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# This is a direct lift from
# https://github.com/twisted/twisted/blob/release-21.2.0-10091/src/twisted/internet/_resolver.py.
# We copy it here as we need to instantiate `GAIResolver` manually, but it is a
# private class.
from socket import (
AF_INET,
AF_INET6,
AF_UNSPEC,
SOCK_DGRAM,
SOCK_STREAM,
gaierror,
getaddrinfo,
)
from zope.interface import implementer
from twisted.internet.address import IPv4Address, IPv6Address
from twisted.internet.interfaces import IHostnameResolver, IHostResolution
from twisted.internet.threads import deferToThreadPool
@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
|
