web | flask 修饰器实现原理

简单地说就是传递函数地址实现了一个调用的过程，具体看代码：

class NotFlask():
    def __init__(self):
        self.routes={}
        
    def route(self, route_str):
        def decorator(f):
            self.routes[route_str] = f
            print("in decorator")
            return f
        print("in route")
        return decorator
       
    def serve(self, path):
        view_function = self.routes.get(path)
        if view_function:
            return view_function()
        else:
            raise ValueError('Route "{}" has not been registered'.format(path))


app = NotFlask()      # 实例化一个对象
@app.route("/")       # 这里return了一个函数decorator(f)
def hello():          # 这里执行 decorator(hello)
    return ("Hello World!")

# 整个流程相当于 (app.route('/'))(def hello():xxxxx)   -->@指向的函数(def的函数)

print(app.serve('/'))

'''
in route
in decorator
Hello World!
'''

over.