Welcome to AIOHTTP — aiohttp 3.4.4 documentation

Key Features¶

Supports both Client and HTTP Server.
Supports both Server WebSockets and Client WebSockets out-of-the-box without the Callback Hell.
Web-server has Middlewares, Signals and pluggable routing.

Library Installation¶

$ pip install aiohttp

You may want to install optional cchardet library as faster replacement for chardet:

$ pip install cchardet

For speeding up DNS resolving by client API you may install aiodns as well. This option is highly recommended:

$ pip install aiodns

Getting Started¶

Client example:

import aiohttp
import asyncio

async def fetch(session, url):
    async with session.get(url) as response:
        return await response.text()

async def main():
    async with aiohttp.ClientSession() as session:
        html = await fetch(session, 'http://python.org')
        print(html)

loop = asyncio.get_event_loop()
loop.run_until_complete(main())

Server example:

from aiohttp import web

async def handle(request):
    name = request.match_info.get('name', "Anonymous")
    text = "Hello, " + name
    return web.Response(text=text)

app = web.Application()
app.add_routes([web.get('/', handle),
                web.get('/{name}', handle)])

web.run_app(app)

For more information please visit Client and Server pages.

What’s new in aiohttp 3?¶

Go to What’s new in aiohttp 3.0 page for aiohttp 3.0 major release changes.

Tutorial¶

Polls tutorial

Source code¶

The project is hosted on GitHub

Please feel free to file an issue on the bug tracker if you have found a bug or have some suggestion in order to improve the library.

The library uses Travis for Continuous Integration.

Dependencies¶

Python 3.5.3+
async_timeout
attrs
chardet
multidict
yarl
Optional cchardet as faster replacement for chardet.

Install it explicitly via:
```
$ pip install cchardet
```
Optional aiodns for fast DNS resolving. The library is highly recommended.
```
$ pip install aiodns
```

Communication channels¶

aio-libs google group: https://groups.google.com/forum/#!forum/aio-libs

Feel free to post your questions and ideas here.

gitter chat https://gitter.im/aio-libs/Lobby

We support Stack Overflow. Please add aiohttp tag to your question there.

Contributing¶

Please read the instructions for contributors before making a Pull Request.

Authors and License¶

The aiohttp package is written mostly by Nikolay Kim and Andrew Svetlov.

It’s Apache 2 licensed and freely available.

Feel free to improve this package and send a pull request to GitHub.

Policy for Backward Incompatible Changes¶

aiohttp keeps backward compatibility.

After deprecating some Public API (method, class, function argument, etc.) the library guaranties the usage of deprecated API is still allowed at least for a year and half after publishing new release with deprecation.

All deprecations are reflected in documentation and raises DeprecationWarning.

Sometimes we are forced to break the own rule for sake of very strong reason. Most likely the reason is a critical bug which cannot be solved without major API change, but we are working hard for keeping these changes as rare as possible.

Welcome to AIOHTTP¶