import urllib3
pool = urllib3.connection_from_url('http://127.0.0.1:8090')
resp = pool.request('POST', '/polls/', fields={'key1':'value1', 'key2':'value2'}, headers={'Content-Type':'application/json'}, encode_multipart=False)

def _load_post_and_files(self):
  """Populate self._post and self._files if the content-type is a form type"""
  if self.method != 'POST':
   self._post, self._files = QueryDict(encoding=self._encoding), MultiValueDict()
   return
  if self._read_started and not hasattr(self, '_body'):
   self._mark_post_parse_error()
   return

  if self.content_type == 'multipart/form-data':
   if hasattr(self, '_body'):
    # Use already read data
    data = BytesIO(self._body)
   else:
    data = self
   try:
    self._post, self._files = self.parse_file_upload(self.META, data)
   except MultiPartParserError:
    # An error occurred while parsing POST data. Since when
    # formatting the error the request handler might access
    # self.POST, set self._post and self._file to prevent
    # attempts to parse POST data again.
    # Mark that an error occurred. This allows self.__repr__ to
    # be explicit about it instead of simply representing an
    # empty POST
    self._mark_post_parse_error()
    raise
  elif self.content_type == 'application/x-www-form-urlencoded':
   self._post, self._files = QueryDict(self.body, encoding=self._encoding), MultiValueDict()
  else:
   self._post, self._files = QueryDict(encoding=self._encoding), MultiValueDict()