具有循环依赖的 GraphQL 设计

Question

在我的结构中，我想引入如下所示的循环依赖关系，以避免向后端提交两个单独的查询。有人可以建议如何在 Python 中完成此操作吗？

下面是示例代码：

父级.py

import graphene

class Parent(graphene.ObjectType):
    id = graphene.ID()
    name = graphene.String()
    child= graphene.Field(Child)

孩子.py

import graphene

class Child(graphene.ObjectType):
    id = graphene.ID()
    name = graphene.String()
    parent = graphene.Field(Parent)

测试.py

from parent import Parent

print("TEST")

错误

ImportError: cannot import name 'Parent' from partially initialized module 'parent' (most likely due to a circular import) 

更新 以下内容也不起作用（循环导入错误）

import graphene

class Child(graphene.ObjectType):
    import app.parent as P
    id = graphene.ID()
    name = graphene.String()
    parent = graphene.Field(P.Parent)

...
import graphene

class Parent(graphene.ObjectType):
    import app.child as C
    id = graphene.ID()
    name = graphene.String()
    child = graphene.Field(C.Child)
...

from app.parent import Parent

print("TEST")

AttributeError: partially initialized module 'app.parent' has no attribute 'Parent' (most likely due to a circular import)

Answer 1

总而言之- graphene.Field('<class-loc>.<class-name>')。在你的情况下，graphene.Field('parent.Parent')应该graphene.Field('child.Child')完成这项工作。

遇到了完全相同的问题，并且认为必须有某种方法可以仅使用字符串表示来定义模式。在浏览代码时，我发现import_string内部使用的函数帮助我理解了如何做到这一点 -

https://github.com/graphql-python/graphene/blob/a53b782bf8ec5612d5cceb582fbde68eeba859aa/graphene/utils/module_loading.py#L5