I'm getting a traceback when creating a file via apache:

Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/roundup/cgi/wsgi_handler.py", line 127, in __call__
    client.main()
  File "/usr/local/lib/python2.7/dist-packages/roundup/cgi/client.py", line 514, in main
    self.handle_rest()
  File "/usr/local/lib/python2.7/dist-packages/roundup/cgi/client.py", line 652, in handle_rest
    self.write(output)
  File "/usr/local/lib/python2.7/dist-packages/roundup/cgi/client.py", line 2186, in write
    self.header()
  File "/usr/local/lib/python2.7/dist-packages/roundup/cgi/client.py", line 2532, in header
    self._socket_op(self.request.start_response, headers, response)
  File "/usr/local/lib/python2.7/dist-packages/roundup/cgi/client.py", line 2050, in _socket_op
    call(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/roundup/cgi/wsgi_handler.py", line 72, in start_response
    message), headers)
TypeError: expected byte string object, value of type NoneType found

Note that I've instrumented the code, the real line where this occurs in wsgi_handler.py is 68.

It *looks* like this is not in start_response but in the _start_response method called which seems to be a method of the mod_wsgi.Adapter object which is probably written in C.
When I'm logging what is passed to the _start_response method, several headers have None as a value.

When I'm logging response_code, message, headers:

201 Created [('Content-Length', '107'), ('Access-Control-Allow-Headers', 'Content-Type, Authorization, X-Requested-With, X-HTTP-Method-Override'), ('Content-Encoding', 'gzip'), ('Vary', 'Accept-Encoding'), ('Location', 'http://bee.priv.zoo:7070/qso/rest/data/file/2898'), ('Allow', None), ('Access-Control-Allow-Origin', '*'), ('Access-Control-Allow-Methods', None), ('Content-Type', 'application/json')]

So the 'Allow' and the 'Access-Control-Allow-Methods' headers have None as a value.

Any Idea why this happens? The behaviour is quite new but I've not yet pinpointed since when this occurs.