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<?php |
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|
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if (!defined('WPO_VERSION')) die('No direct access allowed'); |
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|
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if (!class_exists('WPO_WebP_Alter_HTML')) : |
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|
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class WPO_WebP_Alter_HTML { |
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|
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private $tags = array('img', 'source', 'input', 'iframe', 'div', 'li', 'link', 'a', 'section', 'video'); |
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|
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/** |
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* Constructor |
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*/ |
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private function __construct() { |
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add_action('template_redirect', array($this, 'start'), 9999); |
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} |
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|
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/** |
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* Returns singleton instance |
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* |
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* @return WPO_WebP_Alter_HTML |
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*/ |
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public static function get_instance() { |
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static $_instance = null; |
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if (null === $_instance) { |
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$_instance = new self(); |
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} |
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return $_instance; |
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} |
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|
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/** |
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* Start to alter html in output buffer |
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*/ |
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public function start() { |
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if (!is_admin() || (defined('DOING_AJAX') && DOING_AJAX)) { |
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ob_start(array(__CLASS__, 'alter_html')); |
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} |
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} |
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|
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/** |
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* Alter html to change image related tags to specify webp images |
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* |
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* @param string $html - HTML document as string |
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* @return string |
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*/ |
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public function alter_html($html) { |
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|
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if (!$this->is_valid_html($html)) return $html; |
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|
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$this->maybe_include_simple_html_dom(); |
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|
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$dom = str_get_html($html, false, false, 'UTF-8', false); |
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|
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// MAX_FILE_SIZE is defined in simple_html_dom. |
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// For safety sake, we make sure it is defined before using |
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defined('MAX_FILE_SIZE') || define('MAX_FILE_SIZE', 600000); |
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|
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if (false === $dom) { |
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if (strlen($html) > MAX_FILE_SIZE) { |
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return '<!-- Alter HTML was skipped because the HTML is too big to process! ' . |
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'(limit is set to ' . MAX_FILE_SIZE . ' bytes) -->' . "\n" . $html; |
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} |
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return '<!-- Alter HTML was skipped because the helper library refused to process the html -->' . |
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"\n" . $html; |
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} |
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|
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// Replace attributes (src, srcset, data-src, etc) |
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foreach ($this->tags as $tag) { |
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$elems = $dom->find($tag); |
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foreach ($elems as $elem) { |
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$attributes = $elem->getAllAttributes(); |
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foreach ($attributes as $attr_name => $attr_value) { |
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if ($this->is_image_attribute($attr_name)) { |
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$elem->setAttribute($attr_name, $this->handle_attribute($attr_value)); |
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} |
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} |
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} |
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} |
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|
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return $dom->save(); |
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} |
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|
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/** |
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* Checks whether supplied string is a valid html document or not |
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* |
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* @param string $html - HTML document as string |
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* @return bool |
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*/ |
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private function is_valid_html($html) { |
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if (is_feed()) return false; |
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|
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// To prevent issue with `simple_html_dom` class |
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// Exit if it doesn't look like HTML |
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// https://github.com/rosell-dk/webp-express/issues/228 |
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if (!preg_match("#^\\s*<#", $html)) return false; |
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|
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if ('' == $html) return false; |
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return true; |
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} |
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|
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/** |
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* Include simple html dom script if not available |
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*/ |
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private function maybe_include_simple_html_dom() { |
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if (!function_exists('str_get_html')) { |
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require_once WPO_PLUGIN_MAIN_PATH . 'vendor/simplehtmldom/simplehtmldom/simple_html_dom.php'; |
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} |
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} |
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|
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/** |
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* Append image urls with `.webp` extension |
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* |
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* @param strinng $url - Image URL |
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* @return string |
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*/ |
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private function replace_url($url) { |
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return $url . '.webp'; |
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} |
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|
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/** |
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* If webp version for supplied image url is available then replace extension |
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* |
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* @param string $url - URL of image |
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* @return string |
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*/ |
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private function maybe_replace_url($url) { |
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if ($this->is_webp_version_available($url)) { |
