从 SQLAlchemy 类属性生成石墨烯突变输入

Question

我目前为我的项目定义了以下突变：

我的班级PlanetAttribute 用于定义石墨烯字段，用作我的突变的输入

class PlanetAttribute:
    name = graphene.String(required=True, description="Name of the planet.")
    rotation_period = graphene.String(default_value="unknown", description="Rotation period of the planet.")
    orbital_period = graphene.String(default_value="unknown", description="Orbital period of the planet.")
    diameter = graphene.String(default_value="unknown", description="Diameter of the planet.")
    climate = graphene.String(default_value="unknown", description="Climate period of the planet.")
    gravity = graphene.String(default_value="unknown", description="Gravity of the planet.")
    terrain = graphene.String(default_value="unknown", description="Terrain of the planet.")
    surface_water = graphene.String(default_value="unknown", description="Surface water of the planet.")
    population = graphene.String(default_value="unknown", description="Population of the planet.")
    url = graphene.String(default_value="unknown", description="URL of the planet in the Star Wars API.")

我的类CreatePlanetInput 用于定义石墨烯输入对象类型。请注意，它从上面定义的PlanetAttribute 类继承其属性。

class CreatePlanetInput(graphene.InputObjectType, PlanetAttribute):
    """Arguments to create a planet."""
    pass

我的CreatePlanet 类是我的石墨烯突变类，它以CreatePlanetInput 类作为参数。

class CreatePlanet(graphene.Mutation):
    """Create a planet."""
    planet = graphene.Field(lambda: Planet, description="Planet created by this mutation.")

    class Arguments:
        input = CreatePlanetInput(required=True)

    def mutate(self, info, input):
        data = utils.input_to_dictionary(input)
        data['created'] = datetime.utcnow()
        data['edited'] = datetime.utcnow()

        planet = ModelPlanet(**data)
        db_session.add(planet)
        db_session.commit()

        return CreatePlanet(planet=planet)

与其在PlanetAttribute 类中手动声明变异输入，我宁愿从我的SQLALchemy 类ModelPlanet 动态生成它们，定义如下：

class ModelPlanet(Base):
    """Planet model."""

    __tablename__ = 'planet'

    id = Column('id', Integer, primary_key=True, doc="Id of the person.")
    name = Column('name', String, doc="Name of the planet.")
    rotation_period = Column('rotation_period', String, doc="Rotation period of the planet.")
    orbital_period = Column('orbital_period', String, doc="Orbital period of the planet.")
    diameter = Column('diameter', String, doc="Diameter of the planet.")
    climate = Column('climate', String, doc="Climate period of the planet.")
    gravity = Column('gravity', String, doc="Gravity of the planet.")
    terrain = Column('terrain', String, doc="Terrain of the planet.")
    surface_water = Column('surface_water', String, doc="Surface water of the planet.")
    population = Column('population', String, doc="Population of the planet.")
    created = Column('created', String, doc="Record created date.")
    edited = Column('edited', String, doc="Record last updated date.")
    url = Column('url', String, doc="URL of the planet in the Star Wars API.")

    peopleList = relationship(ModelPeople, backref='planet')

你会怎么做？

请注意，我也在此处发布了问题：https://github.com/graphql-python/graphene-sqlalchemy/issues/112

Answer 1

我解决了创建这个类的问题：

from graphene.types.utils import yank_fields_from_attrs
from graphene.utils.subclass_with_meta import SubclassWithMeta_Meta
from graphene_sqlalchemy.registry import get_global_registry
from graphene_sqlalchemy.types import construct_fields

class SQLAlchemyInputObjectType(graphene.InputObjectType):
    @classmethod
    def __init_subclass_with_meta__(  # pylint: disable=arguments-differ
        cls, model=None, registry=None, only_fields=(), exclude_fields=(),
        optional_fields=(), **options
    ):
        if not registry:
            registry = get_global_registry()

        sqla_fields = yank_fields_from_attrs(
            construct_fields(model, registry, only_fields, exclude_fields),
            _as=graphene.Field,
        )

        for key, value in sqla_fields.items():
            if key in optional_fields:
                type_ = value.type if isinstance(
                    value.type, SubclassWithMeta_Meta) else value.type.of_type
                value = type_(
                    description=value.description
                )
            setattr(cls, key, value)

        super(SQLAlchemyInputObjectType, cls).__init_subclass_with_meta__(
            **options
        )

你可以使用它：

class CreatePlanetInput(SQLAlchemyInputObjectType):
    class Meta:
        model = ModelPlanet
        exclude_fields = ('id', )

我试图让它的行为与SQLAlchemyObjectType 相似，所以only_fields 和exclude_fields 应该可以按预期工作。

我还添加了一个optional_fields，使其不再是必需的，非常适合更新突变。

它确实可以处理简单的情况，例如标量字段。关系，比如peopleList，需要手动声明。