如何在 models.py 中制作装饰器？

Question

我的 django 模型中有一个足球队课程。我做了 3 种赢、平和输的方法，self.Points_of_the_season 将被相应地修改（+3 表示胜利，+1 表示平局，+0 表示失败）。但是当我编写这些方法时，我必须在每次调用这 3 个方法时更改 self.Match_Played。如何制作一个名为 @play_match 的装饰器，它将为相关字段添加 1？

这是models.py的代码：

class Team(models.Model):
    Team_name = models.CharField(max_length=255)
    Foundation_year = models.IntegerField()
    Points_of_season = models.IntegerField(default=0)
    Match_Played = models.IntegerField(default=0)
    League = models.ForeignKey(League, on_delete=models.CASCADE)

    def __str__(self):
        return f"{self.Team_name}-{self.Foundation_year}"

    @play_match
    def win(self):
        self.Points_of_season += 3

    @play_match
    def draw(self):
        self.Points_of_season += 1

    @play_match
    def lose(self):
        pass

Answer 1

像任何其他装饰器一样。装饰器函数的参数应该只是函数，然后你在装饰器函数中定义你的子函数，它将在执行你的函数之前进行“装饰”。所以在这种情况下，我的装饰器函数是play_match，它定义了add_one，它接受了self参数，因此它可以访问类变量。然后它增加 Match_Played 并调用传递给装饰器的函数。

class Team:
    Team_Name = ""
    Foundation_year = 0
    Points_of_season = 0
    Match_Played = 0
    League = "league"

    def __str__(self):
        return f"{self.Team_name}-{self.Foundation_year}"

    def play_match(func):
        def add_one(self):
            self.Match_Played += 1
            func(self)
        return add_one

    @play_match
    def win(self):
        self.Points_of_season += 3

    @play_match
    def draw(self):
        self.Points_of_season += 1

    @play_match
    def lose(self):
        pass

x = Team()
x.win()
print("Num matches: ", x.Match_Played)
x.draw()
print("Num matches: ", x.Match_Played)

输出：

Num matches:  1
Num matches:  2