在 GraphQL 中过滤嵌入式文档列表

Question

我正在使用 MongoDB 后端（通过 MongoEngine）在 Python/Graphene 中构建 GraphQL 应用程序。一切都运行良好，但注意到没有很多文档用于处理嵌入文档的嵌套列表。我认为 GraphQL 的一个强大功能是能够仅投影您想要的属性，但似乎并非完全如此。

以这个集合为例：

[
  {
    "name": "John Doe",
    "age": 37,
    "preferences": [
      {
        "key": "colour",
        "value": "Green"
      },
      {
        "key": "smell",
        "value": "onions cooking in butter"
      },
      ...
    ]
  },
  ...
]

如果我想通过 GraphQL 查找特定对象，我会通过类似的查询进行查找

{
    person(name: "John Doe"){edges{node{
      name age preferences{edges{node{
        key value
      }}}
    }}}
}

但这可能会带回数百个嵌套文档。我想做的是将请求的嵌套文档标识为投影请求的一部分。

{
    person(name: "John Doe"){edges{node{
      name age preferences(key: "colour"){edges{node{
        key value
      }}}
    }}}
}

我阅读 GraphQL 规范的理解是这些子查询是不可能的，但想先与专家确认。如果可能的话，我将如何实现它来支持这些类型的请求？

更新也许架构示例会提供一些更有见地的响应。

class PreferenceModel(mongoengine.EmbeddedDocument):
    key = mongoengine.fields.StringField()
    value = mongoengine.fields.StringField()


class Preference(graphene_mongo.MongoengineObjectType):
    class Meta:
        interfaces = (graphene.relay.Node, )
        model = PreferenceModel


class PersonModel(mongoengine.Document):
    meta = {'collection': 'persons'}
    name = mongoengine.fields.StringField()
    age = mongoengine.fields.IntField()
    preferences = mongoengine.fields.EmbeddedDocumentListField(PreferenceModel)


class Person(graphene_mongo.MongoengineObjectType):
    class Meta:
        interfaces = (graphene.relay.Node, )
        model = PersonModel


class Query(graphene.ObjectType):
    person = graphene_mongo.MongoengineConnectionField(Person)

schema = graphene.Schema(query=Query, types=[Person])
app = starlette.graphql.GraphQLApp(schema=schema)

使用上述结构，需要进行哪些更改才能允许对嵌套对象进行查询/过滤？

Answer 1

我有一个类似的问题，但正在使用 graphene-django。我使用 DjangoObjectType 上的自定义解析器解决了它，如下所示：

import graphene
from graphene_django import DjangoObjectType
from .models import Question, Choice, SubChoice


class SubChoiceType(DjangoObjectType):
    class Meta:
        model = SubChoice
        fields = "__all__"


class ChoiceType(DjangoObjectType):
    sub_choices = graphene.List(SubChoiceType, search_sub_choices=graphene.String())

    class Meta:
        model = Choice
        fields = ("id", "choice_text", "question")

    def resolve_sub_choices(self, info, search_sub_choices=None):
        if search_sub_choices:
            return self.subchoice_set.filter(sub_choice_text__icontains=search_sub_choices)

        return self.subchoice_set.all()


class QuestionType(DjangoObjectType):
    choices = graphene.List(ChoiceType, search_choices=graphene.String())

    class Meta:
        model = Question
        fields = ("id", "question_text")

    def resolve_choices(self, info, search_choices=None):
        if search_choices:
            return self.choice_set.filter(choice_text__icontains=search_choices)

        return self.choice_set.all()


class Query(graphene.ObjectType):
    all_questions = graphene.List(QuestionType, search_text=graphene.String())
    all_choices = graphene.List(ChoiceType, search_text=graphene.String())
    all_sub_choices = graphene.List(SubChoiceType)

    def resolve_all_questions(self, info, search_text=None):
        qs = Question.objects.all()
        if search_text:
            qs = qs.filter(question_text__icontains=search_text)

        return qs

    def resolve_all_choices(self, info, search_text=None):
        qs = Choice.objects.all()
        if search_text:
            qs = qs.filter(choice_text__icontains=search_text)

        return qs

    def resolve_all_sub_choices(self, info):
        qs = SubChoice.objects.all()
        return qs


schema = graphene.Schema(query=Query)

您可以在此处找到示例：https://github.com/allangz/graphene_subfilters/blob/main/mock_site/polls/schema.py

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