305 lines
		
	
	
		
			9.2 KiB
		
	
	
	
		
			PHP
		
	
	
	
			
		
		
	
	
			305 lines
		
	
	
		
			9.2 KiB
		
	
	
	
		
			PHP
		
	
	
	
<?php namespace BookStack\Entities\Managers;
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use BookStack\Entities\Page;
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use DOMDocument;
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use DOMElement;
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use DOMNodeList;
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use DOMXPath;
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class PageContent
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{
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    protected $page;
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    /**
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     * PageContent constructor.
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     */
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    public function __construct(Page $page)
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    {
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        $this->page = $page;
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    }
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    /**
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     * Update the content of the page with new provided HTML.
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     */
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    public function setNewHTML(string $html)
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    {
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        $this->page->html = $this->formatHtml($html);
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        $this->page->text = $this->toPlainText();
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    }
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    /**
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     * Formats a page's html to be tagged correctly within the system.
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     */
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    protected function formatHtml(string $htmlText): string
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    {
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        if ($htmlText == '') {
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            return $htmlText;
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        }
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        libxml_use_internal_errors(true);
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        $doc = new DOMDocument();
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        $doc->loadHTML(mb_convert_encoding($htmlText, 'HTML-ENTITIES', 'UTF-8'));
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        $container = $doc->documentElement;
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        $body = $container->childNodes->item(0);
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        $childNodes = $body->childNodes;
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        // Set ids on top-level nodes
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        $idMap = [];
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        foreach ($childNodes as $index => $childNode) {
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            $this->setUniqueId($childNode, $idMap);
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        }
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        // Ensure no duplicate ids within child items
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        $xPath = new DOMXPath($doc);
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        $idElems = $xPath->query('//body//*//*[@id]');
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        foreach ($idElems as $domElem) {
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            $this->setUniqueId($domElem, $idMap);
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        }
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        // Generate inner html as a string
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        $html = '';
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        foreach ($childNodes as $childNode) {
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            $html .= $doc->saveHTML($childNode);
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        }
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        return $html;
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    }
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    /**
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     * Set a unique id on the given DOMElement.
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     * A map for existing ID's should be passed in to check for current existence.
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     * @param DOMElement $element
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     * @param array $idMap
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     */
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    protected function setUniqueId($element, array &$idMap)
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    {
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        if (get_class($element) !== 'DOMElement') {
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            return;
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        }
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        // Overwrite id if not a BookStack custom id
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        $existingId = $element->getAttribute('id');
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        if (strpos($existingId, 'bkmrk') === 0 && !isset($idMap[$existingId])) {
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            $idMap[$existingId] = true;
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            return;
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        }
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        // Create an unique id for the element
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        // Uses the content as a basis to ensure output is the same every time
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        // the same content is passed through.
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        $contentId = 'bkmrk-' . mb_substr(strtolower(preg_replace('/\s+/', '-', trim($element->nodeValue))), 0, 20);
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        $newId = urlencode($contentId);
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        $loopIndex = 0;
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        while (isset($idMap[$newId])) {
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            $newId = urlencode($contentId . '-' . $loopIndex);
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            $loopIndex++;
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        }
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        $element->setAttribute('id', $newId);
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        $idMap[$newId] = true;
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    }
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    /**
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     * Get a plain-text visualisation of this page.
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     */
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    protected function toPlainText(): string
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    {
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        $html = $this->render(true);
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        return html_entity_decode(strip_tags($html));
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    }
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    /**
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     * Render the page for viewing
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     */
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    public function render(bool $blankIncludes = false) : string
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    {
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        $content = $this->page->html;
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        if (!config('app.allow_content_scripts')) {
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            $content = $this->escapeScripts($content);
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        }
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        if ($blankIncludes) {
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            $content = $this->blankPageIncludes($content);
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        } else {
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            $content = $this->parsePageIncludes($content);
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        }
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        return $content;
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    }
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    /**
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     * Parse the headers on the page to get a navigation menu
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     */
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    public function getNavigation(string $htmlContent): array
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    {
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        if (empty($htmlContent)) {
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            return [];
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        }
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        libxml_use_internal_errors(true);
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        $doc = new DOMDocument();
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        $doc->loadHTML(mb_convert_encoding($htmlContent, 'HTML-ENTITIES', 'UTF-8'));
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        $xPath = new DOMXPath($doc);
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        $headers = $xPath->query("//h1|//h2|//h3|//h4|//h5|//h6");
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        return $headers ? $this->headerNodesToLevelList($headers) : [];
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    }
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    /**
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     * Convert a DOMNodeList into an array of readable header attributes
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     * with levels normalised to the lower header level.
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     */
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    protected function headerNodesToLevelList(DOMNodeList $nodeList): array
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    {
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        $tree = collect($nodeList)->map(function ($header) {
