cgi.FieldStorage remains empty
===

i am trying to set up a possibility to upload xml files using mod_wsgi. to do so i build a formular like this one:

     <form action="upload.py" method="post" enctype="multipart/form-data">
          <input name="file" type="file" accept="text/xml"><br/>
          <input type="submit" value="upload">
     </form>

and a file `upload.py`:

     ..
     form = cgi.FieldStorage(fp=environ['wsgi.input'], 
                             environ=environ, 
                             keep_blank_values=True)
     fileitem = form['file']
     ..

however, this gives me a keyerror while accessing 'file' in form. printing `environ['wsgi.input'].read(request_body_size)` shows:

    ------WebKitFormBoundaryeplWkFZe2clFMtgf
    Content-Disposition: form-data; name="file"; filename="file.xml"
    Content-Type: application/octet-stream
    
    <?xml version="1.0" ?>
    ....

as consequence, wsgi.input seems to be valid. debugging exposes that `cgi.FieldStorage() = FieldStorage(None, None, [])`. have you an idea where the problem may be? am i missing something?

