応答形式を変更するとDjango-Pistonがtext/plainとしてJSON/Dictionaryを返す

Question

django-pistonを使用しているPython辞書オブジェクトをJSON経由で呼び出し元に返す別のプログラマーが作成したコードをデバッグします。私はピストンhereの文書に従っています。

私は手動でresponse = rc.CREATEDとresponse.content = my_dictを設定した場合、レスポンスのコンテンツタイプが、私はresponse['Content-Type'] = 'application/json; charset=utf-8'でそれを上書きしようとした場合でも、常にtext/plainであるいくつかの奇妙な行動に気づきました。

ここにいくつかのサンプルコードがあります。

class RequestHandler(BaseHandler): 
    '''API handler for translation request queries.''' 

    # we don't allow updating translation requests 
    allowed_methods = ('GET', 'POST', 'DELETE') 

    @throttle(MAX_REQUESTS_PER_MINUTE, 60) 
    def read(self, request, shortname = None, results = False): 
     '''Handles a GET request asking about translation requests.''' 
     not_deleted = TranslationRequest.objects.exclude(deleted = True) 
     not_deleted = not_deleted.filter(owner = request.user) 
     if shortname is None: 
      objects = not_deleted.all() 
     else: 
      try: 
       _request_uuid = uuid.UUID(shortname) 
       objects = [get_object_or_404(not_deleted, request_id=shortname)] 
      except ValueError: 
       objects = [get_object_or_404(not_deleted, shortname=shortname)] 
     objects = [ RequestHandler.request_to_dict(o, results) 
        for o in objects ] 
     if len(objects) == 1: 
      objects = objects[0] 
     return objects 

    @throttle(MAX_REQUESTS_PER_MINUTE, 60) 
    def create(self, request, shortname = None, results = False): 
     '''Handles a POST request to create a new translation request.''' 
     if shortname is not None or results: 
      return rc.BAD_REQUEST 
     print 'CREATE content-type', request.content_type # DEBUG 
     # get the data from the POST request 
     postdata = self.flatten_dict(request.POST) 
     # ensure that the worker field is present 
     postdata['worker'] = postdata.get('worker','') 
     # validate POST data using our Django form 
     form = TranslationRequestForm(request.user, postdata, request.FILES) 
     try: 
      if not form.is_valid(): 
       return rc.BAD_REQUEST 
     except KeyError: 
      return rc.BAD_REQUEST 
     # create a new request object 
     new = TranslationRequest() 
     new.shortname = form.cleaned_data['shortname'] 
     new.owner = request.user 
     new.worker = form.cleaned_data['worker'] 
     # create a new worker message 
     message = TranslationRequestMessage() 
     message.request_id = new.request_id 
     message.source_language = form.cleaned_data['source_language'] 
     message.target_language = form.cleaned_data['target_language'] 
     message.source_text = u'' 
     for chunk in request.FILES['source_text'].chunks(): 
      message.source_text += unicode(chunk, 'utf-8') 

     handle = open('{0}/{1}.message'.format(TRANSLATION_MESSAGE_PATH, 
               new.request_id), 'w+b') 
     handle.write(message.SerializeToString()) 
     handle.close() 

     new.save() 
     new.start_translation() 

     messages.add_message(request, messages.SUCCESS, 'Successfully ' \ 
          'started translation request "{0}".'.format(
           new.shortname)) 

     # return 201 CREATED 
     response = rc.CREATED 
     # put the URI of the newly created object into the HTTP header 
     # Location field (see RFC 2616) 
     response['Content-Type'] = 'application/json; charset=utf-8' 
     response['Location'] = reverse('requests', args=[new.request_id + '/']) 
     # echo the created object inside the HTTP response 
     # NOTE: this overwrites the "Location" header field set above. 
     # See piston.resource.__call__() 
     response.content = RequestHandler.request_to_dict(new, include_results=False) 
     return response 

    @staticmethod 
    def request_to_dict (request, include_results = False): 
     '''Transforms a TranslationRequest object to a Python 
     dictionary.''' 
     retval = {} 
     retval['owner'] = request.owner.username 
     retval['shortname'] = request.shortname 
     retval['worker'] = request.worker.shortname 
     retval['created'] = request.created 
     retval['request_id'] = request.request_id 
     retval['ready'] = request.is_ready() 
     if include_results: 
      translation_message = request.fetch_translation() 
      if type(translation_message) == TranslationRequestMessage: 
       retval['source_language'] = translation_message.source_language 
       retval['target_language'] = translation_message.target_language 
       retval['result'] = translation_message.target_text 
       retval.update([(x.key, x.value) for x in 
           translation_message.packet_data]) 
      else: 
       retval['result'] = translation_message 
     return retval 

Wiresharkを使用すると、read（）はJSONを正しく返します。しかし

GET /mt-serverland/dashboard/api/results/?token=7594f0db HTTP/1.1 

Host: localhost:8081 

Accept-Encoding: identity 



HTTP/1.0 200 OK 

Date: Sat, 01 Jan 2011 01:05:36 GMT 

Server: WSGIServer/0.1 Python/2.6.6 

Vary: Authorization 

Content-Type: application/json; charset=utf-8 



[ 
    { 
    "created": "2010-12-31 17:47:51", 
    "source_language": "eng", 
    "worker": "GoogleWorker", 
    "owner": "admin", 
    "result": "Esta es una prueba.\nEspero que este archivo se traducirá correctamente.", 
    "request_id": "b4ca75a301714a5097ce4daab35d370b", 
    "ready": true, 
    "shortname": "test01", 
    "target_language": "spa" 
    } 
] 

、私は（）を作成使用しようと、私は次の応答を得る：私はちょうどRequestHandler.request_to_dict()によって返されたオブジェクトを返すために）（作成、変更した場合

HTTP/1.0 201 CREATED 

Date: Thu, 30 Dec 2010 18:40:25 GMT 

Server: WSGIServer/0.1 Python/2.6.6 

Vary: Authorization, Cookie 

Content-Type: text/plain 

Location: http://localhost:8081/mt-serverland/dashboard/api/requests/6614acd8491e4034bcb9b6a9430e6947/ 

Set-Cookie: sessionid=5536e58e88ded4365b536a354d3b8a7d; expires=Thu, 13-Jan-2011 18:40:25 GMT; Max-Age=1209600; Path=/ 



{'created': datetime.datetime(2010, 12, 30, 19, 40, 25, 282665), 'worker': u'GoogleWorker', 'ready': False, 'request_id': '6614acd8491e4034bcb9b6a9430e6947', 'owner': u'admin', 'shortname': u'1234567'}

を、そしてレスポンスの内容application/jsonです。これがなぜ起こっているのでしょうか？ありがとう！

Answer 1

非常に似た問題が発生しました。ピストンとDjangoソースを掘り後、私はこれをしようとすることを決めた、それが働いた：HTTPでこれを生み出す

resp = rc.CREATED 
resp.content = dict(
    attendee_id=attendee.id, 
    order_id=order.id, 
) 
return resp 

（簡潔にするため削除いくつかのヘッダーを）。

< HTTP/1.1 201 CREATED 
< Date: Thu, 27 Jan 2011 16:59:38 GMT 
< Server: WSGIServer/0.1 Python/2.6.5 
< Vary: Authorization 
< Content-Type: application/json; charset=utf-8 
< Transfer-Encoding: chunked 
< 
{ 
    "order_id": 22446505, 
    "attendee_id": 18 
}