Fix: Send Content-Length header to client from top Exception handler The top exception handler in run_cgi wasn't sending the Content-Length header for the error message. This resulted in a hung client. Probably wasn't an issue with http 1.0, but when using 1.1 it's required.

try:
    # Python 3+.
    from xmlrpc import client, server
    server.SimpleXMLRPCDispatcher
except (ImportError, AttributeError):
    # Python 2.
    import xmlrpclib as client  # noqa: F401
    import SimpleXMLRPCServer as server