Source code for gevent.resolver.thread

# Copyright (c) 2012-2015 Denis Bilenko. See LICENSE for details.
"""
Native thread-based hostname resolver.
"""
import _socket

from gevent.hub import get_hub


__all__ = ['Resolver']


# trigger import of encodings.idna to avoid https://github.com/gevent/gevent/issues/349
u'foo'.encode('idna')


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