我已经为使用SQLalchemy的数据库中表示的多态实体编写了Graphene模型。
问题很简单：
我想创建一个反映我的Graphene SQLAlchemy模型的接口，而且a）实现Node或b）不与Node冲突，并允许我检索模型的ID，而无需在Node {id上添加... }到查询字符串。
必须从我的基于ORM的接口中排除ID字段或与Node接口冲突的字段，这样做是为了获取ID，然后需要在Node {id上添加...，这很丑陋。
我创建了一个扩展了Graphene.Interface的SQLAlchemyInterface对象。我的许多（但不是全部）模型都使用了此模型，也使用Node作为接口。第一个问题是它包含一个ID字段，并且与Node接口冲突。
我排除了id字段以免干扰Node，但是发现我无法再直接在模型上查询ID，因此不得不在Node {id}上向查询字符串添加...。
然后，我决定使用此SQLAlchemyInterface扩展Node。我不喜欢这种方法，因为我需要为所有不需要实现SQLAlchemyInterface的模型使用另一个（命名）Node接口
function getMorphType($typeOrClass)
{
$morphMap = array_flip(\Illuminate\Database\Eloquent\Relations\Relation::morphMap());
return array_get($morphMap, $typeOrClass, $typeOrClass);
}
接口隐含，模型+查询代码示例：
class SQLAlchemyInterface(Node):
@classmethod
def __init_subclass_with_meta__(
cls,
model=None,
registry=None,
only_fields=(),
exclude_fields=(),
connection_field_factory=default_connection_field_factory,
_meta=None,
**options
):
_meta = SQLAlchemyInterfaceOptions(cls)
_meta.name = f'{cls.__name__}Node'
autoexclude_columns = exclude_autogenerated_sqla_columns(model=model)
exclude_fields += autoexclude_columns
assert is_mapped_class(model), (
"You need to pass a valid SQLAlchemy Model in " '{}.Meta, received "{}".'
).format(cls.__name__, model)
if not registry:
registry = get_global_registry()
assert isinstance(registry, Registry), (
"The attribute registry in {} needs to be an instance of "
'Registry, received "{}".'
).format(cls.__name__, registry)
sqla_fields = yank_fields_from_attrs(
construct_fields(
model=model,
registry=registry,
only_fields=only_fields,
exclude_fields=exclude_fields,
connection_field_factory=connection_field_factory
),
_as=Field
)
if not _meta:
_meta = SQLAlchemyInterfaceOptions(cls)
_meta.model = model
_meta.registry = registry
connection = Connection.create_type(
"{}Connection".format(cls.__name__), node=cls)
assert issubclass(connection, Connection), (
"The connection must be a Connection. Received {}"
).format(connection.__name__)
_meta.connection = connection
if _meta.fields:
_meta.fields.update(sqla_fields)
else:
_meta.fields = sqla_fields
super(SQLAlchemyInterface, cls).__init_subclass_with_meta__(_meta=_meta, **options)
@classmethod
def Field(cls, *args, **kwargs): # noqa: N802
return NodeField(cls, *args, **kwargs)
@classmethod
def node_resolver(cls, only_type, root, info, id):
return cls.get_node_from_global_id(info, id, only_type=only_type)
@classmethod
def get_node_from_global_id(cls, info, global_id, only_type=None):
try:
node: DeclarativeMeta = one_or_none(session=info.context.get('session'), model=cls._meta.model, id=global_id)
return node
except Exception:
return None
@staticmethod
def from_global_id(global_id):
return global_id
@staticmethod
def to_global_id(type, id):
return id
模式：
class CustomNode(Node):
class Meta:
name = 'UuidNode'
@staticmethod
def to_global_id(type, id):
return '{}:{}'.format(type, id)
@staticmethod
def get_node_from_global_id(info, global_id, only_type=None):
type, id = global_id.split(':')
if only_type:
# We assure that the node type that we want to retrieve
# is the same that was indicated in the field type
assert type == only_type._meta.name, 'Received not compatible node.'
if type == 'User':
return one_or_none(session=info.context.get('session'), model=User, id=global_id)
elif type == 'Well':
return one_or_none(session=info.context.get('session'), model=Well, id=global_id)
class ControlledVocabulary(SQLAlchemyInterface):
class Meta:
name = 'ControlledVocabularyNode'
model = BaseControlledVocabulary
class TrackedEntity(SQLAlchemyInterface):
class Meta:
name = 'TrackedEntityNode'
model = TrackedEntityModel
class Request(SQLAlchemyObjectType):
"""Request node."""
class Meta:
model = RequestModel
interfaces = (TrackedEntity,)
class User(SQLAlchemyObjectType):
"""User Node"""
class Meta:
model = UserModel
interfaces = (CustomNode,)
class CvFormFieldValueType(SQLAlchemyObjectType):
class Meta:
model = CvFormFieldValueTypeModel
interfaces = (ControlledVocabulary,)
common_field_kwargs = {'id': graphene.UUID(required=False), 'label': graphene.String(required=False)}
class Query(graphene.ObjectType):
"""Query objects for GraphQL API."""
node = CustomNode.Field()
te_node = TrackedEntity.Field()
cv_node = ControlledVocabulary.Field()
# Non-Tracked Entities:
users: List[User] = SQLAlchemyConnectionField(User)
# Generic Query for any Tracked Entity:
tracked_entities: List[TrackedEntity] = FilteredConnectionField(TrackedEntity, sort=None, filter=graphene.Argument(TrackedEntityInput))
# Generic Query for any Controlled Vocabulary:
cv: ControlledVocabulary = graphene.Field(ControlledVocabulary, controlled_vocabulary_type_id=graphene.UUID(required=False),
base_entry_key=graphene.String(required=False),
**common_field_kwargs)
cvs: List[ControlledVocabulary] = FilteredConnectionField(ControlledVocabulary, sort=None, filter=graphene.Argument(CvInput))
@staticmethod
def resolve_with_filters(info: ResolveInfo, model: Type[SQLAlchemyObjectType], **kwargs):
query = model.get_query(info)
log.debug(kwargs)
for filter_name, filter_value in kwargs.items():
model_filter_column = getattr(model._meta.model, filter_name, None)
log.debug(type(filter_value))
if not model_filter_column:
continue
if isinstance(filter_value, SQLAlchemyInputObjectType):
log.debug(True)
filter_model = filter_value.sqla_model
q = FilteredConnectionField.get_query(filter_model, info, sort=None, **kwargs)
# noinspection PyArgumentList
query = query.filter(model_filter_column == q.filter_by(**filter_value))
log.info(query)
else:
query = query.filter(model_filter_column == filter_value)
return query
def resolve_tracked_entity(self, info: ResolveInfo, **kwargs):
entity: TrackedEntity = Query.resolve_with_filters(info=info, model=BaseTrackedEntity, **kwargs).one()
return entity
def resolve_tracked_entities(self, info, **kwargs):
query = Query.resolve_with_filters(info=info, model=BaseTrackedEntity, **kwargs)
tes: List[BaseTrackedEntity] = query.all()
return tes
def resolve_cv(self, info, **kwargs):
cv: List[BaseControlledVocabulary] = Query.resolve_with_filters(info=info, model=BaseControlledVocabulary, **kwargs).one()
log.info(cv)
return cv
def resolve_cvs(self, info, **kwargs):
cv: List[BaseControlledVocabulary] = Query.resolve_with_filters(info=info, model=BaseControlledVocabulary, **kwargs).all()
return cv
我希望不能使用SQLAlchemyInterface扩展Node，而是将Node添加回TrackedEntity和ControlledVocabulary的接口列表中，但是能够执行如下查询：
schema = Schema(query=Query, types=[*tracked_members, *cv_members])