Code-Memo

Asynchronous Programming

async and await Syntax

• async def: Declares a coroutine function, which can use await to suspend its execution until the result of an asynchronous operation is available.
• await: Suspends the execution of the coroutine until the awaited coroutine or Future completes and returns the result.

import asyncio

async def async_task():
    print("Task started")
    await asyncio.sleep(1)
    print("Task completed")

# Running an asynchronous coroutine
asyncio.run(async_task())

Handling Asynchronous I/O Operations

Asynchronous I/O operations involve tasks that wait for external resources (e.g., network requests, file operations). Asyncio provides mechanisms to handle these operations efficiently without blocking the event loop.

Example: Asynchronous HTTP Request with aiohttp

import aiohttp
import asyncio

async def fetch_data(url):
    async with aiohttp.ClientSession() as session:
        async with session.get(url) as response:
            return await response.text()

async def main():
    url = 'https://jsonplaceholder.typicode.com/posts/1'
    response = await fetch_data(url)
    print(response)

asyncio.run(main())

Explanation:

• aiohttp.ClientSession: Manages HTTP connections and provides a context manager for making HTTP requests asynchronously.
• session.get(url): Initiates an asynchronous GET request to the specified URL.
• response.text(): Asynchronously retrieves and returns the response body as text.

Benefits of Asynchronous Programming

• Improved Efficiency: Non-blocking operations allow other tasks to run while waiting for I/O.
• Scalability: Handles large numbers of concurrent connections efficiently.
• Simplified Code: Avoids callback-based programming with clearer syntax using async and await.