aiohttp 3.0.0

Async http client/server framework (asyncio)

Async http client/server framework

Key Features

• Supports both client and server side of HTTP protocol.

• Supports both client and server Web-Sockets out-of-the-box.

• Web-server has middlewares and pluggable routing.

Getting started

Client

To retrieve something from the web:

import aiohttp
import asyncio
import async_timeout

async def fetch(session, url):
    async 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)

if __name__ == '__main__':
    loop = asyncio.get_event_loop()
    loop.run_until_complete(main())

Server

This is simple usage example:

from aiohttp import web

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

async def wshandler(request):
    ws = web.WebSocketResponse()
    await ws.prepare(request)

    async for msg in ws:
        if msg.type == web.MsgType.text:
            await ws.send_str("Hello, {}".format(msg.data))
        elif msg.type == web.MsgType.binary:
            await ws.send_bytes(msg.data)
        elif msg.type == web.MsgType.close:
            break

    return ws


app = web.Application()
app.router.add_get('/echo', wshandler)
app.router.add_get('/', handle)
app.router.add_get('/{name}', handle)

web.run_app(app)

Documentation

https://aiohttp.readthedocs.io/

External links

• Third party libraries

• Built with aiohttp

• Powered by aiohttp

Feel free to make a Pull Request for adding your link to these pages!

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.

Requirements

• Python >= 3.5.3

• async-timeout

• chardet

• multidict

• yarl

Optionally you may install the cChardet and aiodns libraries (highly recommended for sake of speed).

License

aiohttp is offered under the Apache 2 license.

Keepsafe

The aiohttp community would like to thank Keepsafe (https://www.getkeepsafe.com) for it’s support in the early days of the project.

Source code

The latest developer version is available in a github repository: https://github.com/aio-libs/aiohttp

Benchmarks

If you are interested in by efficiency, AsyncIO community maintains a list of benchmarks on the official wiki: https://github.com/python/asyncio/wiki/Benchmarks

Changelog

3.0.0 (2018-02-12)

Features

• Speed up the PayloadWriter.write method for large request bodies. (#2126)

• StreamResponse and Response are now MutableMappings. (#2246)

• ClientSession publishes a set of signals to track the HTTP request execution. (#2313)

• Content-Disposition fast access in ClientResponse (#2455)

• Added support to Flask-style decorators with class-based Views. (#2472)

• Signal handlers (registered callbacks) should be coroutines. (#2480)

• Support async with test_client.ws_connect(...) (#2525)

• Introduce site and application runner as underlying API for web.run_app implementation. (#2530)

• Only quote multipart boundary when necessary and sanitize input (#2544)

• Make the aiohttp.ClientResponse.get_encoding method public with the processing of invalid charset while detecting content encoding. (#2549)

• Add optional configurable per message compression for ClientWebSocketResponse and WebSocketResponse. (#2551)

• Add hysteresis to StreamReader to prevent flipping between paused and resumed states too often. (#2555)

• Support .netrc by trust_env (#2581)

• Avoid to create a new resource when adding a route with the same name and path of the last added resource (#2586)

• MultipartWriter.boundary is str now. (#2589)

• Allow a custom port to be used by TestServer (and associated pytest fixtures) (#2613)

• Add param access_log_class to web.run_app function (#2615)

• Add ssl parameter to client API (#2626)

• Fixes performance issue introduced by #2577. When there are no middlewares installed by the user, no additional and useless code is executed. (#2629)

• Rename PayloadWriter to StreamWriter (#2654)

• New options reuse_port, reuse_address are added to run_app and TCPSite. (#2679)

• Use custom classes to pass client signals parameters (#2686)

• Use attrs library for data classes, replace namedtuple. (#2690)

• Pytest fixtures renaming (#2578)

Bugfixes

• Correctly process upgrade request from server to HTTP2. aiohttp does not support HTTP2 yet, the protocol is not upgraded but response is handled correctly. (#2277)

• Fix ClientConnectorSSLError and ClientProxyConnectionError for proxy connector (#2408)

• Fix connector convert OSError to ClientConnectorError (#2423)

• Fix connection attempts for multiple dns hosts (#2424)

• Fix writing to closed transport by raising asyncio.CancelledError (#2499)

• Fix warning in ClientSession.__del__ by stopping to try to close it. (#2523)

• Fixed race-condition for iterating addresses from the DNSCache. (#2620)

• Fix default value of access_log_format argument in web.run_app (#2649)

• Freeze sub-application on adding to parent app (#2656)

• Do percent encoding for .url_for() parameters (#2668)

• Correctly process request start time and multiple request/response headers in access log extra (#2641)

Improved Documentation

• Improve tutorial docs, using literalinclude to link to the actual files. (#2396)

• Small improvement docs: better example for file uploads. (#2401)

• Rename from_env to trust_env in client reference. (#2451)

• Fixed mistype in Proxy Support section where trust_env parameter was used in session.get(“http://python.org”, trust_env=True) method instead of aiohttp.ClientSession constructor as follows: aiohttp.ClientSession(trust_env=True). (#2688)

• Fix issue with unittest example not compiling in testing docs. (#2717)

Deprecations and Removals

• Simplify HTTP pipelining implementation (#2109)

• Drop StreamReaderPayload and DataQueuePayload. (#2257)

• Drop md5 and sha1 finger-prints (#2267)

• Drop WSMessage.tp (#2321)

• Drop Python 3.4 and Python 3.5.0, 3.5.1, 3.5.2. Minimal supported Python versions are 3.5.3 and 3.6.0. yield from is gone, use async/await syntax. (#2343)

• Drop aiohttp.Timeout and use async_timeout.timeout instead. (#2348)

• Drop resolve param from TCPConnector. (#2377)

• Add DeprecationWarning for returning HTTPException (#2415)

• send_str(), send_bytes(), send_json(), ping() and pong() are genuine async functions now. (#2475)

• Drop undocumented app.on_pre_signal and app.on_post_signal. Signal handlers should be coroutines, support for regular functions is dropped. (#2480)

• StreamResponse.drain() is not a part of public API anymore, just use await StreamResponse.write(). StreamResponse.write is converted to async function. (#2483)

• Drop deprecated slow_request_timeout param and **kwargs` from RequestHandler. (#2500)

• Drop deprecated resource.url(). (#2501)

• Remove %u and %l format specifiers from access log format. (#2506)

• Drop deprecated request.GET property. (#2547)

• Simplify stream classes: drop ChunksQueue and FlowControlChunksQueue, merge FlowControlStreamReader functionality into StreamReader, drop FlowControlStreamReader name. (#2555)

• Do not create a new resource on router.add_get(…, allow_head=True) (#2585)

• Drop access to TCP tuning options from PayloadWriter and Response classes (#2604)

• Drop deprecated encoding parameter from client API (#2606)

• Deprecate verify_ssl, ssl_context and fingerprint parameters in client API (#2626)

• Get rid of the legacy class StreamWriter. (#2651)

• Forbid non-strings in resource.url_for() parameters. (#2668)

• Deprecate inheritance from ClientSession and web.Application and custom user attributes for ClientSession, web.Request and web.Application (#2691)

• Drop resp = await aiohttp.request(…) syntax for sake of async with aiohttp.request(…) as resp:. (#2540)

• Forbid synchronous context managers for ClientSession and test server/client. (#2362)

Misc

• #2552