264 lines
7.7 KiB
PHP
Executable File
264 lines
7.7 KiB
PHP
Executable File
<?php
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namespace Pelago\Emogrifier\HtmlProcessor;
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/**
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* Base class for HTML processor that e.g., can remove, add or modify nodes or attributes.
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*
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* The "vanilla" subclass is the HtmlNormalizer.
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*
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* @internal This class currently is a new technology preview, and its API is still in flux. Don't use it in production.
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*
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* @author Oliver Klee <github@oliverklee.de>
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*/
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abstract class AbstractHtmlProcessor
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{
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/**
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* @var string
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*/
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const DEFAULT_DOCUMENT_TYPE = '<!DOCTYPE html>';
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/**
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* @var string
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*/
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const CONTENT_TYPE_META_TAG = '<meta http-equiv="Content-Type" content="text/html; charset=utf-8">';
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/**
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* @var string Regular expression part to match tag names that PHP's DOMDocument implementation is not aware are
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* self-closing. These are mostly HTML5 elements, but for completeness <command> (obsolete) and <keygen>
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* (deprecated) are also included.
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*
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* @see https://bugs.php.net/bug.php?id=73175
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*/
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const PHP_UNRECOGNIZED_VOID_TAGNAME_MATCHER = '(?:command|embed|keygen|source|track|wbr)';
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/**
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* @var \DOMDocument
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*/
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protected $domDocument = null;
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/**
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* @param string $unprocessedHtml raw HTML, must be UTF-encoded, must not be empty
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*
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* @throws \InvalidArgumentException if $unprocessedHtml is anything other than a non-empty string
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*/
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public function __construct($unprocessedHtml)
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{
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if (!\is_string($unprocessedHtml)) {
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throw new \InvalidArgumentException('The provided HTML must be a string.', 1515459744);
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}
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if ($unprocessedHtml === '') {
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throw new \InvalidArgumentException('The provided HTML must not be empty.', 1515763647);
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}
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$this->setHtml($unprocessedHtml);
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}
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/**
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* Sets the HTML to process.
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*
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* @param string $html the HTML to process, must be UTF-8-encoded
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*
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* @return void
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*/
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private function setHtml($html)
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{
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$this->createUnifiedDomDocument($html);
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}
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/**
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* Provides access to the internal DOMDocument representation of the HTML in its current state.
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*
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* @return \DOMDocument
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*/
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public function getDomDocument()
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{
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return $this->domDocument;
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}
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/**
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* Renders the normalized and processed HTML.
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*
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* @return string
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*/
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public function render()
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{
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$htmlWithPossibleErroneousClosingTags = $this->domDocument->saveHTML();
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return $this->removeSelfClosingTagsClosingTags($htmlWithPossibleErroneousClosingTags);
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}
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/**
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* Renders the content of the BODY element of the normalized and processed HTML.
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*
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* @return string
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*/
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public function renderBodyContent()
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{
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$htmlWithPossibleErroneousClosingTags = $this->domDocument->saveHTML($this->getBodyElement());
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$bodyNodeHtml = $this->removeSelfClosingTagsClosingTags($htmlWithPossibleErroneousClosingTags);
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return \str_replace(['<body>', '</body>'], '', $bodyNodeHtml);
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}
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/**
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* Eliminates any invalid closing tags for void elements from the given HTML.
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*
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* @param string $html
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*
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* @return string
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*/
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private function removeSelfClosingTagsClosingTags($html)
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{
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return \preg_replace('%</' . static::PHP_UNRECOGNIZED_VOID_TAGNAME_MATCHER . '>%', '', $html);
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}
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/**
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* Returns the BODY element.
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*
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* This method assumes that there always is a BODY element.
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*
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* @return \DOMElement
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*/
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private function getBodyElement()
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{
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return $this->domDocument->getElementsByTagName('body')->item(0);
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}
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/**
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* Creates a DOM document from the given HTML and stores it in $this->domDocument.
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*
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* The DOM document will always have a BODY element and a document type.
