Python check if event

[Example code]-Python if condition to check if event has a element

How to test if event contains body json element? I get the following error [ERROR] KeyError: ‘body’ . I want to ensure that even curl can call lambda function as well as other lambda functions can call this lambda. But when the request is not through curl, then there is no body element hence I’m trying to create a if condition to set variables.

from modules.ZabbixSender import ZabbixSender import json def lambda_handler(event, context): print(event) if event["body"]: // KEY ERROR requestBody = json.loads(event["body"]) else: requestBody = json.loads(event) print(requestBody) Host = requestBody['Host'] Key = requestBody['Key'] Value = requestBody['Value'] sender = ZabbixSender("10.10.10.10", 10051) sender.add(Host, Key, Value) sender.send() return < "statusCode": 200, "headers": < "Content-Type": "application/json" >, "body": json.dumps(< "Host": Host, "Key" : Key, "Value" : Value, "Status": "Successfully updated Zabix Server" >) > 

If event is a dictionary you could simply use the get method on dictionaries. Like this:

if event.get("body"): requestBody = json.loads(event["body"]) else: requestBody = json.loads(event) 

or event better you could drop this into a one-liner:

requestBody = json.loads(event["body"]) if event.get("body") else json.loads(event) 

In this way if the key exists on the dictionary it will return the value of the key, otherwise it will return None . This should give you the behavior that you expect.

EnriqueBet 1422

if "body" in event: requestBody = json.loads(event["body"]) else: requestBody = json.loads(event) 

requestBody = json.loads(event["body"]) if "body" in event else json.loads(event) 

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Как определить и обрабатывать события в Python

Освойте обработку событий в Python с помощью разных библиотек (Pygame, Tkinter, asyncio) в нашей практической статье для новичков!

События в программировании являются ключевым аспектом для создания интерактивных приложений. В этой статье мы рассмотрим, как определить и обрабатывать события в Python с использованием различных библиотек и подходов.

Pygame

Pygame — это популярная библиотека для создания видеоигр и мультимедийных приложений на Python. Она предоставляет удобные инструменты для работы с графикой, звуком и вводом. Давайте рассмотрим пример обработки событий клавиатуры и мыши с помощью Pygame.

import pygame pygame.init() screen = pygame.display.set_mode((800, 600)) running = True while running: for event in pygame.event.get(): if event.type == pygame.QUIT: running = False elif event.type == pygame.KEYDOWN: if event.key == pygame.K_ESCAPE: running = False elif event.type == pygame.MOUSEBUTTONDOWN: print("Мышь нажата:", event.button, "Координаты:", event.pos) screen.fill((255, 255, 255)) pygame.display.flip() pygame.quit()

В этом примере мы создаем окно с помощью Pygame и используем цикл for для получения списка событий, происходящих в приложении. Затем мы обрабатываем различные типы событий, такие как закрытие окна, нажатие клавиш и нажатие кнопок мыши.

Tkinter

Tkinter — это стандартная библиотека Python для создания графических пользовательских интерфейсов (GUI). Она включена в большинство дистрибутивов Python и обеспечивает простой и нативный способ создания оконных приложений. Давайте рассмотрим пример обработки событий кнопки с помощью Tkinter.

import tkinter as tk def on_button_click(): print("Кнопка нажата!") root = tk.Tk() button = tk.Button(root, text="Нажми меня!", command=on_button_click) button.pack() root.mainloop()

В этом примере мы создаем окно с помощью Tkinter и добавляем в него кнопку. Мы также определяем функцию on_button_click , которая будет вызываться при нажатии на кнопку. Затем мы связываем эту функцию с кнопкой с помощью аргумента command .

😉 Не забывайте, что в Tkinter существует множество других виджетов, таких как текстовые поля, флажки и списки, которые также могут генерировать события.

Обработка событий асинхронно

Иногда вам может потребоваться обрабатывать события асинхронно, например, при работе с сетевыми запросами или другими операциями, которые могут занимать некоторое время. В этом случае вы можете использовать асинхронное программирование на Python с помощью библиотеки asyncio .

import asyncio async def handle_event(event): print("Обработка события:", event) await asyncio.sleep(2) print("Событие обработано:", event) async def main(): event_queue = asyncio.Queue() for i in range(5): await event_queue.put(i) tasks = [handle_event(await event_queue.get()) for _ in range(5)] await asyncio.gather(*tasks) asyncio.run(main())

В этом примере мы создаем асинхронную функцию handle_event , которая обрабатывает событие и имитирует затраты времени с помощью asyncio.sleep . Затем мы создаем очередь событий event_queue и наполняем ее несколькими событиями. В функции main мы создаем список задач для обработки событий и выполняем их параллельно с помощью asyncio.gather .

🚀 В заключение, обработка событий в Python может быть выполнена различными способами, в зависимости от используемых библиотек и подходов. Это делает Python гибким инструментом для разработки разнообразных приложений, от простых консольных программ до сложных графических интерфейсов и асинхронных систем.

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Threading Event Object In Python

You can use an Event Object in Python via the threading.Event class.

In this tutorial you will discover how to use an event object in Python.

Need for an Event Object

A thread is a thread of execution in a computer program.

Every Python program has at least one thread of execution called the main thread. Both processes and threads are created and managed by the underlying operating system.

Sometimes we may need to create additional threads in our program in order to execute code concurrently.

Python provides the ability to create and manage new threads via the threading module and the threading.Thread class.

You can learn more about Python threads in the guude:

In concurrent programming in threads, sometimes we need to coordinate threads with a boolean variable. This might be to trigger an action or signal some result.

This could be achieved with a mutual exclusion lock (mutex) and a boolean variable, but provides no way for threads to wait for the variable to be set True.

Instead, this can be achieved using an event object.

What is an event object and how can we use it in Python?

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How to Use an Event Object

Python provides an event object via the threading.Event class.

An event is a simple concurrency primitive that allows communication between threads.

A threading.Event object wraps a boolean variable that can either be “set” (True) or “not set” (False). Threads sharing the event instance can check if the event is set, set the event, clear the event (make it not set), or wait for the event to be set.

The threading.Event provides an easy way to share a boolean variable between threads that can act as a trigger for an action.

This is one of the simplest mechanisms for communication between threads: one thread signals an event and other threads wait for it.

— Event Objects, threading — Thread-based parallelism

First, an event object must be created and the event will be in the “not set” state.

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