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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 socket import (
AF_INET,
AF_INET6,
AF_UNSPEC,
SOCK_DGRAM,
SOCK_STREAM,
gaierror,
getaddrinfo,
)
from zope.interface import implementer
from twisted.internet._idna import _idnaBytes
from twisted.internet.address import IPv4Address, IPv6Address
from twisted.internet.defer import Deferred
from twisted.internet.error import DNSLookupError
from twisted.internet.interfaces import (
IHostnameResolver,
IHostResolution,
IResolutionReceiver,
IResolverSimple,
)
from twisted.internet.threads import deferToThreadPool
from twisted.logger import Logger
from twisted.python.compat import nativeString
@implementer(IHostResolution)
class HostResolution:
"""
The in-progress resolution of a given hostname.
"""
def __init__(self, name):
"""
Create a L{HostResolution} with the given name.
"""
self.name = name
def cancel(self):
# IHostResolution.cancel
raise NotImplementedError()
_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:
"""
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:
"""
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:
"""
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:
"""
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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