mirror of
https://github.com/RSS-Bridge/rss-bridge.git
synced 2025-04-03 16:19:45 +00:00
26a4c255d3
* [html] convertLazyLoading: Add parseSrcset() Add srcset parser closer to the specifications * [html] code linting * [html] parseSrcset: Add type hints, check preg_match_all
477 lines
17 KiB
PHP
477 lines
17 KiB
PHP
<?php
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/**
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* Render template using base.html.php as base
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*/
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function render(string $template, array $context = []): string
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{
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if ($template === 'base.html.php') {
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throw new \Exception('Do not render base.html.php into itself');
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}
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$context['messages'] = $context['messages'] ?? [];
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if (Configuration::getConfig('system', 'message')) {
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$context['messages'][] = [
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'body' => Configuration::getConfig('system', 'message'),
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'level' => 'info',
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];
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}
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if (Debug::isEnabled()) {
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$debugModeWhitelist = Configuration::getConfig('system', 'debug_mode_whitelist') ?: [];
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if ($debugModeWhitelist === []) {
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$context['messages'][] = [
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'body' => 'Warning : Debug mode is active from any location, make sure only you can access RSS-Bridge.',
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'level' => 'error'
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];
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} else {
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$context['messages'][] = [
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'body' => 'Warning : Debug mode is active from your IP address, your requests will bypass the cache.',
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'level' => 'warning'
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];
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}
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}
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$context['page'] = render_template($template, $context);
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return render_template('base.html.php', $context);
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}
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/**
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* Render php template with context
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*
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* DO NOT PASS USER INPUT IN $template OR $context (keys!)
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*/
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function render_template(string $template, array $context = []): string
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{
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if (isset($context['template'])) {
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throw new \Exception("Don't use `template` as a context key");
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}
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$templateFilepath = __DIR__ . '/../templates/' . $template;
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extract($context);
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ob_start();
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try {
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if (is_file($template)) {
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require $template;
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} elseif (is_file($templateFilepath)) {
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require $templateFilepath;
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} else {
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throw new \Exception(sprintf('Unable to find template `%s`', $template));
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}
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} catch (\Throwable $e) {
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ob_end_clean();
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throw $e;
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}
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return ob_get_clean();
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}
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/**
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* Escape for html context
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*/
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function e(string $s): string
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{
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return htmlspecialchars($s, ENT_QUOTES | ENT_SUBSTITUTE, 'UTF-8');
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}
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/**
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* Explicitly don't escape
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*/
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function raw(string $s): string
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{
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return $s;
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}
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function truncate(string $s, int $length = 150, $marker = '...'): string
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{
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$s = trim($s);
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if (mb_strlen($s) <= $length) {
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return $s;
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}
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return mb_substr($s, 0, $length) . $marker;
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}
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/**
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* Removes unwanted tags from a given HTML text.
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*
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* @param string $html The HTML text to sanitize.
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* @param array $tags_to_remove A list of tags to remove from the DOM.
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* @param array $attributes_to_keep A list of attributes to keep on tags (other
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* attributes are removed).
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* @param array $text_to_keep A list of tags where the innertext replaces the tag
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* (i.e. `<p>Hello World!</p>` becomes `Hello World!`).
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* @return object A simplehtmldom object of the remaining contents.
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*
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* @todo Check if this implementation is still necessary, because simplehtmldom
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* already removes some of the tags (search for `remove_noise` in simple_html_dom.php).
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*/
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function sanitize(
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$html,
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$tags_to_remove = ['script', 'iframe', 'input', 'form'],
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$attributes_to_keep = ['title', 'href', 'src'],
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$text_to_keep = []
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) {
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$htmlContent = str_get_html($html);
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foreach ($htmlContent->find('*') as $element) {
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if (in_array($element->tag, $text_to_keep)) {
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$element->outertext = $element->plaintext;
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} elseif (in_array($element->tag, $tags_to_remove)) {
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$element->outertext = '';
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} else {
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foreach ($element->getAllAttributes() as $attributeName => $attribute) {
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if (!in_array($attributeName, $attributes_to_keep)) {
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$element->removeAttribute($attributeName);
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}
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}
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}
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}
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return $htmlContent;
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}
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function break_annoying_html_tags(string $html): string
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{
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$html = str_replace('<script', '<‌script', $html); // Disable scripts, but leave them visible.
