selector CSS selector to parse
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* @param string $type The type of selector (ID, CLASS, TAG_CLASS, or TAG)
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* @param string $rawName The raw name of the selector
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* @return bool Whether the selector was successfully recognised
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* @throws MWException
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*/
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protected function parseSelector( $selector, &$type, &$rawName ) {
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if ( strpos( $selector, '.' ) === 0 ) {
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$type = 'CLASS';
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$rawName = substr( $selector, 1 );
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} elseif ( strpos( $selector, '#' ) === 0 ) {
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$type = 'ID';
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$rawName = substr( $selector, 1 );
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} elseif ( strpos( $selector, '.' ) !== 0 && strpos( $selector, '.' ) !== false ) {
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$type = 'TAG_CLASS';
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$rawName = $selector;
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} elseif ( strpos( $selector, '[' ) === false && strpos( $selector, ']' ) === false ) {
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$type = 'TAG';
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$rawName = $selector;
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} else {
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throw new MWException( __METHOD__ . "(): unrecognized selector '$selector'" );
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}
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return true;
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}
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/**
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* Transforms CSS-style selectors into an internal representation suitable for
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* processing by filterContent()
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* @return array
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*/
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protected function parseItemsToRemove() {
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$removals = array(
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'ID' => array(),
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'TAG' => array(),
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'CLASS' => array(),
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'TAG_CLASS' => array(),
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);
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foreach ( $this->itemsToRemove as $itemToRemove ) {
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$type = '';
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$rawName = '';
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if ( $this->parseSelector( $itemToRemove, $type, $rawName ) ) {
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$removals[$type][] = $rawName;
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}
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}
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if ( $this->removeMedia ) {
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$removals['TAG'][] = 'img';
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$removals['TAG'][] = 'audio';
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$removals['TAG'][] = 'video';
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}
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return $removals;
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}
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}
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