Fix Python – How could I use requests in asyncio?

Question

Asked By – flyer

I want to do parallel http request tasks in asyncio, but I find that python-requests would block the event loop of asyncio. I’ve found aiohttp but it couldn’t provide the service of http request using a http proxy.

So I want to know if there’s a way to do asynchronous http requests with the help of asyncio.

Now we will see solution for issue: How could I use requests in asyncio?


Answer

To use requests (or any other blocking libraries) with asyncio, you can use BaseEventLoop.run_in_executor to run a function in another thread and yield from it to get the result. For example:

import asyncio
import requests

@asyncio.coroutine
def main():
    loop = asyncio.get_event_loop()
    future1 = loop.run_in_executor(None, requests.get, 'http://www.google.com')
    future2 = loop.run_in_executor(None, requests.get, 'http://www.google.co.uk')
    response1 = yield from future1
    response2 = yield from future2
    print(response1.text)
    print(response2.text)

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

This will get both responses in parallel.

With python 3.5 you can use the new await/async syntax:

import asyncio
import requests

async def main():
    loop = asyncio.get_event_loop()
    future1 = loop.run_in_executor(None, requests.get, 'http://www.google.com')
    future2 = loop.run_in_executor(None, requests.get, 'http://www.google.co.uk')
    response1 = await future1
    response2 = await future2
    print(response1.text)
    print(response2.text)

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

See PEP0492 for more.

This question is answered By – christian

This answer is collected from stackoverflow and reviewed by FixPython community admins, is licensed under cc by-sa 2.5 , cc by-sa 3.0 and cc by-sa 4.0