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70 lines
2.4 KiB
Python
70 lines
2.4 KiB
Python
5 years ago
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# Copyright (c) 2012-2015 Denis Bilenko. See LICENSE for details.
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"""
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Native thread-based hostname resolver.
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"""
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import _socket
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from gevent.hub import get_hub
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__all__ = ['Resolver']
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class Resolver(object):
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"""
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Implementation of the resolver API using native threads and native resolution
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functions.
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Using the native resolution mechanisms ensures the highest
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compatibility with what a non-gevent program would return
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including good support for platform specific configuration
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mechanisms. The use of native (non-greenlet) threads ensures that
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a caller doesn't block other greenlets.
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This implementation also has the benefit of being very simple in comparison to
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:class:`gevent.resolver_ares.Resolver`.
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.. tip::
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Most users find this resolver to be quite reliable in a
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properly monkey-patched environment. However, there have been
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some reports of long delays, slow performance or even hangs,
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particularly in long-lived programs that make many, many DNS
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requests. If you suspect that may be happening to you, try the
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dnspython or ares resolver (and submit a bug report).
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"""
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def __init__(self, hub=None):
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if hub is None:
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hub = get_hub()
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self.pool = hub.threadpool
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if _socket.gaierror not in hub.NOT_ERROR:
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# Do not cause lookup failures to get printed by the default
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# error handler. This can be very noisy.
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hub.NOT_ERROR += (_socket.gaierror, _socket.herror)
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def __repr__(self):
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return '<%s.%s at 0x%x pool=%r>' % (type(self).__module__,
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type(self).__name__,
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id(self), self.pool)
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def close(self):
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pass
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# from briefly reading socketmodule.c, it seems that all of the functions
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# below are thread-safe in Python, even if they are not thread-safe in C.
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def gethostbyname(self, *args):
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return self.pool.apply(_socket.gethostbyname, args)
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def gethostbyname_ex(self, *args):
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return self.pool.apply(_socket.gethostbyname_ex, args)
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def getaddrinfo(self, *args, **kwargs):
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return self.pool.apply(_socket.getaddrinfo, args, kwargs)
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def gethostbyaddr(self, *args, **kwargs):
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return self.pool.apply(_socket.gethostbyaddr, args, kwargs)
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def getnameinfo(self, *args, **kwargs):
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return self.pool.apply(_socket.getnameinfo, args, kwargs)
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