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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,
AddressFamily,
SocketKind,
gaierror,
getaddrinfo,
)
from typing import (
TYPE_CHECKING,
Callable,
List,
NoReturn,
Optional,
Sequence,
Tuple,
Type,
Union,
)
from zope.interface import implementer
from twisted.internet.address import IPv4Address, IPv6Address
from twisted.internet.interfaces import (
IAddress,
IHostnameResolver,
IHostResolution,
IReactorThreads,
IResolutionReceiver,
)
from twisted.internet.threads import deferToThreadPool
if TYPE_CHECKING:
# The types below are copied from
# https://github.com/twisted/twisted/blob/release-21.2.0-10091/src/twisted/internet/interfaces.py
# so that the type hints can match the interfaces.
from twisted.python.runtime import platform
if platform.supportsThreads():
from twisted.python.threadpool import ThreadPool
else:
ThreadPool = object # type: ignore[misc, assignment]
@implementer(IHostResolution)
class HostResolution:
"""
The in-progress resolution of a given hostname.
"""
def __init__(self, name: str):
"""
Create a L{HostResolution} with the given name.
"""
self.name = name
def cancel(self) -> NoReturn:
# 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",
}
_GETADDRINFO_RESULT = List[
Tuple[
AddressFamily,
SocketKind,
int,
str,
Union[Tuple[str, int], Tuple[str, int, int, int]],
]
]
@implementer(IHostnameResolver)
class GAIResolver:
"""
L{IHostnameResolver} implementation that resolves hostnames by calling
L{getaddrinfo} in a thread.
"""
def __init__(
self,
reactor: IReactorThreads,
getThreadPool: Optional[Callable[[], "ThreadPool"]] = None,
getaddrinfo: Callable[[str, int, int, int], _GETADDRINFO_RESULT] = 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
# The types on IHostnameResolver is incorrect in Twisted, see
# https://twistedmatrix.com/trac/ticket/10276
def resolveHostName( # type: ignore[override]
self,
resolutionReceiver: IResolutionReceiver,
hostName: str,
portNumber: int = 0,
addressTypes: Optional[Sequence[Type[IAddress]]] = None,
transportSemantics: str = "TCP",
) -> IHostResolution:
"""
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() -> _GETADDRINFO_RESULT:
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: _GETADDRINFO_RESULT) -> None:
for family, socktype, _proto, _cannoname, sockaddr in result:
addrType = _afToType[family]
resolutionReceiver.addressResolved(
addrType(_socktypeToType.get(socktype, "TCP"), *sockaddr)
)
resolutionReceiver.resolutionComplete()
return resolution
|
