Async HTTP with aiohttp

Why aiohttp

The requestsrequests library is blocking.

For asyncio, you typically use:

aiohttpaiohttp

It supports non-blocking HTTP requests.

Basic GET

aiohttp_get.py

import asyncio
import aiohttp
 
 
async def main():
    timeout = aiohttp.ClientTimeout(total=10)
 
    async with aiohttp.ClientSession(timeout=timeout) as session:
        async with session.get("https://api.github.com") as resp:
            data = await resp.json()
            print(resp.status)
            print(list(data.keys())[:5])
 
 
asyncio.run(main())

aiohttp_get.py

import asyncio
import aiohttp
 
 
async def main():
    timeout = aiohttp.ClientTimeout(total=10)
 
    async with aiohttp.ClientSession(timeout=timeout) as session:
        async with session.get("https://api.github.com") as resp:
            data = await resp.json()
            print(resp.status)
            print(list(data.keys())[:5])
 
 
asyncio.run(main())

Fetch many URLs concurrently

aiohttp_many.py

import asyncio
import aiohttp
 
 
async def fetch(session: aiohttp.ClientSession, url: str) -> int:
    async with session.get(url) as resp:
        await resp.read()
        return resp.status
 
 
async def main():
    urls = [
        "https://httpbin.org/delay/1",
        "https://httpbin.org/delay/1",
        "https://httpbin.org/delay/1",
    ]
 
    timeout = aiohttp.ClientTimeout(total=5)
 
    async with aiohttp.ClientSession(timeout=timeout) as session:
        statuses = await asyncio.gather(*(fetch(session, u) for u in urls), return_exceptions=True)
        print(statuses)
 
 
asyncio.run(main())

aiohttp_many.py

import asyncio
import aiohttp
 
 
async def fetch(session: aiohttp.ClientSession, url: str) -> int:
    async with session.get(url) as resp:
        await resp.read()
        return resp.status
 
 
async def main():
    urls = [
        "https://httpbin.org/delay/1",
        "https://httpbin.org/delay/1",
        "https://httpbin.org/delay/1",
    ]
 
    timeout = aiohttp.ClientTimeout(total=5)
 
    async with aiohttp.ClientSession(timeout=timeout) as session:
        statuses = await asyncio.gather(*(fetch(session, u) for u in urls), return_exceptions=True)
        print(statuses)
 
 
asyncio.run(main())

Async HTTP with aiohttp

Why aiohttp

Basic GET

Fetch many URLs concurrently

Notes

🧪 Try It Yourself

Exercise 1 – Your First Coroutine

Exercise 2 – await asyncio.sleep

Exercise 3 – Gather Two Coroutines

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