7.3. Callback

Important

EN: Callback
PL: Wyzwalacz

7.3.1. Solution

✘>>> from typing import Any, Callable
>>> from urllib.request import urlopen
>>>
>>>
>>> def fetch(url: str,
...           *,
...           on_success: Callable[[str], Any] = lambda response: ...,
...           on_error: Callable[[Exception], Any] = lambda exception: ...,
...           ) -> None:
...     try:
...         response = urlopen(url).read().decode('utf-8')
...     except Exception as error:
...         on_error(error)
...     else:
...         on_success(response)

Usage:

✘>>> def ok(response: str):
...     print(response[:100])
>>>
>>> def err(exception: Exception):
...     print(exception)
>>>
>>> fetch(url='https://python3.info', on_success=ok, on_error=err)


<!DOCTYPE html>
<html class="writer-html5" lang="en" data-content_root="./">
<head>
  <meta charse

7.3.2. Object

✘>>> import requests
>>> from http import HTTPStatus
>>>
>>>
>>> def http(obj):
...     response = requests.request(
...         method=obj.method,
...         data=obj.data,
...         path=obj.path)
...
...     if response == HTTPStatus.OK:
...         return obj.on_success(response)
...     else:
...         return obj.on_error(response)
>>>
>>>
>>> class Request:
...     method = 'GET'
...     path = '/index'
...     data = None
...
...     def on_success(self, response):
...         print('Success!')
...
...     def on_error(self, response):
...         print('Error')
>>>
>>> http(Request())