如果运行以下代码,我会超出最大递归深度:
from tastypie import fields, utils
from tastypie.resources import ModelResource
from core.models import Project, Client
class ClientResource(ModelResource):
projects = fields.ToManyField(
'api.resources.ProjectResource', 'project_set', full=True
)
class Meta:
queryset = Client.objects.all()
resource_name = 'client'
class ProjectResource(ModelResource):
client = fields.ForeignKey(ClientResource, 'client', full=True)
class Meta:
queryset = Project.objects.all()
resource_name = 'project'
# curl http://localhost:8000/api/client/?format=json
# or
# curl http://localhost:8000/api/project/?format=json
如果其中一个关系有效,则设置为full = False。我确实理解为什么会发生这种情况,但我需要两种关系才能带来数据,而不仅仅是“resource_uri”。是否有Tastypie方法来做到这一点?我设法解决了在我的项目模型上创建序列化方法的问题,但它远非优雅。感谢。
答案 0 :(得分:13)
您必须至少在一个资源上覆盖full_dehydrate
方法,以跳过导致递归的脱水相关资源。
或者,您可以定义两种类型的资源,这些资源使用与full=True
相同的模型,另一种使用full=False
。
答案 1 :(得分:3)
感谢@astevanovic指出正确的方向。
我发现重写dehydrate
方法只处理某些指定的字段比覆盖full_hydrate
方法跳过字段要简单一些。
为了追求可重用性,我想出了以下代码片段。希望它对某些人有用:
class BeeModelResource(ModelResource):
def dehydrate(self, bundle):
bundle = super(BeeModelResource, self).dehydrate(bundle)
bundle = self.dehydrate_partial(bundle)
return bundle
def dehydrate_partial(self, bundle):
for field_name, resource_field in self.fields.items():
if not isinstance(resource_field, RelatedField):
continue
if resource_field.full: # already dehydrated
continue
if not field_name in self._meta.partial_fields:
continue
if isinstance(resource_field, ToOneField):
fk_object = getattr(bundle.obj, resource_field.attribute)
fk_bundle = Bundle(obj=fk_object, request=bundle.request)
fk_resource = resource_field.get_related_resource(fk_object)
bundle.data[field_name] = fk_resource.dehydrate_selected(
fk_bundle, self._meta.partial_fields[field_name]).data
elif isinstance(resource_field, ToManyField):
data = []
fk_objects = getattr(bundle.obj, resource_field.attribute)
for fk_object in fk_objects.all():
fk_bundle = Bundle(obj=fk_object, request=bundle.request)
fk_resource = resource_field.get_related_resource(fk_object)
fk_bundle = fk_resource.dehydrate_selected_fields(
fk_bundle, self._meta.partial_fields[field_name])
data.append(fk_bundle.data)
bundle.data[field_name] = data
return bundle
def dehydrate_selected_fields(self, bundle, selected_field_names):
# Dehydrate each field.
for field_name, field_object in self.fields.items():
# A touch leaky but it makes URI resolution work.
# (borrowed from tastypie.resources.full_dehydrate)
if field_name in selected_field_names and not self.is_special_fields(field_name):
if getattr(field_object, 'dehydrated_type', None) == 'related':
field_object.api_name = self._meta.api_name
field_object.resource_name = self._meta.resource_name
bundle.data[field_name] = field_object.dehydrate(bundle)
bundle.data['resource_uri'] = self.get_resource_uri(bundle.obj)
bundle.data['id'] = bundle.obj.pk
return bundle
@staticmethod
def is_special_fields(field_name):
return field_name in ['resource_uri']
以@sigmus为例,资源需要进行3次修改:
BeeModuleResource
作为其超类(或者,将dehydrate_partial
添加到一个资源,将dehydrate_selected
添加到另一个资源。)full=True
partial_fields
添加到资源Meta
未设置资源```
class ClientResource(BeeModelResource): # make BeeModelResource a super class
projects = fields.ToManyField(
'api.resources.ProjectResource', 'project_set'
) # remove full=True
class Meta:
queryset = Client.objects.all()
resource_name = 'client'
partial_fields = {'projects': ['memo', 'title']} # add partial_fields
class ProjectResource(BeeModelResource): # make BeeModelResource a super class
client = fields.ForeignKey(ClientResource, 'client', full=True)
class Meta:
queryset = Project.objects.all()
resource_name = 'project'
答案 2 :(得分:3)
死亡简单解决方案:在两个关系字段上设置use_in = 'list'
kwarg!
文档:http://django-tastypie.readthedocs.org/en/latest/fields.html#use-in