Making Asynchronous HTTP Requests in Python without Waiting for a Response

Feb 3, 2024 ยท 2 min read

When making HTTP requests in Python, the default behavior is to make synchronous requests - the code waits and blocks until a response is received from the server before continuing execution. However, in some cases you may want to fire off requests without waiting for a response, allowing your code to continue processing in the background. Here are some ways to make asynchronous HTTP requests in Python without blocking.

Using the requests Library

The popular requests library provides a simple method called .get() or .post() to make synchronous requests. To make them non-blocking, you can use the .async variant:

import requests

async_req = requests.get('https://example.com', async=True)

This will immediately return a Response object without waiting for the request to complete. You won't have access to response data yet, but can continue other work while the request happens in the background.

Using the asyncio Module

Python's built-in asyncio module allows executing I/O-bound tasks asynchronously using async/await syntax:

import asyncio
import aiohttp

async def main():
    async with aiohttp.ClientSession() as session:
        async with session.get('https://api.example.com') as response:
             print("Requested!") 

asyncio.run(main())

The above code sends the request and prints "Requested!" without waiting for the response. The aiohttp library handles the asynchronous details.

Using Threads or Processes

You can also use threads or processes to make requests in parallel:

import requests
import threading

def async_request():
    requests.get('https://api.example.com')

t = threading.Thread(target=async_request)
t.start()

Here the async_request function runs in a separate thread, allowing the main thread to continue work.

The key in all cases is leveraging asynchronous programming to fire off non-blocking I/O requests. This frees up your Python code to continue processing without wasting cycles waiting for responses.

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