BookStack/app/Entities/Managers/PageContent.php

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