asyncio — Scrapy documentation
New in version 2.0.
Installing the asyncio reactor
asyncio support, set the :setting:`TWISTED_REACTOR` setting to
If you are using
CrawlerRunner, you also need to install the
AsyncioSelectorReactor reactor manually. You can do that using
Using custom asyncio loops
You can also use custom asyncio event loops with the asyncio reactor. Set the :setting:`ASYNCIO_EVENT_LOOP` setting to the import path of the desired event loop class to use it instead of the default asyncio event loop.
Awaiting on Deferreds
When the asyncio reactor isn’t installed, you can await on Deferreds in the coroutines directly. When it is installed, this is not possible anymore, due to specifics of the Scrapy coroutine integration (the coroutines are wrapped into
asyncio.Future objects, not into
Deferred directly), and you need to wrap them into Futures. Scrapy provides two helpers for this:
If you need to use these functions in code that aims to be compatible with lower versions of Scrapy that do not provide these functions, down to Scrapy 2.0 (earlier versions do not support
asyncio), you can copy the implementation of these functions into your own code.