aiohttp: Asynchronous HTTP Client/Server for Python and asyncio¶

HTTP client/server for asyncio and Python.

Key Features¶

Supports both Client Usage and HTTP Server.
Supports both Server WebSockets and Client WebSockets out-of-the-box.
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
import async_timeout

async def fetch(session, url):
    with async_timeout.timeout(10):
        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.router.add_get('/', handle)
app.router.add_get('/{name}', handle)

web.run_app(app)

Note

Throughout this documentation, examples utilize the async/await syntax introduced by PEP 492 that is only valid for Python 3.5+.

If you are using Python 3.4, please replace await with yield from and async def with a @coroutine decorator. For example, this:

async def coro(...):
    ret = await f()

should be replaced by:

@asyncio.coroutine
def coro(...):
    ret = yield from f()

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 3.4.2+
chardet
multidict
async_timeout
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.

Table Of Contents¶

To see the full table of contents open the link.