win32_dns.py

import sys, os

from twisted.python.runtime import platform
from twisted.python import log
from twisted.names import root, resolve, cache, client
from twisted.internet import utils

def parseIpconfigDNSServers(output):
    servers = []
    found = False
    for line in output.split('\n'):
        if 'DNS Servers . . . . . . . . . . . :' in line or (found and not '. . . .' in line):
            servers.append(line[38:].strip())
            found = True
        else:
            found = False
    log.msg( 'Windows: Detected DNS servers %s' % (str(servers)))
    return servers

def patchWindowsDNS():
    if platform.getType() != 'posix':
        d = utils.getProcessOutput(os.path.join(os.environ['WINDIR'], 'system32', 'ipconfig.exe'), ["/all"])
        d.addCallback(parseIpconfigDNSServers)
        d.addCallback(lambda r: client.Resolver(servers=[(h, 53) for h in r]))
        d.addErrback(log.msg)
        theResolver = root.DeferredResolver(d)
        client.theResolver = resolve.ResolverChain([cache.CacheResolver(), theResolver])

if __name__ == '__main__':
    log.startLogging(sys.stdout)

    def do_lookup(domain):
        d = client.getHostByName(domain)
        d.addBoth(log.msg)

    patchWindowsDNS()

    from twisted.internet import reactor
    reactor.callLater(0, do_lookup, 'example.com')
    reactor.run()