Added option for iq.send to accept a callhandler.

The callback will be a stream level handler, and will not
execute in its own thread. If you must have a thread, have the
callback function raise a custom event, which can be processed
by another event handler, which may run in an individual thread,
like so:

def handle_reply(self, iq):
    self.event('custom_event', iq)

def do_long_operation_in_thread(self, iq):
    ...

self.add_event_handler('custom_event', self.do_long_operation_in_thread)

...take out already prepared iq stanza...
iq.send(callback=self.handle_reply)

sleekxmpp/stanza/iq.py

@@ -9,7 +9,7 @@
 from sleekxmpp.stanza import Error
 from sleekxmpp.stanza.rootstanza import RootStanza
 from sleekxmpp.xmlstream import StanzaBase, ET
-from sleekxmpp.xmlstream.handler import Waiter
+from sleekxmpp.xmlstream.handler import Waiter, Callback
 from sleekxmpp.xmlstream.matcher import MatcherId
 
 
@@ -157,13 +157,19 @@ class Iq(RootStanza):
         StanzaBase.reply(self)
         return self
 
-    def send(self, block=True, timeout=None):
+    def send(self, block=True, timeout=None, callback=None):
         """
         Send an <iq> stanza over the XML stream.
 
         The send call can optionally block until a response is received or
         a timeout occurs. Be aware that using blocking in non-threaded event
-        handlers can drastically impact performance.
+        handlers can drastically impact performance. Otherwise, a callback
+        handler can be provided that will be executed when the Iq stanza's
+        result reply is received. Be aware though that that the callback
+        handler will not be executed in its own thread.
+
+        Using both block and callback is not recommended, and only the
+        callback argument will be used in that case.
 
         Overrides StanzaBase.send
 
@@ -173,12 +179,21 @@ class Iq(RootStanza):
             timeout  -- The length of time (in seconds) to wait for a response
                         before exiting the send call if blocking is used.
                         Defaults to sleekxmpp.xmlstream.RESPONSE_TIMEOUT
+            callback -- Optional reference to a stream handler function. Will
+                        be executed when a reply stanza is received.
         """
         if timeout is None:
             timeout = self.stream.response_timeout
-        if block and self['type'] in ('get', 'set'):
+        if callback is not None and self['type'] in ('get', 'set'):
+            handler = Callback('IqCallback_%s' % self['id'],
+                               MatcherId(self['id']),
+                               callback,
+                               once=True)
+            self.stream.register_handler(handler)
+            return None
+        elif block and self['type'] in ('get', 'set'):
             waitfor = Waiter('IqWait_%s' % self['id'], MatcherId(self['id']))
-            self.stream.registerHandler(waitfor)
+            self.stream.register_handler(waitfor)
             StanzaBase.send(self)
             return waitfor.wait(timeout)
         else:

sleekxmpp/test/sleektest.py

@@ -52,6 +52,10 @@ class SleekTest(unittest.TestCase):
         compare              -- Compare XML objects against each other.
     """
 
+    def __init__(self, *args, **kwargs):
+        unittest.TestCase.__init__(self, *args, **kwargs)
+        self.xmpp = None
+
     def runTest(self):
         pass
 
@@ -86,7 +90,7 @@ class SleekTest(unittest.TestCase):
         Arguments:
             xml -- An XML object to use for the Message's values.
         """
-        return Message(None, *args, **kwargs)
+        return Message(self.xmpp, *args, **kwargs)
 
     def Iq(self, *args, **kwargs):
         """
@@ -97,7 +101,7 @@ class SleekTest(unittest.TestCase):
         Arguments:
             xml -- An XML object to use for the Iq's values.
         """
-        return Iq(None, *args, **kwargs)
+        return Iq(self.xmpp, *args, **kwargs)
 
     def Presence(self, *args, **kwargs):
         """
@@ -108,7 +112,7 @@ class SleekTest(unittest.TestCase):
         Arguments:
             xml -- An XML object to use for the Iq's values.
         """
-        return Presence(None, *args, **kwargs)
+        return Presence(self.xmpp, *args, **kwargs)
 
     def check_jid(self, jid, user=None, domain=None, resource=None,
                   bare=None, full=None, string=None):

tests/test_stream_handlers.py

@@ -1,3 +1,5 @@
+import time
+
 from sleekxmpp.test import *
 from sleekxmpp.xmlstream.handler import *
 from sleekxmpp.xmlstream.matcher import *
@@ -108,5 +110,41 @@ class TestHandlers(SleekTest):
         self.failUnless(waiter_exists == False,
             "Waiter handler was not removed.")
 
+    def testIqCallback(self):
+        """Test that iq.send(callback=handle_foo) works."""
+        events = []
+
+        def handle_foo(iq):
+            events.append('foo')
+
+        iq = self.Iq()
+        iq['type'] = 'get'
+        iq['id'] = 'test-foo'
+        iq['to'] = 'user@localhost'
+        iq['query'] = 'foo'
+        iq.send(callback=handle_foo)
+
+        self.send("""
+          <iq type="get" id="test-foo" to="user@localhost">
+            <query xmlns="foo" />
+          </iq>
+        """)
+
+        self.recv("""
+          <iq type="result" id="test-foo"
+              to="test@localhost"
+              from="user@localhost">
+            <query xmlns="foo">
+              <data />
+            </query>
+          </iq>
+        """)
+
+        # Give event queue time to process
+        time.sleep(0.1)
+
+        self.failUnless(events == ['foo'],
+                "Iq callback was not executed: %s" % events)
+
 
 suite = unittest.TestLoader().loadTestsFromTestCase(TestHandlers)