scrapy/tests/mockserver/dns.py

67 lines
1.7 KiB
Python

from __future__ import annotations
import sys
from subprocess import PIPE, Popen
from twisted.internet import defer
from twisted.names import dns, error
from twisted.names.server import DNSServerFactory
from tests.utils import get_script_run_env
class MockDNSResolver:
"""
Implements twisted.internet.interfaces.IResolver partially
"""
def _resolve(self, name):
record = dns.Record_A(address=b"127.0.0.1")
answer = dns.RRHeader(name=name, payload=record)
return [answer], [], []
def query(self, query, timeout=None):
if query.type == dns.A:
return defer.succeed(self._resolve(query.name.name))
return defer.fail(error.DomainError())
def lookupAllRecords(self, name, timeout=None):
return defer.succeed(self._resolve(name))
class MockDNSServer:
def __enter__(self):
self.proc = Popen(
[sys.executable, "-u", "-m", "tests.mockserver.dns"],
stdout=PIPE,
env=get_script_run_env(),
text=True,
)
self.host = "127.0.0.1"
self.port = int(self.proc.stdout.readline().strip().split(":")[1])
return self
def __exit__(self, exc_type, exc_value, traceback):
self.proc.kill()
self.proc.communicate()
def main() -> None:
from twisted.internet import reactor
clients = [MockDNSResolver()]
factory = DNSServerFactory(clients=clients)
protocol = dns.DNSDatagramProtocol(controller=factory)
listener = reactor.listenUDP(0, protocol)
def print_listening():
host = listener.getHost()
print(f"{host.host}:{host.port}")
reactor.callWhenRunning(print_listening)
reactor.run()
if __name__ == "__main__":
main()