According to php manual nor php://input neither $HTTP_RAW_POST_DATA work with multipart/form-data POST-requests.
"php://input allows you to read raw POST data. It is a less memory intensive alternative to $HTTP_RAW_POST_DATA and does not need any special php.ini directives. php://input is not available with enctype="multipart/form-data"."
How can I get raw data for multipart/form-data forms?