}
/**
+ * Generate a data URL.
+ */
+ public static function generateDataURL($url) {
+ $supported_content_types = [
+ "image/gif",
+ "image/jpeg",
+ "image/png",
+ ];
+
+ $url_info = Tweeper::getUrlInfo($url);
+ if (FALSE === $url_info) {
+ trigger_error("Failed to retrieve info for URL: " . $url, E_USER_WARNING);
+ return '';
+ }
+
+ $supported = in_array($url_info['content_type'], $supported_content_types);
+ if (!$supported) {
+ trigger_error("Unsupported data URL type \"" . $url_info['content_type'] . "\" for URL: " . $url_info['url'], E_USER_WARNING);
+ return '';
+ }
+
+ $base64Data = base64_encode(file_get_contents($url));
+ $dataURL = 'data: ' . $url_info['content_type'] . ';base64,' . $base64Data;
+
+ return $dataURL;
+ }
+
+ /**
* Mimic the message from libxml.c::php_libxml_ctx_error_level()
*/
private static function logXmlError($error) {