在django- tastype中，向one_to_many关系中添加一个项只会在第二次生效

Question

给定这些模型:

class ModelA(models.Model):
    # Some fields
    # Some relationship
class ModelB(models.Model):
    # Some fields
    a = models.ForeignKey(ModelA)

和这些品味类型的资源:

class ResourceA(ModelResource):
    b_list = fields.ToManyField('app.api.ResourceB', 'a_set', null=True, related_name='a')
class ResourceB(ModelResource):
    a = fields.ToOneField(ResourceA, 'a', null=True)

如果我访问ResourceB的详细端点(/api/v1/resourceA/##/)，我可以看到所有相关的B的uri -反向关系工作。返回的数据如下所示:

{
    'b_list': [
        '/api/v1/resourceB/1/',
        '/api/v1/resourceB/2/',
    ]
}

如果我试图PUT或PATCH一个资源a来添加一个新的B，用这个数据说:

{
    'b_list': [
        '/api/v1/resourceB/1/',
        '/api/v1/resourceB/2/',
        '/api/v1/resourceB/3/',
    ]
}

我得到错误:'ManyRelatedManager' object has no attribute 'add'与这个stacktrace:

Traceback (most recent call last):
  File "/home/username/.virtualenvs/myapp/local/lib/python2.7/site-packages/tastypie/resources.py", line 202, in wrapper
    response = callback(request, *args, **kwargs)
  File "/home/username/.virtualenvs/myapp/local/lib/python2.7/site-packages/tastypie/resources.py", line 449, in dispatch_detail
    return self.dispatch('detail', request, **kwargs)
  File "/home/username/.virtualenvs/myapp/local/lib/python2.7/site-packages/tastypie/resources.py", line 472, in dispatch
    response = method(request, **kwargs)
  File "/home/username/.virtualenvs/myapp/local/lib/python2.7/site-packages/tastypie/resources.py", line 1611, in patch_detail
    self.update_in_place(request, bundle, deserialized)
  File "/home/username/.virtualenvs/myapp/local/lib/python2.7/site-packages/tastypie/resources.py", line 1634, in update_in_place
    return self.obj_update(bundle=original_bundle, **kwargs)
  File "/home/username/.virtualenvs/myapp/local/lib/python2.7/site-packages/tastypie/resources.py", line 2166, in obj_update
    return self.save(bundle, skip_errors=skip_errors)
  File "/home/username/.virtualenvs/myapp/local/lib/python2.7/site-packages/tastypie/resources.py", line 2257, in save
    self.save_m2m(m2m_bundle)
  File "/home/username/.virtualenvs/myapp/local/lib/python2.7/site-packages/tastypie/resources.py", line 2382, in save_m2m
    related_resource.save(updated_related_bundle)
  File "/home/username/.virtualenvs/myapp/local/lib/python2.7/site-packages/tastypie/resources.py", line 2257, in save
    self.save_m2m(m2m_bundle)
  File "/home/username/.virtualenvs/myapp/local/lib/python2.7/site-packages/tastypie/resources.py", line 2382, in save_m2m
    related_resource.save(updated_related_bundle)
  File "/home/username/.virtualenvs/myapp/local/lib/python2.7/site-packages/tastypie/resources.py", line 2257, in save
    self.save_m2m(m2m_bundle)
  File "/home/username/.virtualenvs/myapp/local/lib/python2.7/site-packages/tastypie/resources.py", line 2385, in save_m2m
    related_mngr.add(*related_objs)
AttributeError: 'ManyRelatedManager' object has no attribute 'add'

如果我随后立即 PUT/PATCH相同的数据，我没有得到错误，没有堆栈跟踪，并且项目成功添加到关系中。我不明白为什么会这样。

此外，我似乎只能向关系中添加项目-如果能够删除它们就太好了。

Answer 1

好的。这是一个Django错误。我不确定，尝试在django模型中使用related_name。

class ModelB(models.Model):
# Some fields
a = models.ForeignKey(ModelA, related_name='b_list')

从资源中删除related_name，属性名必须从'a_set'更改为'b_list'

class ResourceA(ModelResource):
b_list = fields.ToManyField('app.api.ResourceB', 'b_list', null=True)