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Merge pull request #5358 from burakcank/signal_coroutine 

Document coroutines for signals.
This commit is contained in:
Mikhail Korobov 2022-05-28 13:38:05 +05:00 committed by GitHub
parent 99cddecd28 a9dfd85ea6
commit bafe874ecc
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2 changed files with 11 additions and 11 deletions
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2
docs/topics/coroutines.rst
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@ -1,3 +1,5 @@
.. _topics-coroutines:
==========
Coroutines
==========

20
docs/topics/signals.rst
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@ -51,12 +51,12 @@ Deferred signal handlers
========================
Some signals support returning :class:`~twisted.internet.defer.Deferred`
objects from their handlers, allowing you to run asynchronous code that
does not block Scrapy. If a signal handler returns a
:class:`~twisted.internet.defer.Deferred`, Scrapy waits for that
:class:`~twisted.internet.defer.Deferred` to fire.
or :term:`awaitable objects <awaitable>` from their handlers, allowing
you to run asynchronous code that does not block Scrapy. If a signal
handler returns one of these objects, Scrapy waits for that asynchronous
operation to finish.
Let's take an example::
Let's take an example using :ref:`coroutines <topics-coroutines>`::
class SignalSpider(scrapy.Spider):
name = 'signals'
@ -68,17 +68,15 @@ Let's take an example::
crawler.signals.connect(spider.item_scraped, signal=signals.item_scraped)
return spider
def item_scraped(self, item):
async def item_scraped(self, item):
# Send the scraped item to the server
d = treq.post(
response = await treq.post(
'http://example.com/post',
json.dumps(item).encode('ascii'),
headers={b'Content-Type': [b'application/json']}
)
# The next item will be scraped only after
# deferred (d) is fired
return d
return response
def parse(self, response):
for quote in response.css('div.quote'):
@ -89,7 +87,7 @@ Let's take an example::
}
See the :ref:`topics-signals-ref` below to know which signals support
:class:`~twisted.internet.defer.Deferred`.
:class:`~twisted.internet.defer.Deferred` and :term:`awaitable objects <awaitable>`.
.. _topics-signals-ref: