FilenameWithUUID returns given filename with a UUID as prefix Format: "uuidprefix_filename.extension".

IsValidUUID checks if given string is a valid UUID string.

SizeToString converts number of bytes to binary prefix (Kibibyte, Mebibyte, ...) Returns number of bytes formated as [dddd.dcc] d:digit, c:char.

WriteJSON encodes values and sends them over ResponseWriter with status code Returns error if encoding fails.