Simplifying Asynchronous Code in Python with async and await

Mar 17, 2024 ยท 2 min read

Async programming allows us to write non-blocking code that doesn't halt execution while waiting on long-running tasks like network requests or file I/O. This makes async ideal for Python web servers, scrapers, and other programs needing high throughput and scalability.

However, async code can get complex with many callback functions and promise-style coding. The async and await keywords introduced in Python 3.5 aim to simplify this.

How async/await Works

An async function is a special type that allows usage of the await keyword and handles concurrency differently:

import asyncio

async def fetch_data():
    print('fetching...')
    await asyncio.sleep(2) # pauses without blocking  
    print('done!')

asyncio.run(fetch_data())

The await pauses execution until the async operation completes, without halting the program. This makes async code read similarly to synchronous code, while still running concurrently.

Behind the scenes, the asyncio module manages switching between async tasks efficiently.

Key Benefits

  • More legible and idiomatic Python code
  • Avoid callback hell - no need to nest functions
  • Write synchronous-style code while still using non-blocking operations
  • Integrates well with async libraries like aiohttp
  • Practical Tips

  • Use asyncio.run to run async main functions
  • Handle exceptions properly with try/except blocks
  • Async code runs on a single thread, so use asyncio.create_task to spawn separate tasks
  • Use asyncio.gather to wait on multiple async operations
  • So in summary, async/await makes async programming far more straightforward in Python. The syntax unlocks the power of asynchronous frameworks with code that reads like it's synchronous. This helps developers write highly performant network apps without sacrificing code quality or maintainability.

    Browse by tags:

    Browse by language:

    The easiest way to do Web Scraping

    Get HTML from any page with a simple API call. We handle proxy rotation, browser identities, automatic retries, CAPTCHAs, JavaScript rendering, etc automatically for you


    Try ProxiesAPI for free

    curl "http://api.proxiesapi.com/?key=API_KEY&url=https://example.com"

    <!doctype html>
    <html>
    <head>
        <title>Example Domain</title>
        <meta charset="utf-8" />
        <meta http-equiv="Content-type" content="text/html; charset=utf-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1" />
    ...

    X

    Don't leave just yet!

    Enter your email below to claim your free API key: