Add better DNS resolver wrapper.

1 files changed, 27 insertions, 97 deletions

diff --git a/sleekxmpp/xmlstream/xmlstream.py b/sleekxmpp/xmlstream/xmlstream.py
index 45f27929..31ca9cfe 100644
--- a/sleekxmpp/xmlstream/xmlstream.py
+++ b/sleekxmpp/xmlstream/xmlstream.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
     sleekxmpp.xmlstream.xmlstream
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -39,19 +38,13 @@ from sleekxmpp.xmlstream import Scheduler, tostring
 from sleekxmpp.xmlstream.stanzabase import StanzaBase, ET, ElementBase
 from sleekxmpp.xmlstream.handler import Waiter, XMLCallback
 from sleekxmpp.xmlstream.matcher import MatchXMLMask
+from sleekxmpp.xmlstream.resolver import resolve, default_resolver
 
 # In Python 2.x, file socket objects are broken. A patched socket
 # wrapper is provided for this case in filesocket.py.
 if sys.version_info < (3, 0):
     from sleekxmpp.xmlstream.filesocket import FileSocket, Socket26
 
-try:
-    import dns.resolver
-except ImportError:
-    DNSPYTHON = False
-else:
-    DNSPYTHON = True
-
 
 #: The time in seconds to wait before timing out waiting for response stanzas.
 RESPONSE_TIMEOUT = 30
@@ -306,6 +299,11 @@ class XMLStream(object):
         #: A list of DNS results that have not yet been tried.
         self.dns_answers = []
 
+        #: The service name to check with DNS SRV records. For
+        #: example, setting this to ``'xmpp-client'`` would query the
+        #: ``_xmpp-client._tcp`` service.
+        self.dns_service = None
+
         self.add_event_handler('connected', self._handle_connected)
         self.add_event_handler('session_start', self._start_keepalive)
         self.add_event_handler('disconnected', self._end_keepalive)
@@ -445,25 +443,10 @@ class XMLStream(object):
                 self.stop.set()
                 return False
 
-        try:
-            # Look for IPv6 addresses, in addition to IPv4
-            for res in Socket.getaddrinfo(self.address[0],
-                                          int(self.address[1]),
-                                          0,
-                                          Socket.SOCK_STREAM):
-                log.debug("Trying: %s", res[-1])
-                af, sock_type, proto, canonical, sock_addr = res
-                try:
-                    self.socket = self.socket_class(af, sock_type, proto)
-                    break
-                except Socket.error:
-                    log.debug("Could not open IPv%s socket." % proto)
-        except Socket.gaierror:
-            log.warning("Socket could not be opened: no connectivity" + \
-                        " or wrong IP versions.")
-            if reattempt:
-                self.reconnect_delay = delay
-            return False
+        af = Socket.AF_INET
+        if ':' in self.address[0]:
+            af = Socket.AF_INET6
+        self.socket = self.socket_class(af, Socket.SOCK_STREAM)
 
         self.configure_socket()
 
@@ -511,7 +494,10 @@ class XMLStream(object):
         except Socket.error as serr:
             error_msg = "Could not connect to %s:%s. Socket Error #%s: %s"
             self.event('socket_error', serr, direct=True)
-            log.error(error_msg, self.address[0], self.address[1],
+            domain = self.address[0]
+            if ':' in domain:
+                domain = '[%s]' % domain
+            log.error(error_msg, domain, self.address[1],
                                  serr.errno, serr.strerror)
             if reattempt:
                 self.reconnect_delay = delay
@@ -915,50 +901,11 @@ class XMLStream(object):
         """
         if port is None:
             port = self.default_port
-        if DNSPYTHON:
-            resolver = dns.resolver.get_default_resolver()
-            self.configure_dns(resolver, domain=domain, port=port)
-
-            v4_answers = []
-            v6_answers = []
-            answers = []
-
-            try:
-                log.debug("Querying A records for %s" % domain)
-                v4_answers = resolver.query(domain, dns.rdatatype.A)
-            except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
-                log.warning("No A records for %s", domain)
-                v4_answers = [((domain, port), 0, 0)]
-            except dns.exception.Timeout:
-                log.warning("DNS resolution timed out " + \
-                            "for A record of %s", domain)
-                v4_answers = [((domain, port), 0, 0)]
-            else:
-                for ans in v4_answers:
-                    log.debug("Found A record: %s", ans.address)
-                    answers.append(((ans.address, port), 0, 0))
-
-            try:
-                log.debug("Querying AAAA records for %s" % domain)
-                v6_answers = resolver.query(domain, dns.rdatatype.AAAA)
-            except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
-                log.warning("No AAAA records for %s", domain)
-                v6_answers = [((domain, port), 0, 0)]
-            except dns.exception.Timeout:
-                log.warning("DNS resolution timed out " + \
-                            "for AAAA record of %s", domain)
-                v6_answers = [((domain, port), 0, 0)]
-            else:
-                for ans in v6_answers:
-                    log.debug("Found AAAA record: %s", ans.address)
-                    answers.append(((ans.address, port), 0, 0))
+            
+        resolver = default_resolver()
+        self.configure_dns(resolver, domain=domain, port=port)
 
-            return answers
-        else:
-            log.warning("dnspython is not installed -- " + \
-                        "relying on OS A/AAAA record resolution")
-            self.configure_dns(None, domain=domain, port=port)
-            return [((domain, port), 0, 0)]
+        return resolve(domain, port, service=self.dns_service, resolver=resolver)
 
     def pick_dns_answer(self, domain, port=None):
         """Pick a server and port from DNS answers.
@@ -971,33 +918,16 @@ class XMLStream(object):
         """
         if not self.dns_answers:
             self.dns_answers = self.get_dns_records(domain, port)
-        addresses = {}
-        intmax = 0
-        topprio = 65535
-        for answer in self.dns_answers:
-            topprio = min(topprio, answer[1])
-        for answer in self.dns_answers:
-            if answer[1] == topprio:
-                intmax += answer[2]
-                addresses[intmax] = answer[0]
-
-        #python3 returns a generator for dictionary keys
-        items = [x for x in addresses.keys()]
-        items.sort()
-
-        address = (domain, port)
-        picked = random.randint(0, intmax)
-        for item in items:
-            if picked <= item:
-                address = addresses[item]
-                break
-        for idx, answer in enumerate(self.dns_answers):
-            if self.dns_answers[0] == address:
-                self.dns_answers.pop(idx)
-                break
-        log.debug("Trying to connect to %s:%s", *address)
-        return address
 
+        try:
+            if sys.version_info < (3, 0):
+                return self.dns_answers.next()
+            else:
+                return next(self.dns_answers)
+        except StopIteration:
+            self.dns_answers = None
+            return (domain, port)
+            
     def add_event_handler(self, name, pointer,
                           threaded=False, disposable=False):
         """Add a custom event handler that will be executed whenever