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$url = $this->replace_url($url); |
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} |
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return $url; |
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} |
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|
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/** |
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* Modifies src attribute value, if needed |
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* |
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* @param string $attr_value |
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* @return string |
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*/ |
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private function handle_src($attr_value) { |
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return $this->maybe_replace_url($attr_value); |
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} |
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|
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/** |
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* Modified `srcset` attribute value, if needed |
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* |
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* @param string $attr_value |
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* @return string |
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*/ |
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private function handle_srcset($attr_value) { |
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// $attr_value is ie: <img data-x="1.jpg 1000w, 2.jpg"> |
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$srcset_arr = explode(',', $attr_value); |
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foreach ($srcset_arr as $i => $srcset_entry) { |
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// $srcset_entry is ie "image.jpg 520w", but can also lack width, ie just "image.jpg" |
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// it can also be ie "image.jpg 2x" |
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$srcset_entry = trim($srcset_entry); |
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$entry_parts = preg_split('/\s+/', $srcset_entry, 2); |
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if (count($entry_parts) == 2) { |
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list($src, $descriptors) = $entry_parts; |
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} else { |
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$src = $srcset_entry; |
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$descriptors = null; |
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} |
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|
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$url = $this->maybe_replace_url($src); |
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$srcset_arr[$i] = $url . (isset($descriptors) ? ' ' . $descriptors : ''); |
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} |
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return implode(', ', $srcset_arr); |
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} |
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|
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/** |
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* Decides whether given value is a `srcset` or not |
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* |
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* @return bool |
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*/ |
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private function looks_like_srcset($value) { |
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if (preg_match('#\s\d*(w|x)#', $value)) { |
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return true; |
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} |
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return false; |
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} |
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|
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/** |
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* Handle attribute value based on attribute name, src or srcset |
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* |
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* @return string |
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*/ |
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private function handle_attribute($value) { |
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if ($this->looks_like_srcset($value)) { |
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return $this->handle_srcset($value); |
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} |
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return $this->handle_src($value); |
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} |
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|
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/** |
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* Decide whether given attribute name is an image attribute or not |
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* |
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* @return bool |
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*/ |
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private function is_image_attribute($attr_name) { |
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return preg_match('#^(src|srcset|poster|(data-[^=]*(lazy|small|slide|img|large|src|thumb|source|set|bg-url)[^=]*))$#i', $attr_name); |
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} |
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|
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/** |
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* Does webp image file exists |
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* |
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* @param string $url |
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* @return boolean |
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*/ |
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private function is_webp_version_available($url) { |
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$filename = $this->get_file_path($url); |
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return file_exists($filename . '.webp'); |
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} |
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|
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/** |
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* Get the file path |
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* |
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* @param string $url |
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* @return string |
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*/ |
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private function get_file_path($url) { |
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if (is_multisite()) { |
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if (function_exists('get_main_site_id')) { |
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$site_id = get_main_site_id(); |
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} else { |
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$network = get_network(); |
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$site_id = $network->site_id; |
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} |
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switch_to_blog($site_id); |
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} |
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$upload_dir = wp_upload_dir(); |
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$uploads_url = trailingslashit($upload_dir['baseurl']); |
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$uploads_dir = trailingslashit($upload_dir['basedir']); |
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if (is_multisite()) { |
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restore_current_blog(); |
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} |
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$possible_urls = array( |
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WP_CONTENT_URL => WP_CONTENT_DIR, |
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WP_PLUGIN_URL => WP_PLUGIN_DIR, |
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$uploads_url => $uploads_dir, |
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get_template_directory_uri() => get_template_directory(), |
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includes_url() => preg_replace('/wp-content$/', trailingslashit('wp-includes'), WP_CONTENT_DIR), |
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); |
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$file = ''; |
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foreach ($possible_urls as $possible_url => $path) { |
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$pos = strpos($url, $possible_url); |
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if (false !== $pos) { |
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$file = substr_replace($url, $path, $pos, strlen($possible_url)); |
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break; |
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} |
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} |
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return $file; |
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} |
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} |
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|
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endif; |
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|
