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84 lines
2.8 KiB
Python
84 lines
2.8 KiB
Python
import asyncio
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from contextlib import suppress
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from twisted.internet import asyncioreactor, error
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from scrapy.utils.misc import load_object
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def listen_tcp(portrange, host, factory):
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"""Like reactor.listenTCP but tries different ports in a range."""
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from twisted.internet import reactor
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if len(portrange) > 2:
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raise ValueError("invalid portrange: %s" % portrange)
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if not portrange:
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return reactor.listenTCP(0, factory, interface=host)
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if not hasattr(portrange, '__iter__'):
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return reactor.listenTCP(portrange, factory, interface=host)
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if len(portrange) == 1:
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return reactor.listenTCP(portrange[0], factory, interface=host)
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for x in range(portrange[0], portrange[1] + 1):
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try:
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return reactor.listenTCP(x, factory, interface=host)
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except error.CannotListenError:
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if x == portrange[1]:
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raise
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class CallLaterOnce:
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"""Schedule a function to be called in the next reactor loop, but only if
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it hasn't been already scheduled since the last time it ran.
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"""
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def __init__(self, func, *a, **kw):
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self._func = func
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self._a = a
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self._kw = kw
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self._call = None
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def schedule(self, delay=0):
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from twisted.internet import reactor
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if self._call is None:
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self._call = reactor.callLater(delay, self)
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def cancel(self):
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if self._call:
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self._call.cancel()
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def __call__(self):
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self._call = None
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return self._func(*self._a, **self._kw)
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def install_reactor(reactor_path):
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"""Installs the :mod:`~twisted.internet.reactor` with the specified
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import path."""
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reactor_class = load_object(reactor_path)
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if reactor_class is asyncioreactor.AsyncioSelectorReactor:
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with suppress(error.ReactorAlreadyInstalledError):
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asyncioreactor.install(asyncio.get_event_loop())
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else:
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*module, _ = reactor_path.split(".")
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installer_path = module + ["install"]
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installer = load_object(".".join(installer_path))
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with suppress(error.ReactorAlreadyInstalledError):
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installer()
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def verify_installed_reactor(reactor_path):
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"""Raises :exc:`Exception` if the installed
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:mod:`~twisted.internet.reactor` does not match the specified import
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path."""
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from twisted.internet import reactor
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reactor_class = load_object(reactor_path)
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if not isinstance(reactor, reactor_class):
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msg = "The installed reactor ({}.{}) does not match the requested one ({})".format(
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reactor.__module__, reactor.__class__.__name__, reactor_path
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)
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raise Exception(msg)
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def is_asyncio_reactor_installed():
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from twisted.internet import reactor
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return isinstance(reactor, asyncioreactor.AsyncioSelectorReactor)
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