Créer de la Réponse JSON dans Django avec le Modèle

J'ai quelques question ici. Je suis en train de retourner une réponse JSON fait d'un message et d'une instance du modèle:

   class MachineModel(models.Model):
       name = models.CharField(max_length=64, blank=False)
       description = models.CharField(max_length=64, blank=False)
       manufacturer = models.ForeignKey(Manufacturer)
       added_by = models.ForeignKey(User, related_name='%(app_label)s_%(class)s_added_by')
       creation_date = models.DateTimeField(auto_now_add=True)
       last_modified = models.DateTimeField(auto_now=True)

    machine_model_model = form.save(commit=False)
    r_user = request.user.userprofile
    machine_model_model.manufacturer_id = manuf_id
    machine_model_model.added_by_id = request.user.id
    machine_model_model.save()
    alert_message = " The'%s' model " % machine_model_model.name
    alert_message += ("for '%s' " % machine_model_model.manufacturer)
    alert_message += "was was successfully created!"
    test = simplejson.dumps(list(machine_model_model))
    data = [{'message': alert_message, 'model': test}]
    response = JSONResponse(data, {}, 'application/json')


class JSONResponse(HttpResponse):
"""JSON response class."""
    def __init__(self, obj='', json_opts={}, mimetype="application/json", *args, **kwargs):
        content = simplejson.dumps(obj, **json_opts)
        super(JSONResponse,self).__init__(content, mimetype, *args, **kwargs)

Mais je reçois:

File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/encoder.py", line 178, in default
raise TypeError(repr(o) + " is not JSON serializable")

TypeError: <MachineModel: "Test12"> is not JSON serializable

Pourquoi est-ce? J'ai vu avant:

models = Model.objects.filter(manufacturer_id=m_id)
json = simplejson.dumps(models)

et qui fonctionne... quelle est la différence?!

Merci!

OriginalL'auteur abisson | 2012-09-23