装饰器实现flask登录，没登录不让看index页面，多个装饰器装饰一个函数的执行顺序

一、装饰器实现flask登录，没登录不让看index页面
from flask import Flask, render_template, request, redirect, Markup, session

# PEP8
app = Flask(__name__)  # 实例化flask对象
app.secret_key = "123asdzxc"    #这个必须写，不然没有session

STUDENT_DICT = {
    1: {'name': 'Old', 'age': 38, 'gender': '中'},
    2: {'name': 'Boy', 'age': 73, 'gender': '男'},
    3: {'name': 'EDU', 'age': 84, 'gender': '女'},
}

def wai(func):
    def inner(*args,**kwargs):
        if not session.get("user"):
            return redirect("/login")

        else:
            return func(*args,**kwargs)
    return inner


@app.template_global()
def a_b(a, b):
    return a * b


@app.template_filter()
def a_b_c(a, b, c):
    return a * b * c


@app.route("/index")
@wai
def index():
    btn = "<a href='/add_stu'>添加学生</a>"
    btn = Markup(btn)
    return render_template("index.html", stu=STUDENT_DICT, btn=btn)


@app.route("/login", methods=["POST", "GET"])
def login():
    print(request.method)  # 获得当前请求的方式
    if request.method == "GET":
        # print(request.args["id"])  # 获取GET请求时，URL参数
        # print(request.args.get("username"))  # 获取GET请求时，URL参数
        return render_template("login.html")

    if request.method == "POST":
        username = request.form["username"]  # 获取POST请求时，FormData中的参数
        password = request.form.get("password")
        if username == "alex" and password == "DSB":
            session["user"] = username
            return redirect("/index")
        else:
            return render_template("login.html", msg="用户名密码错")

    # print(request.values.to_dict())  # 坑FormData参数会被URL参数覆盖
    print(request.data)  # Content-Type: None
    print(request.json)  # Content-Type: application/json
    print(request.headers)  # 请求头
    print(request.url)  # url地址：http://127.0.0.1:9527/login?id=123&username=dsb
    print(request.path)  # /login
    print('6666')

    return render_template("login.html")


@app.route("/detail")
def detail():
    if request.method == "GET":
        id = request.args["id"]
        stu = STUDENT_DICT.get(int(id))
        return render_template("detail.html", stu=stu, id=id)


@app.route("/delete/<int:id>")
def delete(id):
    print(type(id), id)
    STUDENT_DICT.pop(id)

    return redirect("/index")


@app.route("/inc")
def inc():
    return render_template("inc.html", stu=STUDENT_DICT)


if __name__ == '__main__':
    app.run("0.0.0.0", 9527, debug=True)

二、多个装饰器装饰一个函数的执行顺序（day12）：

def wrapper1(func):  # func ==  f函数名    #哪个糖靠近被装饰函数，哪个语法糖函数就先执行，但是内部的inner却后执行
    print('进入wrapper1了')
    def inner1():
        print('inner1')  # 2
        func()       #这个函数func是被装饰的函数
        print('func1')  # 4
    return inner1      #@wrapper1最后一句f==inner1和@wrapper2后第一句f=wrapper2(f)，变量替换，inner1 = wrapper2(f),这样就执行下面的装饰器函数了

def wrapper2(func):  # func == inner1   上面返回一个inner1 = wrapper2(f)
    print('进入wrapper2了')
    def inner2():
        print('inner2')  # 1
        func()       #这里的func()其实是inner1(),到上面去了
        print('func2')  # 5
    return inner2
# @wrapper3
@wrapper2  #  f = wrapper2(f)  里面的f==inner1  外面的f == inner2
@wrapper1  # f = wrapper1(f)   里面的f==函数名f  外面的f == inner1
def f():  # 3
    print('主函数')

f()  # inner2()