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$html = str_replace('<iframe', '<‌iframe', $html);
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$html = str_replace('<link', '<‌link', $html);
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// We leave alone object and embed so that videos can play in RSS readers.
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return $html;
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}
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/**
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* Replace background by image
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*
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* Replaces tags with styles of `backgroud-image` by `<img />` tags.
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*
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* For example:
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*
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* ```HTML
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* <html>
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* <body style="background-image: url('bgimage.jpg');">
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* <h1>Hello world!</h1>
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* </body>
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* </html>
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* ```
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*
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* results in this output:
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*
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* ```HTML
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* <html>
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* <img style="display:block;" src="bgimage.jpg" />
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* </html>
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* ```
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*
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* @param string $htmlContent The HTML content
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* @return string The HTML content with all ocurrences replaced
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*/
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function backgroundToImg($htmlContent)
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{
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$regex = '/background-image[ ]{0,}:[ ]{0,}url\([\'"]{0,}(.*?)[\'"]{0,}\)/';
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$htmlContent = str_get_html($htmlContent);
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foreach ($htmlContent->find('*') as $element) {
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if (preg_match($regex, $element->style, $matches) > 0) {
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$element->outertext = '<img style="display:block;" src="' . $matches[1] . '" />';
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}
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}
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return $htmlContent;
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}
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/**
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* Convert relative links in HTML into absolute links
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*
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* This function is based on `php-urljoin`.
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*
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* @link https://github.com/plaidfluff/php-urljoin php-urljoin
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*
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* @param string|object $dom The HTML content. Supports HTML objects or string objects
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* @param string $url Fully qualified URL to the page containing relative links
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* @return string|object Content with fixed URLs.
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*/
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function defaultLinkTo($dom, $url)
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{
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if ($dom === '') {
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return $url;
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}
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$string_convert = false;
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if (is_string($dom)) {
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$string_convert = true;
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$dom = str_get_html($dom);
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}
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// Use long method names for compatibility with simple_html_dom and DOMDocument
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// Work around bug in simple_html_dom->getElementsByTagName
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if ($dom instanceof simple_html_dom) {
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$findByTag = function ($name) use ($dom) {
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return $dom->getElementsByTagName($name, null);
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};
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} else {
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$findByTag = function ($name) use ($dom) {
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return $dom->getElementsByTagName($name);
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};
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}
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foreach ($findByTag('img') as $image) {
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$image->setAttribute('src', urljoin($url, $image->getAttribute('src')));
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}
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foreach ($findByTag('a') as $anchor) {
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$anchor->setAttribute('href', urljoin($url, $anchor->getAttribute('href')));
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}
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// Will never be true for DOMDocument
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if ($string_convert) {
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$dom = $dom->outertext;
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}
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return $dom;
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}
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/**
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* Parse a srcset HTML attribute value and return size => URL mappings
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* Srcset contains a list of image URLs with associated size specified as size (e.g. 1024w) or scale (e.g. 2x)
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* The web browser should pick the most appropriate image depending on screen size and/or pixel density
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*
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* This function takes a srcset string such as the following:
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* header640.png 640w, header960.png 960w, header1024.png 1024w
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*
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* Returns an array such as the following:
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* [
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* '640w' => 'header640.png',
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* '960w' => 'header960.png',
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* '1024w' => 'header1024.png'
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* ]
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*
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* @param string $srcset Content of srcset html attribute
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* @param bool $return_largest_url Instead of returning an array, return URL for the largest entry
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* @return array|string Content of srcset attribute as { size => url } array, or largest entry URL if requested
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*/
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function parseSrcset(string $srcset, bool $return_largest_url = false)
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{
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// The srcset format is more tricky to parse that it seems:
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// URLs may contain commas, and space after comma is not mandatory, so the following is valid:
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// image.png?resize=640,640 640w,image.png?resize=960,960 960w,image.png?resize=1024,1024 1024w
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// Since splitting by space or comma will not work, there is a precise algorithm to parse srcset attribute:
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// https://html.spec.whatwg.org/multipage/images.html#parse-a-srcset-attribute
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// To summarize, each srcset entry has the following format:
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// 1. Leading spaces and comma. Zero or more spaces, zero or at most one comma
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// 2. Any amount of characters up to the next whitespace (space, tab, newline...): This is the URL
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// 3. A nonnegative number followed by lowercase w, x or h: This is the image size
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// We parse the srcset entries using a regex to mimick the above parser/tokenizer behavior.
