我正在用Tastypie构建API，并且在保存多对多字段时遇到了问题。
我有一个模型调用Pest，另一个名为Call，并且Call有一个名为pests的字段，它表示可以应用于调用的有害生物。这些已经存在，并且用户可以选择一个或多个应用于该呼叫-无意与Call对象同时创建它们。
默认情况下，当我尝试通过POST创建新呼叫时收到以下错误：
{"error_message": "Cannot resolve keyword 'url' into field. Choices are: baitpoint, call, description, id, name, operator", "traceback": "Traceback (most recent call last):\n\n File \"/home/matthew/Projects/Pestability/venv/local/lib/python2.7/site-packages/tastypie/resources.py\", line 217, in wrapper\n response = callback(request, *args, **kwargs)\n\n File \"/home/matthew/Projects/Pestability/venv/local/lib/python2.7/site-packages/tastypie/resources.py\", line 459, in dispatch_list\n return self.dispatch('list', request, **kwargs)\n\n File \"/home/matthew/Projects/Pestability/venv/local/lib/python2.7/site-packages/tastypie/resources.py\", line 491, in dispatch\n response = method(request, **kwargs)\n\n File \"/home/matthew/Projects/Pestability/venv/local/lib/python2.7/site-packages/tastypie/resources.py\", line 1357, in post_list\n updated_bundle = self.obj_create(bundle, **self.remove_api_resource_names(kwargs))\n\n File \"/home/matthew/Projects/Pestability/venv/local/lib/python2.7/site-packages/tastypie/resources.py\", line 2150, in obj_create\n return self.save(bundle)\n\n File \"/home/matthew/Projects/Pestability/venv/local/lib/python2.7/site-packages/tastypie/resources.py\", line 2300, in save\n m2m_bundle = self.hydrate_m2m(bundle)\n\n File \"/home/matthew/Projects/Pestability/venv/local/lib/python2.7/site-packages/tastypie/resources.py\", line 964, in hydrate_m2m\n bundle.data[field_name] = field_object.hydrate_m2m(bundle)\n\n File \"/home/matthew/Projects/Pestability/venv/local/lib/python2.7/site-packages/tastypie/fields.py\", line 853, in hydrate_m2m\n m2m_hydrated.append(self.build_related_resource(value, **kwargs))\n\n File \"/home/matthew/Projects/Pestability/venv/local/lib/python2.7/site-packages/tastypie/fields.py\", line 653, in build_related_resource\n return self.resource_from_uri(self.fk_resource, value, **kwargs)\n\n File \"/home/matthew/Projects/Pestability/venv/local/lib/python2.7/site-packages/tastypie/fields.py\", line 573, in resource_from_uri\n obj = fk_resource.get_via_uri(uri, request=request)\n\n File \"/home/matthew/Projects/Pestability/venv/local/lib/python2.7/site-packages/tastypie/resources.py\", line 838, in get_via_uri\n return self.obj_get(bundle=bundle, **self.remove_api_resource_names(kwargs))\n\n File \"/home/matthew/Projects/Pestability/venv/local/lib/python2.7/site-packages/tastypie/resources.py\", line 2125, in obj_get\n object_list = self.get_object_list(bundle.request).filter(**kwargs)\n\n File \"/home/matthew/Projects/Pestability/venv/local/lib/python2.7/site-packages/django/db/models/query.py\", line 655, in filter\n return self._filter_or_exclude(False, *args, **kwargs)\n\n File \"/home/matthew/Projects/Pestability/venv/local/lib/python2.7/site-packages/django/db/models/query.py\", line 673, in _filter_or_exclude\n clone.query.add_q(Q(*args, **kwargs))\n\n File \"/home/matthew/Projects/Pestability/venv/local/lib/python2.7/site-packages/django/db/models/sql/query.py\", line 1266, in add_q\n can_reuse=used_aliases, force_having=force_having)\n\n File \"/home/matthew/Projects/Pestability/venv/local/lib/python2.7/site-packages/django/db/models/sql/query.py\", line 1134, in add_filter\n process_extras=process_extras)\n\n File \"/home/matthew/Projects/Pestability/venv/local/lib/python2.7/site-packages/django/db/models/sql/query.py\", line 1332, in setup_joins\n \"Choices are: %s\" % (name, \", \".join(names)))\n\nFieldError: Cannot resolve keyword 'url' into field. Choices are: baitpoint, call, description, id, name, operator\n"}
所以我看了一下，发现this answer，似乎涵盖了类似的情况。我将hydrate_pests方法添加到CallResource类中，如下所示：
class AbstractModelResource(ModelResource):
class Meta:
authorization = DjangoAuthorization()
authentication = ApiKeyAuthentication()
cache = SimpleCache(timeout=10)
always_return_data = True
class FilteredByOperatorAbstractModelResource(AbstractModelResource):
def authorized_read_list(self, object_list, bundle):
user = bundle.request.user
site_user = SiteUser.objects.get(user=user)
return object_list.filter(operator=site_user.operator)
class PestResource(FilteredByOperatorAbstractModelResource):
class Meta(AbstractModelResource.Meta):
queryset = Pest.objects.all()
resource_name = 'pest'
allowed_methods = ['get']
class CallResource(AbstractModelResource):
client = fields.ForeignKey(ClientResource, 'client')
operator = fields.ForeignKey(OperatorResource, 'operator')
pests = fields.ManyToManyField(PestResource, 'pests', null=True)
class Meta(AbstractModelResource.Meta):
queryset = Call.objects.all()
resource_name = 'call'
def hydrate_pests(self, bundle):
pests = bundle.data.get('pests', [])
pest_ids = []
for pest in pests:
m = re.search('\/api\/v1\/pests\/(\d+)\/', str(pest))
try:
id = m.group(1)
pest_ids.append(id)
except AttributeError:
pass
bundle.data['pests'] = Pest.objects.filter(id__in=pest_ids)
return bundle
pests字段如下传递：
0: "/api/v1/pests/6/"
1: "/api/v1/pests/7/"
并且当我运行bundle.data.get('pests', [])时，有害生物URL正确显示-如果我使用PDB设置跟踪，则可以验证URL是否通过，并且Pest.objects.filter(id__in=pest_ids)返回正确的项目。但是，尽管HTTP POST请求成功，但是没有更新pests字段以反映新数据。
有人可以看到我哪里出问题了吗？我是否正确地将Pest对象的列表传递给bundle.data ['pests']，或者这不是我应该如何将这些数据传递给该字段的方法？
实际传递给bundle.data的内容如下：
{'pests': [<Pest: Rats>, <Pest: Mice>], 'notes': u'Blah', 'first_choice_visit_time': u'2013-07-18T02:02', 'client': u'/api/v1/client/28/', 'date': u'2013-07-18', 'second_choice_visit_time': u'2014-03-03T03:02'}