如何从装饰器函数执行类方法

Question

I have a class with a main dictionary self.wardrobe , which is being saved to a JSON file by the method: self.save() .

I am now trying to make a decorator which calls the self.save() , method after executing the decorated method.

Thanks in advance:)

Edit:

This is a try defining the decorator outside of the class (I also tried @staticmethod but it didn't work somehow):

def decorate_save(func):
    def inner(*args, **kwargs):
        val = func(*args, **kwargs)
        self.save()
        return val
    return inner()

Second Edit:

this is the part of the class important for this problem:

class Wardrobe:
    def __init__(self, filepath):
        self.filepath = filepath
        with open(self.filepath, 'r') as f:
            self.wardrobe = json.load(f)
        # self.wardobe is a dict

    def duplicate(self, index: int):
        item = self.wardrobe['all'][index]
        self.wardrobe['all'].append(item) # self.wardrobe['all'] is a list

    def save(self):
        with open(self.filepath, 'w') as f:
            json.dump(self.wardrobe, f, indent=4)

Summary: I want to create a decorator for the method duplicate() , which executes the method save() right after.

(of course I have other functions than duplicate() , which need to save afterwards too. thats why I dont just call save() in the method.)

Answer 1

When decorating a method self is the first argument passed to inner. You could do something like:

import json

def decorate_save(method):
    def inner(self, *args, **kwargs):
        val = method(self, *args, **kwargs)
        self.save()
        return val
    return inner

class Wardrobe:
    def __init__(self, filepath):
        self.filepath = filepath
        with open(self.filepath, 'r') as f:
            self.wardrobe = json.load(f)
        # self.wardobe is a dict

    @decorate_save
    def duplicate(self, index: int):
        item = self.wardrobe['all'][index]
        self.wardrobe['all'].append(item) # self.wardrobe['all'] is a list

    def save(self):
        with open(self.filepath, 'w') as f:
            json.dump(self.wardrobe, f, indent=4)

w = Wardrobe('input_nogit.json')
w.duplicate(1)

Input json:

{
    "all": [
        "socks",
        "sandals"
    ]
}

Output json:

{
    "all": [
        "socks",
        "sandals",
        "sandals"
    ]
}