问如何使用Graphene GraphQL解析嵌套在另一种类型中的字段？
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Stack Overflow用户

提问于 2019-08-07 02:21:43

回答 1查看 6.7K关注 0票数 11

我有3个文件：authors.py、posts.py和schema.py。

Posts只有一个作者，查询构建在架构文件中。

我试图从Author内部解析Post，而没有在Post中声明一个解析器函数，因为Author已经为自己声明了一个解析器函数。下面的代码可以工作，但我必须从resolve_author类型内部引用Post，这似乎不正确。我认为Graphene应该将parent param直接传递给Author，不是吗？

如果我没有在author类型中为Post设置一个解析器，它只返回null。

schema.py

import graphene
from graphql_api import posts, authors


class Query(posts.Query, authors.Query):
    pass


schema = graphene.Schema(query=Query)

authors.py

from graphene import ObjectType, String, Field


class Author(ObjectType):
    id = ID()
    name = String()


class Query(ObjectType):
    author = Field(Author)

    def resolve_author(parent, info):
        return {
            'id': '123',
            'name': 'Grizzly Bear',
            'avatar': '#984321'
        }

posts.py

from graphene import ObjectType, String, Field
from graphql_api import authors


class Post(ObjectType):
    content = String()
    author = Field(authors.Author)

    def resolve_author(parent, info):
        # I'm doing like this and it works, but it seems wrong. 
        # I think Graphene should be able to use my resolver 
        # from the Author automatically...
        return authors.Query.resolve_author(parent,
                                            info, id=parent['authorId'])


class Query(ObjectType):
    post = Field(Post)

    def resolve_post(parent, info):
        return {
            'content': 'A title',
            'authorId': '123',
        }

python

graphql

graphene-python

回答 1

Stack Overflow用户

发布于 2019-08-07 04:58:45

Query.resolve_author不会被调用，因为它与Post对象之间没有任何关系。

我建议如下：

from graphene import ObjectType, String, Field
from graphql_api import authors


class Post(ObjectType):
    content = String()
    author = Field(authors.Author)

    def resolve_author(self, info):
        # author_utils.get_author returns complete object that will be passed into Author's object resolvers (if some fields are missing)
        # I suggest returning here an object from database so author resolver would extract another fields inside
        # But it may be just an id that will be passed in Author resolvers as first arguments
        return author_utils.get_author(post_id=self.id)


class Query(ObjectType):
    post = Field(Post)

    def resolve_post(parent, info):
        # Here you shouldn't author_id as it's not defined in type 
        return {
            'content': 'A title',
        }

和Author (假设author_utils.get_author只返回一个id)：

class Author(ObjectType):
    id = ID()
    name = String()

    def resolve_id(id, info):
        # root here is what resolve_author returned in post. Be careful, it also will be called if id is missing after Query.resolve_author
        return id

    def resolve_name(id, info):
        # same as resolve_id
        return utils.get_name_by_id(id)