How to decorate a function and get a class in python

January 22, 2022

I am trying to decorate a function and make the decorator convert it into a class.

I currently have a class like this:

class Licht(BaseCore):
    topics = ["glados/tcs/licht/set"]

    @classmethod
    def run(cls, topic, payload):
        mqtt_publish("tcs/bus/cmd", "1200")

and I try to decorate it, so that it looks nicer:

@core_factory(["glados/tcs/licht/set"])
def Licht(topic, payload):
    mqtt_publish("tcs/bus/cmd", "1200")

This is my current decorator code which doesn’t work:

def core_factory(topics):
    class NewCore(BaseCore):
        topics = topics
    def inner(func):
        import types
        NewCore.run = types.MethodType(lambda cls, topic, payload: func(topic, payload), BaseCore)
        return NewCore
    return inner

Is there a way to achieve this?

>Solution :

Your decorator should return a function that takes the decorated function and creates a class whose run method just calls the decorated function.

def core_factory(topics):
    def wrapper(f):

        class _(BaseCore):
            @classmethod
            def run(cls, topic, payload):
                return f(topic, payload)

        _.topics = topics
        _.__name__ = f.__name__

        return _
    return wrapper

@core_factory(["glados/tcs/licht/set"])
def Licht(topic, payload):
    mqtt_publish("tcs/bus/cmd", "1200")