An example of how to setup event handlers in Python

event_handler_example.py

import requests


class Event:
    """An Event that gets triggered when an HTTP event occurs."""

    def __init__(self):
        self._event_handlers = []

    def __iadd__(self, handler):
        self._event_handlers.append(handler)
        return self

    def __isub__(self, handler):
        self._event_handlers.remove(handler)
        return self

    def __call__(self, *args, **kwargs):
        for event_handler in self._event_handlers:
            event_handler(*args, **kwargs)


class RequestEvent(Event):
    """An event that gets triggered when an HTTP request begins."""

    pass


class ResponseEvent(Event):
    """An event that gets triggered when an HTTP request is returned."""

    pass


class Client:
    """A client object for making HTTP calls."""

    def __init__(self, api_key=None):
        self.api_key = api_key
        self._request_event = RequestEvent()
        self._response_event = ResponseEvent()

    def make_request(self):
        """Make an HTTP request, fire off hooks for the request and response."""
        method = "GET"
        url = "https://example.com"
        data = None

        self._request_event(method=method, url=url, data=data)
        response = requests.request(method=method, url=url, json=data)
        self._response_event(
            method=method, url=url, data=data, http_status=response.status_code
        )

        return response.text

    def add_request_event_subscriber(self, function):
        """Add functions to fire when a request event occurs."""
        self._request_event += function

    def remove_request_event_subscriber(self, function):
        """Remove functions from firing when a request even occurs."""
        self._request_event -= function

    def add_response_event_subscriber(self, function):
        """Add functions to fire when a response event occurs."""
        self._response_event += function

    def remove_response_event_subscriber(self, function):
        """Remove functions from firing when a response even occurs."""
        self._response_event -= function


def custom_request_hook(**kwargs):
    """User-defined code that fires once a request hook occurs."""
    print("\nA request hook was fired!")
    print(f"URL used for request: {kwargs.get('url')}")
    print(f"Method used for request: {kwargs.get('method')}")
    print(f"Data used for request: {kwargs.get('data')}")


def custom_response_hook(**kwargs):
    """User-defined code that fires once a response hook occurs."""
    print("\nA response hook was fired!")
    print(f"The status code of the response: {kwargs.get('http_status')}")


def main():
    client = Client(123)

    # Subscribe to request events
    # You could subscribe once and call multiple requests and each time the hook would fire
    client.add_request_event_subscriber(custom_request_hook)
    client.add_response_event_subscriber(custom_response_hook)
    response = client.make_request()
    # print(response)

    # Unsubscribe from the request events
    client.remove_request_event_subscriber(custom_request_hook)
    client.remove_response_event_subscriber(custom_response_hook)
    response = client.make_request()
    # print(response)


if __name__ == "__main__":
    main()