如何加快 python 中 rest api 的开发速度？

Question

我正在尝试使用 FastApi 和 sqlAchemy 创建后端应用程序。我有很多与数据库有关系的实体。所以，我的问题是：如何加快发展？现在我为每个实体代码编写：

@app.get("/holidays")
def getHolidays():
    session = Session(bind=engine)
    holidays: List[Holiday] = session.query(Holiday).all()
    return [x.to_json() for x in holidays]

@app.get("/exclusive_operations")
def getExclusiveOperations():
    session = Session(bind=engine)
    exclusive_operations: List[ExclusiveOperation] = session.query(ExclusiveOperation).all()
    return [x.to_json() for x in exclusive_operations]

@app.get('/category_descriptions')
def getCategoryDescr():
    session = Session(bind=engine)
    category_descrs: List[CategoryDescr] = session.query(CategoryDescr).all()
    return [x.to_json() for x in category_descrs]

所以如果我想创建所有的 crud 操作，我需要为 3 个实体创建 12 个典型方法。也许存在其他解决方案？

Answer 1

它是Python - 作为一种动态语言，函数和方法是在运行时创建的。 “@app.get”装饰器用于在应用程序中注册您的视图，而不是它们存在于模块的顶层。

因此，您可以创建一个 for 循环，为每个实体简单地重新创建和注册视图 - 它可以在模块级别或在函数内部完成。

（很高兴记住“@xxxx”装饰器语法只是调用装饰器的语法糖，将装饰函数作为唯一参数传递）

for Entity, name in [(Holiday, "holidays"), (ExclusiveOperation, "exclusive_operations"), (CategoryDescr, "category_descriptions")]:
    def freeze_var_wrapper(Entity, name): 
        # this intermediary function is needed, otherwise the Entity and name
        # variables would be always up-to-date inside the view function
        # and always point to the last value in the external for-loop after
        # it finished execution:
        def view():
            session = Session(bind=engine)
            entities = session.query(Entity).all()
            return [x.to_json() for x in entities]
        # optional, may facilitate debugging:
        view.__name__ = f"get{Entity.__name__}s"
        # actually registers the view function with the framework:
        # (could be done in the same line, without the "view_registrer" var)
        view_registrer = app.get(f"/{name}")
        view_registrer(view)
    
    freeze_var_wrapper(Entity, name)

还有其他方法可以删除样板并看起来更优雅 - 例如 class 继承和适当的 __init__subclass__ 在基础 class 中（即使框架不使用“class 视图”，我们也会为每个 class 注册绑定方法，这只是一个可调用的）：


class BaseView:
    Entity: cls 
    view_name: str

    def __init_subclass__(cls, *args, **kw):
        super().__init_subclass__(*args, **kw)
        app.get(f"/{cls.view_name}")(cls.view)
        # above, cls.view is bound to the subclass being processed, therefore 
        # the class attributes as defined in each class body are used inside the method

        # this could easily register post, delete and detail views as well
        
    @classmethod
    def view(cls);
        session = Session(bind=engine)
        entities = session.query(cls.Entity).all()
        return [x.to_json() for x in entities]
    
class HolydayView(BaseView):
    Entity = Holyday
    view_name = "holydays"
    # thats is just it.

class ExclusiveOperationView(BaseView):
    Entity = ExclusiveOperation
    view_name = "exclusive_operations"
    
class CatewgoryDescriptionView(BaseView):
    Entity = CategoryDescription
    view_name = "category_descriptions"

如何加快 python 中 rest api 的开发速度？

How to speed up development of rest api in python?

python

sqlalchemy

fastapi