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*
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* @param string $html
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*
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* @return void
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*/
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private function createUnifiedDomDocument($html)
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{
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$this->createRawDomDocument($html);
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$this->ensureExistenceOfBodyElement();
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}
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/**
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* Creates a DOMDocument instance from the given HTML and stores it in $this->domDocument.
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*
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* @param string $html
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*
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* @return void
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*/
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private function createRawDomDocument($html)
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{
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$domDocument = new \DOMDocument();
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$domDocument->strictErrorChecking = false;
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$domDocument->formatOutput = true;
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$libXmlState = \libxml_use_internal_errors(true);
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$domDocument->loadHTML($this->prepareHtmlForDomConversion($html));
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\libxml_clear_errors();
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\libxml_use_internal_errors($libXmlState);
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$this->domDocument = $domDocument;
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}
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/**
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* Returns the HTML with added document type, Content-Type meta tag, and self-closing slashes, if needed,
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* ensuring that the HTML will be good for creating a DOM document from it.
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*
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* @param string $html
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*
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* @return string the unified HTML
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*/
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private function prepareHtmlForDomConversion($html)
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{
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$htmlWithSelfClosingSlashes = $this->ensurePhpUnrecognizedSelfClosingTagsAreXml($html);
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$htmlWithDocumentType = $this->ensureDocumentType($htmlWithSelfClosingSlashes);
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return $this->addContentTypeMetaTag($htmlWithDocumentType);
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}
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/**
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* Makes sure that the passed HTML has a document type.
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*
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* @param string $html
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*
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* @return string HTML with document type
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*/
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private function ensureDocumentType($html)
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{
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$hasDocumentType = \stripos($html, '<!DOCTYPE') !== false;
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if ($hasDocumentType) {
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return $html;
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}
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return static::DEFAULT_DOCUMENT_TYPE . $html;
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}
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/**
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* Adds a Content-Type meta tag for the charset.
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*
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* This method also ensures that there is a HEAD element.
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*
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* @param string $html
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*
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* @return string the HTML with the meta tag added
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*/
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private function addContentTypeMetaTag($html)
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{
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$hasContentTypeMetaTag = \stripos($html, 'Content-Type') !== false;
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if ($hasContentTypeMetaTag) {
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return $html;
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}
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// We are trying to insert the meta tag to the right spot in the DOM.
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// If we just prepended it to the HTML, we would lose attributes set to the HTML tag.
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$hasHeadTag = \stripos($html, '<head') !== false;
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$hasHtmlTag = \stripos($html, '<html') !== false;
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if ($hasHeadTag) {
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$reworkedHtml = \preg_replace('/<head(.*?)>/i', '<head$1>' . static::CONTENT_TYPE_META_TAG, $html);
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} elseif ($hasHtmlTag) {
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$reworkedHtml = \preg_replace(
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'/<html(.*?)>/i',
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'<html$1><head>' . static::CONTENT_TYPE_META_TAG . '</head>',
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$html
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);
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} else {
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$reworkedHtml = static::CONTENT_TYPE_META_TAG . $html;
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}
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return $reworkedHtml;
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}
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/**
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* Makes sure that any self-closing tags not recognized as such by PHP's DOMDocument implementation have a
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* self-closing slash.
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*
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* @param string $html
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*
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* @return string HTML with problematic tags converted.
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*/
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private function ensurePhpUnrecognizedSelfClosingTagsAreXml($html)
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{
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return \preg_replace(
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'%<' . static::PHP_UNRECOGNIZED_VOID_TAGNAME_MATCHER . '\\b[^>]*+(?<!/)(?=>)%',
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'$0/',
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$html
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);
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}
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/**
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* Checks that $this->domDocument has a BODY element and adds it if it is missing.
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*
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* @return void
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*/
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private function ensureExistenceOfBodyElement()
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{
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if ($this->domDocument->getElementsByTagName('body')->item(0) !== null) {
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return;
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}
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$htmlElement = $this->domDocument->getElementsByTagName('html')->item(0);
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$htmlElement->appendChild($this->domDocument->createElement('body'));
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}
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}
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