# Twisted, the Framework of Your Internet
# Copyright (C) 2001 Matthew W. Lefkowitz
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of version 2.1 of the GNU Lesser General Public
# License as published by the Free Software Foundation.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
from twisted.protocols import dns
from twisted.python import failure
from twisted.internet import interfaces,defer
def searchFileFor(file, name):
try:
fp = open(file)
except:
return None
lines = fp.readlines()
for line in lines:
idx = line.find('#')
if idx != -1:
line = line[:idx]
if not line:
continue
parts = line.split()
if name.lower() in [s.lower() for s in parts[1:]]:
return parts[0]
return None
class Resolver:
"""A resolver that services hosts(5) format files."""
__implements__ = (interfaces.IResolverSimple,)
def __init__(self, file='/etc/hosts', ttl = 60 * 60):
self.file = file
self.ttl = ttl
def query(self, query, timeout = 10):
return self._lookup(str(query.name), query.type, query.type, timeout)
def _lookup(self, name, cls, type, timeout):
if cls != dns.IN or type != dns.A:
return defer.fail(failure.Failure(NotImplementedError(type, cls)))
return self.lookupAddress(
name, timeout
)
def lookupAddress(self, name, timeout=10):
res = searchFileFor(self.file, name)
if res:
return defer.succeed([
dns.RRHeader(name, dns.A, dns.IN, self.ttl)
])
return defer.fail(failure.Failure(dns.DomainError(name)))
lookupAllRecords = lookupAddress
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