Low-level HTTP Server

.. currentmodule:: aiohttp.server

Note

This topic describes the low-level HTTP support. For high-level interface please take a look on :mod:`aiohttp.web`.

Run a basic server

Start implementing the basic server by inheriting the :class:`ServerHttpProtocol` object. Your class should implement the only method :meth:`ServerHttpProtocol.handle_request` which must be a coroutine to handle requests asynchronously

from urllib.parse import urlparse, parse_qsl

import aiohttp
import aiohttp.server
from aiohttp import MultiDict


import asyncio

class HttpRequestHandler(aiohttp.server.ServerHttpProtocol):

  async def handle_request(self, message, payload):
      response = aiohttp.Response(
          self.writer, 200, http_version=message.version
      )
      response.add_header('Content-Type', 'text/html')
      response.add_header('Content-Length', '18')
      response.send_headers()
      response.write(b'<h1>It Works!</h1>')
      await response.write_eof()

The next step is to create a loop and register your handler within a server. :exc:`KeyboardInterrupt` exception handling is necessary so you can stop your server with Ctrl+C at any time.

if __name__ == '__main__':
    loop = asyncio.get_event_loop()
    f = loop.create_server(
        lambda: HttpRequestHandler(debug=True, keep_alive=75),
        '0.0.0.0', '8080')
    srv = loop.run_until_complete(f)
    print('serving on', srv.sockets[0].getsockname())
    try:
        loop.run_forever()
    except KeyboardInterrupt:
        pass

Headers

Data is passed to the handler in the message, while request body is passed in payload param. HTTP headers are accessed through headers member of the message. To check what the current method of the request is use the method member of the message. It should be one of GET, POST, PUT or DELETE strings.

Handling GET params

Currently aiohttp does not provide automatic parsing of incoming GET params. However aiohttp does provide a nice :class:`MulitiDict` wrapper for already parsed params.

from urllib.parse import urlparse, parse_qsl

from aiohttp import MultiDict

class HttpRequestHandler(aiohttp.server.ServerHttpProtocol):

    async def handle_request(self, message, payload):
        response = aiohttp.Response(
            self.writer, 200, http_version=message.version
        )
        get_params = MultiDict(parse_qsl(urlparse(message.path).query))
        print("Passed in GET", get_params)

Handling POST data

POST data is accessed through the payload.read() generator method. If you have form data in the request body, you can parse it in the same way as GET params.

from urllib.parse import urlparse, parse_qsl

from aiohttp import MultiDict

class HttpRequestHandler(aiohttp.server.ServerHttpProtocol):

    async def handle_request(self, message, payload):
        response = aiohttp.Response(
            self.writer, 200, http_version=message.version
        )
        data = await payload.read()
        post_params = MultiDict(parse_qsl(data))
        print("Passed in POST", post_params)

SSL

To use asyncio's SSL support, just pass an SSLContext object to the :meth:`asyncio.BaseEventLoop.create_server` method of the loop.

import ssl

sslcontext = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
sslcontext.load_cert_chain('sample.crt', 'sample.key')

loop = asyncio.get_event_loop()
loop.create_server(lambda: handler, "0.0.0.0", "8080", ssl=sslcontext)

Reference

.. automodule:: aiohttp.server
    :members:
    :undoc-members:
    :show-inheritance:

.. disqus::