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$preg_status = preg_match_all('/[\s]*,?[\s]*([^\s]+)\s+([0-9]+[wxh])/', $srcset, $matches);
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$entries = [];
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if ($preg_status !== false && $preg_status > 0) {
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foreach ($matches[1] as $index => $url) {
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if (array_key_exists($index, $matches[2])) {
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$size = $matches[2][$index];
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$entries[$size] = html_entity_decode($url);
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}
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}
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}
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if ($return_largest_url) {
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$largest_image_url = null;
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$largest_image_size = -1;
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foreach ($entries as $size => $url) {
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$size_int = intval(substr($size, 0, strlen($size) - 1));
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if ($size_int > $largest_image_size) {
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$largest_image_size = $size_int;
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$largest_image_url = $url;
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}
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}
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return $largest_image_url;
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} else {
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return $entries;
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}
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}
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/**
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* Convert lazy-loading images and frames (video embeds) into static elements
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*
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* This function looks for lazy-loading attributes such as 'data-src' and converts
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* them back to regular ones such as 'src', making them loadable in RSS readers.
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* It also converts <picture> elements to plain <img> elements.
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*
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* @param string|object $content The HTML content. Supports HTML objects or string objects
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* @return string|object Content with fixed image/frame URLs (same type as input).
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*/
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function convertLazyLoading($dom)
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{
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$string_convert = false;
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if (is_string($dom)) {
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$string_convert = true;
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$dom = str_get_html($dom);
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}
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// Process standalone images, embeds and picture sources
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foreach ($dom->find('img, iframe, source') as $img) {
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if (!empty($img->getAttribute('data-src'))) {
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$img->src = $img->getAttribute('data-src');
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} elseif (!empty($img->getAttribute('data-srcset'))) {
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$img->src = parseSrcset($img->getAttribute('data-srcset'));
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} elseif (!empty($img->getAttribute('data-lazy-src'))) {
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$img->src = $img->getAttribute('data-lazy-src');
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} elseif (!empty($img->getAttribute('data-orig-file'))) {
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$img->src = $img->getAttribute('data-orig-file');
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} elseif (!empty($img->getAttribute('srcset'))) {
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$img->src = parseSrcset($img->getAttribute('srcset'));
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} else {
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continue; // Proceed to next element without removing attributes
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}
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// Remove data attributes, no longer necessary
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foreach ($img->getAllAttributes() as $attr => $val) {
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if (str_starts_with($attr, 'data-')) {
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$img->removeAttribute($attr);
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}
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}
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// Remove other attributes that may be processed by the client
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foreach (['loading', 'decoding', 'srcset'] as $attr) {
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if ($img->hasAttribute($attr)) {
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$img->removeAttribute($attr);
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}
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}
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}
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// Convert complex HTML5 pictures to plain, standalone images
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// <img> and <source> tags already have their "src" attribute set at this point,
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// so we replace the whole <picture> with a standalone <img> from within the <picture>
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foreach ($dom->find('picture') as $picture) {
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$img = $picture->find('img, source', 0);
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if (!empty($img)) {
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if ($img->tag == 'source') {
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$img->tag = 'img';
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}
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// Adding/removing node would change its position inside the parent element,
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// So instead we rewrite the node in-place through the outertext attribute
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$picture->outertext = $img->outertext;
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}
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}
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// If the expected return type is object, reload the DOM to make sure
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// all $picture->outertext rewritten above are converted back to objects
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$dom = $dom->outertext;
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if (!$string_convert) {
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$dom = str_get_html($dom);
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}
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return $dom;
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}
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/**
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* Extract the first part of a string matching the specified start and end delimiters
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*
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* @param string $string Input string, e.g. `<div>Post author: John Doe</div>`
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* @param string $start Start delimiter, e.g. `author: `
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* @param string $end End delimiter, e.g. `<`
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* @return string|bool Extracted string, e.g. `John Doe`, or false if the
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* delimiters were not found.
