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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_Self_Test')) : |
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|
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class WPO_WebP_Self_Test { |
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|
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/** |
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* Determines whether content type header has webp mime or not |
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* |
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* @param array $headers An array of headers |
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* |
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* @return bool |
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*/ |
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private function has_webp_mime($headers) { |
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return isset($headers['content-type']) && 0 === strcasecmp('image/webp', $headers['content-type']); |
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} |
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|
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/** |
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* Determines whether headers has `vary` header or not |
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* |
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* @param array $headers An array of headers |
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* |
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* @return bool |
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*/ |
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private function has_vary($headers) { |
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return isset($headers['vary']) && preg_match('/accept/i', $headers['vary']); |
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} |
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|
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/** |
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* Decided whether webp version is served or not |
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* |
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* @return bool |
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*/ |
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public function is_webp_served() { |
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$args = array( |
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'headers' => array( |
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'accept' => 'image/webp' |
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) |
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); |
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|
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$upload_dir = wp_upload_dir(); |
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$url = $upload_dir['baseurl']. '/wpo/images/wpo_logo_small.png'; |
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|
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$response = wp_remote_head($url, $args); |
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|
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if (is_wp_error($response)) return false; |
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if (200 != $response['response']['code']) return false; |
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|
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$headers = wp_remote_retrieve_headers($response); |
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if (method_exists($headers, 'getAll')) { |
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$headers = $headers->getAll(); |
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if ($this->has_webp_mime($headers) && $this->has_vary($headers)) { |
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return true; |
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} |
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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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* Returns singleton instance |
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* |
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* @return WPO_WebP_Self_Test |
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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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endif; |
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|