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            $text = trim(str_replace("\xc2\xa0", '', $header->nodeValue));
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            $text = mb_substr($text, 0, 100);
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            return [
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                'nodeName' => strtolower($header->nodeName),
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                'level' => intval(str_replace('h', '', $header->nodeName)),
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                'link' => '#' . $header->getAttribute('id'),
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                'text' => $text,
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            ];
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        })->filter(function ($header) {
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            return mb_strlen($header['text']) > 0;
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        });
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        // Shift headers if only smaller headers have been used
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        $levelChange = ($tree->pluck('level')->min() - 1);
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        $tree = $tree->map(function ($header) use ($levelChange) {
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            $header['level'] -= ($levelChange);
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            return $header;
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        });
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        return $tree->toArray();
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    }
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    /**
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     * Remove any page include tags within the given HTML.
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     */
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    protected function blankPageIncludes(string $html) : string
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    {
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        return preg_replace("/{{@\s?([0-9].*?)}}/", '', $html);
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    }
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    /**
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     * Parse any include tags "{{@<page_id>#section}}" to be part of the page.
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     */
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    protected function parsePageIncludes(string $html) : string
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    {
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        $matches = [];
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        preg_match_all("/{{@\s?([0-9].*?)}}/", $html, $matches);
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        foreach ($matches[1] as $index => $includeId) {
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            $fullMatch = $matches[0][$index];
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            $splitInclude = explode('#', $includeId, 2);
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            // Get page id from reference
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            $pageId = intval($splitInclude[0]);
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            if (is_nan($pageId)) {
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                continue;
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            }
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            // Find page and skip this if page not found
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            $matchedPage = Page::visible()->find($pageId);
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            if ($matchedPage === null) {
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                $html = str_replace($fullMatch, '', $html);
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                continue;
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            }
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            // If we only have page id, just insert all page html and continue.
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            if (count($splitInclude) === 1) {
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                $html = str_replace($fullMatch, $matchedPage->html, $html);
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                continue;
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            }
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            // Create and load HTML into a document
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            $innerContent = $this->fetchSectionOfPage($matchedPage, $splitInclude[1]);
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            $html = str_replace($fullMatch, trim($innerContent), $html);
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        }
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        return $html;
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    }
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    /**
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     * Fetch the content from a specific section of the given page.
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     */
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    protected function fetchSectionOfPage(Page $page, string $sectionId): string
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    {
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        $topLevelTags = ['table', 'ul', 'ol'];
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        $doc = new DOMDocument();
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        libxml_use_internal_errors(true);
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        $doc->loadHTML(mb_convert_encoding('<body>'.$page->html.'</body>', 'HTML-ENTITIES', 'UTF-8'));
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        // Search included content for the id given and blank out if not exists.
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        $matchingElem = $doc->getElementById($sectionId);
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        if ($matchingElem === null) {
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            return '';
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        }
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        // Otherwise replace the content with the found content
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        // Checks if the top-level wrapper should be included by matching on tag types
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        $innerContent = '';
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        $isTopLevel = in_array(strtolower($matchingElem->nodeName), $topLevelTags);
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        if ($isTopLevel) {
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            $innerContent .= $doc->saveHTML($matchingElem);
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        } else {
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            foreach ($matchingElem->childNodes as $childNode) {
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                $innerContent .= $doc->saveHTML($childNode);
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            }
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        }
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        libxml_clear_errors();
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        return $innerContent;
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    }
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    /**
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     * Escape script tags within HTML content.
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     */
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    protected function escapeScripts(string $html) : string
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    {
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        if (empty($html)) {
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            return $html;
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        }
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        libxml_use_internal_errors(true);
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        $doc = new DOMDocument();
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        $doc->loadHTML(mb_convert_encoding($html, 'HTML-ENTITIES', 'UTF-8'));
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        $xPath = new DOMXPath($doc);
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        // Remove standard script tags
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        $scriptElems = $xPath->query('//script');
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        foreach ($scriptElems as $scriptElem) {
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            $scriptElem->parentNode->removeChild($scriptElem);
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        }
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        // Remove data or JavaScript iFrames
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        $badIframes = $xPath->query('//*[contains(@src, \'data:\')] | //*[contains(@src, \'javascript:\')] | //*[@srcdoc]');
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        foreach ($badIframes as $badIframe) {
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            $badIframe->parentNode->removeChild($badIframe);
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        }
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        // Remove 'on*' attributes
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        $onAttributes = $xPath->query('//@*[starts-with(name(), \'on\')]');
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        foreach ($onAttributes as $attr) {
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            /** @var \DOMAttr $attr*/
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            $attrName = $attr->nodeName;
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            $attr->parentNode->removeAttribute($attrName);
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        }
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        $html = '';
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        $topElems = $doc->documentElement->childNodes->item(0)->childNodes;
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        foreach ($topElems as $child) {
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            $html .= $doc->saveHTML($child);
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        }
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        return $html;
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    }
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}
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