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*/
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function extractFromDelimiters($string, $start, $end)
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{
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if (strpos($string, $start) !== false) {
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$section_retrieved = substr($string, strpos($string, $start) + strlen($start));
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$section_retrieved = substr($section_retrieved, 0, strpos($section_retrieved, $end));
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return $section_retrieved;
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}
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return false;
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}
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/**
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* Remove one or more part(s) of a string using a start and end delmiters
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*
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* @param string $string Input string, e.g. `foo<script>superscript()</script>bar`
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* @param string $start Start delimiter, e.g. `<script>`
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* @param string $end End delimiter, e.g. `</script>`
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* @return string Cleaned string, e.g. `foobar`
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*/
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function stripWithDelimiters($string, $start, $end)
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{
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while (strpos($string, $start) !== false) {
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$section_to_remove = substr($string, strpos($string, $start));
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$section_to_remove = substr($section_to_remove, 0, strpos($section_to_remove, $end) + strlen($end));
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$string = str_replace($section_to_remove, '', $string);
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}
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return $string;
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}
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/**
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* Remove HTML sections containing one or more sections using the same HTML tag
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*
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* @param string $string Input string, e.g. `foo<div class="ads"><div>ads</div>ads</div>bar`
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* @param string $tag_name Name of the HTML tag, e.g. `div`
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* @param string $tag_start Start of the HTML tag to remove, e.g. `<div class="ads">`
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* @return string Cleaned String, e.g. `foobar`
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*
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* This function works by locating the desired tag start, then finding the appropriate
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* end by counting opening and ending tags until the amount of open tags reaches zero:
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*
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* ```
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* Amount of open tags:
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* 1 2 1 0
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* |---------------||---| |----| |----|
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* <div class="ads"><div>ads</div>ads</div>bar
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* | <-------- Section to remove -------> |
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* ```
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*/
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function stripRecursiveHTMLSection($string, $tag_name, $tag_start)
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{
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$open_tag = '<' . $tag_name;
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$close_tag = '</' . $tag_name . '>';
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$close_tag_length = strlen($close_tag);
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// Make sure the provided $tag_start argument matches the provided $tag_name argument
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if (strpos($tag_start, $open_tag) === 0) {
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// While tag_start is present, there is at least one remaining section to remove
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while (strpos($string, $tag_start) !== false) {
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// In order to locate the end of the section, we attempt each closing tag until we find the right one
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// We know we found the right one when the amount of "<tag" is the same as amount of "</tag"
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// When the attempted "</tag" is not the correct one, we increase $search_offset to skip it
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// and retry unless $max_recursion is reached (prevents infinite loop on malformed HTML)
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$max_recursion = 100;
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$section_to_remove = null;
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$section_start = strpos($string, $tag_start);
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$search_offset = $section_start;
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do {
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$max_recursion--;
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// Move on to the next occurrence of "</tag"
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$section_end = strpos($string, $close_tag, $search_offset);
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$search_offset = $section_end + $close_tag_length;
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// If the next "</tag" is the correct one, then this is the section we must remove:
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$section_to_remove = substr($string, $section_start, $section_end - $section_start + $close_tag_length);
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// Count amount of "<tag" and "</tag" in the section to remove
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$open_tag_count = substr_count($section_to_remove, $open_tag);
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$close_tag_count = substr_count($section_to_remove, $close_tag);
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} while ($open_tag_count > $close_tag_count && $max_recursion > 0);
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// We exited the loop, let's remove the section
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$string = str_replace($section_to_remove, '', $string);
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}
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}
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return $string;
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}
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/**
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* Convert Markdown into HTML with Parsedown.
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*
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* @link https://parsedown.org/ Parsedown
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*
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* @param string $string Input string in Markdown format
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* @param array $config Parsedown options to control output
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* @return string output string in HTML format
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*/
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function markdownToHtml($string, $config = [])
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{
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$Parsedown = new Parsedown();
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foreach ($config as $option => $value) {
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if ($option === 'breaksEnabled') {
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$Parsedown->setBreaksEnabled($value);
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} elseif ($option === 'markupEscaped') {
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$Parsedown->setMarkupEscaped($value);
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} elseif ($option === 'urlsLinked') {
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$Parsedown->setUrlsLinked($value);
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} else {
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throw new \InvalidArgumentException("Invalid Parsedown option \"$option\"");
|
|
}
|
|
}
|
|
return $Parsedown->text($string);
|
|
}
|