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# Copyright (C) 2020 Philipp Hörist <philipp AT hoerist.com>
#
# This file is part of nbxmpp.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 3
# of the License, or (at your option) any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; If not, see <http://www.gnu.org/licenses/>.
import logging
from gi.repository import Gio
from gi.repository import GLib
log = logging.getLogger('nbxmpp.resolver')
class DNSResolveRequest:
def __init__(self, cache, domain, callback):
self._domain = domain
self._result = self._lookup_cache(cache)
self._callback = callback
@property
def result(self):
return self._result
@result.setter
def result(self, value):
self._result = value
@property
def is_cached(self):
return self.result is not None
def _lookup_cache(self, cache):
cached_request = cache.get(self)
if cached_request is None:
return None
return cached_request.result
def finalize(self):
GLib.idle_add(self._callback, self.result)
self._callback = None
def __hash__(self):
raise NotImplementedError
def __eq__(self, other):
return hash(other) == hash(self)
class AlternativeMethods(DNSResolveRequest):
def __init__(self, *args, **kwargs):
DNSResolveRequest.__init__(self, *args, **kwargs)
@property
def hostname(self):
return '_xmppconnect.%s' % self._domain
def __hash__(self):
return hash(self.hostname)
class Singleton(type):
_instances = {}
def __call__(cls, *args, **kwargs):
if cls not in cls._instances:
cls._instances[cls] = super(Singleton, cls).__call__(*args,
**kwargs)
return cls._instances[cls]
class GioResolver(metaclass=Singleton):
def __init__(self):
self._cache = {}
def _cache_request(self, request):
self._cache[request] = request
def resolve_alternatives(self, domain, callback):
request = AlternativeMethods(self._cache, domain, callback)
if request.is_cached:
request.finalize()
return
Gio.Resolver.get_default().lookup_records_async(
request.hostname,
Gio.ResolverRecordType.TXT,
None,
self._on_alternatives_result,
request)
def _on_alternatives_result(self, resolver, result, request):
try:
results = resolver.lookup_records_finish(result)
except GLib.Error as error:
log.info(error)
request.finalize()
return
try:
websocket_uri = self._parse_alternative_methods(results)
except Exception:
log.exception('Failed to parse alternative '
'connection methods: %s', results)
request.finalize()
return
request.result = websocket_uri
self._cache_request(request)
request.finalize()
@staticmethod
def _parse_alternative_methods(variant_results):
result_list = [res[0][0] for res in variant_results]
for result in result_list:
if result.startswith('_xmpp-client-websocket'):
return result.split('=')[1]
return None
if __name__ == '__main__':
import sys
try:
domain_ = sys.argv[1]
except Exception:
print('Provide domain name as argument')
sys.exit()
# Execute:
# > python3 -m nbxmpp.resolver domain
def on_result(result):
print('Result: ', result)
mainloop.quit()
GioResolver().resolve_alternatives(domain_, on_result)
mainloop = GLib.MainLoop()
mainloop.run()
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