python - 如何在 FastAPI 中对模型的所有字段启用过滤

Question

在带有 restframework 的 Django 中，你可以这样做:

class Item(models.Model):
    id = models.IntegerField()
    name = models.CharField(max_length=32)
    another_attribute = models.CharField(max_length=32)
    ...
    (more attributes)
    ...
    yet_another_attribute = models.CharField(max_length=32)

class ItemViewSet(viewsets.ReadOnlyModelViewSet):
    permission_classes = [IsAuthenticated]
    serializer_class = ItemSerializer
    filterset_fields = '__all__' # <- this enables filtering on all fields
    queryset = Item.objects.all()

如果我想允许过滤， filterset_fields = '__all__'会让我做类似 api/item/?(attribute)=(value) 的事情并允许我过滤任何属性
我正在阅读教程( https://fastapi.tiangolo.com/tutorial/sql-databases/#crud-utils )，看起来涉及很多手动过滤:

from fastapi_sqlalchemy import db

class Item(BaseModel):
    id: int
    name: str
    another_attribute: str
    ...
    (more attributes)
    ...
    yet_another_attribute: str

# is it necessary to manually include all the fields I want to filter on as optional query parameters?
@app.get("/items/")
async def read_item(
    db: Session,
    id: Optional[int] = None,
    name: Optional[str] = None,
    another_attribute: Optional[str] = None,
    ...
    (more attributes)
    ...
    yet_another_attribute: Optional[str] = None
):
    # and then I'd need to check if the query parameter has been specified, and if so, filter it.
    queryset = db.session.query(Item)
    if id:
        queryset = queryset.filter(Item.id == id)
    if name:
        queryset = queryset.filter(Item.name == name)
    if another_attribute:
        queryset = queryset.filter(Item.another_attribute == another_attribute)
    ...
    (repeat above pattern for more attributes)
    ...
    if yet_another_attribute:
        queryset = queryset.filter(Item.yet_another_attribute == yet_another_attribute)

实现上述行为的首选方法是什么？是否有任何软件包可以使我免于进行大量手动过滤，从而使我的行为与 Django Rest Framework View 集一样方便？
或者手动包含我想要过滤的所有字段作为可选查询参数，然后检查每个参数，然后过滤是否存在是唯一的方法？

Answer 1

这是可能的，但还不完美:

from fastapi.params import Depends

@app.get("/items/")
async def read_item(item: Item = Depends()):
    pass

见 FastAPI Doku详情。
缺点是可能需要在 Item 类中指定参数。可以使用所有可选参数编​​写子类(例如，如 here 所述)。它适用于类的实例，但 FastAPI 似乎没有反射(reflect) API 文档中的那些。如果有人有解决方案，我很乐意学习。
或者，您可以拥有多个模型，如 here 所述.但我不喜欢这种方法。
要回答您的第二个问题，您可以像这样访问所有通用参数:

@app.get("/items/")
async def read_item(
    db: Session,
    id: Optional[int] = None,
    name: Optional[str] = None,
    another_attribute: Optional[str] = None,
    ...
    (more attributes)
    ...
    yet_another_attribute: Optional[str] = None
):
    params = locals().copy()
    ...
    for attr in [x for x in params if params[x] is not None]:
        query = query.filter(getattr(db_model.Item, attr).like(params[attr]))