Using aiohttp

asyncio can achieve concurrent I/O operations in a single thread. While its power is somewhat limited on the client side, using asyncio on the server side, such as in a web server, allows for high concurrency with multiple users due to HTTP connections being I/O operations.

asyncio implements various protocols like TCP, UDP, and SSL, and aiohttp is an HTTP framework built on top of asyncio.

First, install aiohttp:

bash

$ pip install aiohttp

Next, let's write an HTTP server that handles the following URLs:

/ - Returns "Index Page".
/{name} - Returns the text "Hello, {name}!".

Here’s the code:

python

# app.py
from aiohttp import web

async def index(request):
    text = "<h1>Index Page</h1>"
    return web.Response(text=text, content_type="text/html")

async def hello(request):
    name = request.match_info.get("name", "World")
    text = f"<h1>Hello, {name}</h1>"
    return web.Response(text=text, content_type="text/html")

app = web.Application()

# Add routes:
app.add_routes([web.get("/", index), web.get("/{name}", hello)])

if __name__ == "__main__":
    web.run_app(app)

Run app.py directly and visit the homepage:

Accessing http://localhost:8080/Bob will return:

When using aiohttp, you define async functions to handle different URLs, add mappings through app.add_routes(), and finally start the entire processing flow using run_app().

Using aiohttp ​

Using aiohttp