functions for convenient creation of standard http answers/exceptions
http_404_not_found(body = "Page not found", content_type = "text/plain",
...)http_405_method_not_allowed(body = "Method Not Allowed",
content_type = "text/plain", ...)
http_500_internal_server_error(body = "Internal Server Error",
content_type = "text/plain", ...)
http_520_unknown_error(body = "Unknown Error", content_type = "text/plain",
...)
reponse body
body content type
other parameters to create_response