Fetching data asynchronously from multiple URLs using Python async IO

Last update on April 24 2025 12:41:45 (UTC/GMT +8 hours)

4. Concurrent URL Fetcher

Write a Python program that implements a coroutine to fetch data from two different URLs simultaneously using the "aiohttp" library.

Sample Solution:

Code:

import asyncio
import aiohttp
async def fetch_url(url):
    async with aiohttp.ClientSession() as session:
        async with session.get(url) as response:
            return await response.text()
async def main():
    url_1 = "https://www.wikipedia.org/"
    url_2 = "https://www.google.com"    
    task1 = asyncio.create_task(fetch_url(url_1))
    task2 = asyncio.create_task(fetch_url(url_2))    
    data1 = await task1
    data2 = await task2    
    print("Data from ",url_1, len(data1), "bytes")
    print("Data from ",url_2, len(data2), "bytes")
# Run the event loop
asyncio.run(main())

Output:

Data from  https://www.wikipedia.org/ 74154 bytes
Data from  https://www.google.com 18273 bytes

Explanation:

In the above exercise-

The "fetch_url()" function coroutine is defined to asynchronously fetch data from a given URL using the 'aiohttp' library. It uses an aiohttp.ClientSession() to manage the HTTP requests and responses. The 'async' with syntax ensures that the session is properly closed.
The main coroutine is defined to run asynchronous operations. It creates two tasks using asyncio.create_task() that execute the fetch_url coroutine concurrently for two different URLs.
The 'await' keyword is used to wait for the completion of each task, storing the fetched data in data1 and data2.
Finally, the program prints the size of the fetched data from both URLs.

Flowchart:

For more Practice: Solve these Related Problems:

Write a Python program that uses aiohttp to asynchronously fetch data from two different URLs and prints the status code of each response.
Write a Python script to define a coroutine that concurrently retrieves content from two URLs using aiohttp, then prints the lengths of the responses.
Write a Python function that concurrently fetches JSON data from two URLs with aiohttp, merges the results, and prints the combined data.
Write a Python program to implement two asynchronous functions using aiohttp that fetch data from separate endpoints concurrently, then log the time taken for both requests.

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