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# -*- test-case-name: twisted.internet.test.test_resolver -*-
# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.
"""
IPv6-aware hostname resolution.
@see: L{IHostnameResolver}
"""
from __future__ import division, absolute_import
__metaclass__ = type
from socket import (getaddrinfo, AF_INET, AF_INET6, AF_UNSPEC, SOCK_STREAM,
SOCK_DGRAM, gaierror)
from zope.interface import implementer
from twisted.internet.interfaces import (IHostnameResolver, IHostResolution,
IResolverSimple, IResolutionReceiver)
from twisted.internet.error import DNSLookupError
from twisted.internet.defer import Deferred
from twisted.internet.threads import deferToThreadPool
from twisted.internet.address import IPv4Address, IPv6Address
from twisted.python.compat import nativeString
from twisted.internet._idna import _idnaBytes
from twisted.logger import Logger
@implementer(IHostResolution)
class HostResolution(object):
"""
The in-progress resolution of a given hostname.
"""
def __init__(self, name):
"""
Create a L{HostResolution} with the given name.
"""
self.name = name
_any = frozenset([IPv4Address, IPv6Address])
_typesToAF = {
frozenset([IPv4Address]): AF_INET,
frozenset([IPv6Address]): AF_INET6,
_any: AF_UNSPEC,
}
_afToType = {
AF_INET: IPv4Address,
AF_INET6: IPv6Address,
}
_transportToSocket = {
'TCP': SOCK_STREAM,
'UDP': SOCK_DGRAM,
}
_socktypeToType = {
SOCK_STREAM: 'TCP',
SOCK_DGRAM: 'UDP',
}
@implementer(IHostnameResolver)
class GAIResolver(object):
"""
L{IHostnameResolver} implementation that resolves hostnames by calling
L{getaddrinfo} in a thread.
"""
def __init__(self, reactor, getThreadPool=None, getaddrinfo=getaddrinfo):
"""
Create a L{GAIResolver}.
@param reactor: the reactor to schedule result-delivery on
@type reactor: L{IReactorThreads}
@param getThreadPool: a function to retrieve the thread pool to use for
scheduling name resolutions. If not supplied, the use the given
C{reactor}'s thread pool.
@type getThreadPool: 0-argument callable returning a
L{twisted.python.threadpool.ThreadPool}
@param getaddrinfo: a reference to the L{getaddrinfo} to use - mainly
parameterized for testing.
@type getaddrinfo: callable with the same signature as L{getaddrinfo}
"""
self._reactor = reactor
self._getThreadPool = (reactor.getThreadPool if getThreadPool is None
else getThreadPool)
self._getaddrinfo = getaddrinfo
def resolveHostName(self, resolutionReceiver, hostName, portNumber=0,
addressTypes=None, transportSemantics='TCP'):
"""
See L{IHostnameResolver.resolveHostName}
@param resolutionReceiver: see interface
@param hostName: see interface
@param portNumber: see interface
@param addressTypes: see interface
@param transportSemantics: see interface
@return: see interface
"""
pool = self._getThreadPool()
addressFamily = _typesToAF[_any if addressTypes is None
else frozenset(addressTypes)]
socketType = _transportToSocket[transportSemantics]
def get():
try:
return self._getaddrinfo(hostName, portNumber, addressFamily,
socketType)
except gaierror:
return []
d = deferToThreadPool(self._reactor, pool, get)
resolution = HostResolution(hostName)
resolutionReceiver.resolutionBegan(resolution)
@d.addCallback
def deliverResults(result):
for family, socktype, proto, cannoname, sockaddr in result:
addrType = _afToType[family]
resolutionReceiver.addressResolved(
addrType(_socktypeToType.get(socktype, 'TCP'), *sockaddr)
)
resolutionReceiver.resolutionComplete()
return resolution
@implementer(IHostnameResolver)
class SimpleResolverComplexifier(object):
"""
A converter from L{IResolverSimple} to L{IHostnameResolver}.
"""
_log = Logger()
def __init__(self, simpleResolver):
"""
Construct a L{SimpleResolverComplexifier} with an L{IResolverSimple}.
"""
self._simpleResolver = simpleResolver
def resolveHostName(self, resolutionReceiver, hostName, portNumber=0,
addressTypes=None, transportSemantics='TCP'):
"""
See L{IHostnameResolver.resolveHostName}
@param resolutionReceiver: see interface
@param hostName: see interface
@param portNumber: see interface
@param addressTypes: see interface
@param transportSemantics: see interface
@return: see interface
"""
# If it's str, we need to make sure that it's just ASCII.
try:
hostName = hostName.encode('ascii')
except UnicodeEncodeError:
# If it's not just ASCII, IDNA it. We don't want to give a Unicode
# string with non-ASCII in it to Python 3, as if anyone passes that
# to a Python 3 stdlib function, it will probably use the wrong
# IDNA version and break absolutely everything
hostName = _idnaBytes(hostName)
# Make sure it's passed down as a native str, to maintain the interface
hostName = nativeString(hostName)
resolution = HostResolution(hostName)
resolutionReceiver.resolutionBegan(resolution)
onAddress = self._simpleResolver.getHostByName(hostName)
def addressReceived(address):
resolutionReceiver.addressResolved(IPv4Address('TCP', address,
portNumber))
def errorReceived(error):
if not error.check(DNSLookupError):
self._log.failure("while looking up {name} with {resolver}",
error, name=hostName,
resolver=self._simpleResolver)
onAddress.addCallbacks(addressReceived, errorReceived)
def finish(result):
resolutionReceiver.resolutionComplete()
onAddress.addCallback(finish)
return resolution
@implementer(IResolutionReceiver)
class FirstOneWins(object):
"""
An L{IResolutionReceiver} which fires a L{Deferred} with its first result.
"""
def __init__(self, deferred):
"""
@param deferred: The L{Deferred} to fire when the first resolution
result arrives.
"""
self._deferred = deferred
self._resolved = False
def resolutionBegan(self, resolution):
"""
See L{IResolutionReceiver.resolutionBegan}
@param resolution: See L{IResolutionReceiver.resolutionBegan}
"""
self._resolution = resolution
def addressResolved(self, address):
"""
See L{IResolutionReceiver.addressResolved}
@param address: See L{IResolutionReceiver.addressResolved}
"""
if self._resolved:
return
self._resolved = True
self._deferred.callback(address.host)
def resolutionComplete(self):
"""
See L{IResolutionReceiver.resolutionComplete}
"""
if self._resolved:
return
self._deferred.errback(DNSLookupError(self._resolution.name))
@implementer(IResolverSimple)
class ComplexResolverSimplifier(object):
"""
A converter from L{IHostnameResolver} to L{IResolverSimple}
"""
def __init__(self, nameResolver):
"""
Create a L{ComplexResolverSimplifier} with an L{IHostnameResolver}.
@param nameResolver: The L{IHostnameResolver} to use.
"""
self._nameResolver = nameResolver
def getHostByName(self, name, timeouts=()):
"""
See L{IResolverSimple.getHostByName}
@param name: see L{IResolverSimple.getHostByName}
@param timeouts: see L{IResolverSimple.getHostByName}
@return: see L{IResolverSimple.getHostByName}
"""
result = Deferred()
self._nameResolver.resolveHostName(FirstOneWins(result), name, 0,
[IPv4Address])
return result
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