Function deferred_to_future

scrapy/utils/defer.py:469–496

Return an :class:`asyncio.Future` object that wraps *d*. This function requires :class:`~twisted.internet.asyncioreactor.AsyncioSelectorReactor` to be installed. When :ref:`using the asyncio reactor `, you cannot await on :class:`~twisted.internet.defer.Deferre

(d: Deferred[_T])

def deferred_to_future(d: Deferred[_T]) -> Future[_T]:
    """Return an :class:`asyncio.Future` object that wraps *d*.

    This function requires
    :class:`~twisted.internet.asyncioreactor.AsyncioSelectorReactor` to be
    installed.

    When :ref:`using the asyncio reactor <install-asyncio>`, you cannot await
    on :class:`~twisted.internet.defer.Deferred` objects from :ref:`Scrapy
    callables defined as coroutines <coroutine-support>`, you can only await on
    ``Future`` objects. Wrapping ``Deferred`` objects into ``Future`` objects
    allows you to wait on them::

        class MySpider(Spider):
            ...
            async def parse(self, response):
                additional_request = scrapy.Request('https://example.org/price')
                deferred = self.crawler.engine.download(additional_request)
                additional_response = await deferred_to_future(deferred)

    .. versionchanged:: 2.14
        This function no longer installs an asyncio loop if called before the
        Twisted asyncio reactor is installed. A :exc:`RuntimeError` is raised
        in this case.
    """
    if not is_asyncio_available():
        raise RuntimeError("deferred_to_future() requires AsyncioSelectorReactor.")
    return d.asFuture(asyncio.get_event_loop())


def maybe_deferred_to_future(d: Deferred[_T]) -> Deferred[_T] | Future[_T]: