如何通过OneToOne字段在URL中使用用户名替代PK

我希望API接口通过用户名（username）而非主键（PK）访问用户信息，尝试配置lookup_field但未生效，相关代码如下：

models.py #

class IndividualUser(models.Model):
    individual_user = models.OneToOneField(User, on_delete=models.CASCADE, primary_key=True)
    first_name = models.CharField(_("first name"), max_length=150)
    last_name = models.CharField(_("last name"), max_length=150)

urls.py #

path('api/profile/<str:individual_user>/', IndividualClientDetailApiView.as_view()),

views.py #

class IndividualClientDetailApiView(generics.RetrieveAPIView):
    queryset = IndividualUser.objects.all()
    serializer_class = IndividualClientSerializer
    permission_classes = (IsAuthenticated, IsOwnerOrAdminOrReadOnly)

    lookup_field = 'individual_user'

问题根源在于你设置的lookup_field = 'individual_user'指向的是关联的User对象实例，而URL中传递的是用户名字符串，两者类型不匹配，导致无法正确执行查询。

你可以通过以下两种方式解决：

方式一：修改lookup_field并同步URL参数名 #

1. 更新视图类的lookup_field，使用双下划线跨关联模型查询User的username字段：

class IndividualClientDetailApiView(generics.RetrieveAPIView):
    queryset = IndividualUser.objects.all()
    serializer_class = IndividualClientSerializer
    permission_classes = (IsAuthenticated, IsOwnerOrAdminOrReadOnly)

    lookup_field = 'individual_user__username'

2. 修改URL路径中的参数名，使其语义更清晰：

path('api/profile/<str:username>/', IndividualClientDetailApiView.as_view()),

方式二：保留原有URL参数名，添加lookup_url_kwarg #

如果不想修改URL中的参数名，只需在视图类中额外配置lookup_url_kwarg，指定URL参数对应到查询字段：

class IndividualClientDetailApiView(generics.RetrieveAPIView):
    queryset = IndividualUser.objects.all()
    serializer_class = IndividualClientSerializer
    permission_classes = (IsAuthenticated, IsOwnerOrAdminOrReadOnly)

    lookup_field = 'individual_user__username'
    lookup_url_kwarg = 'individual_user'

调整后，Django就能根据URL传入的用户名，通过IndividualUser关联的User模型的username字段正确匹配到目标用户记录。

内容的提问来源于stack exchange，提问作者Zesshi