clients now take and methods:

 is if you are using  and want to be notified if an error occurs, otherwise
it will be consumed by the thread
 is the new way to express that you wish the function to be executed asynchornously, in
a thread. this can be advantageous in web request loops where  you want to return as quickly as possible,

additionally, samuraisam#25 is addressed, providing a wrapper for notify/feedback which will automatically
try to re-provision the endpoint if it reports UnknownAppID at some point, (this can happen if there
is a pyapns server restart or something)

pyapns/client.py

@@ -1,6 +1,7 @@
 import xmlrpclib
 import threading
 import httplib
+import functools
 from sys import hexversion
 
 OPTIONS = {'CONFIGURED': False, 'TIMEOUT': 20}
@@ -40,32 +41,76 @@ def configure(opts):
 class UnknownAppID(Exception): pass
 class APNSNotConfigured(Exception): pass
 
+def reprovision_and_retry(func):
+  """
+  Wraps the `errback` callback of the API functions, automatically trying to
+  re-provision if the app ID can not be found during the operation. If that's
+  unsuccessful, it will raise the UnknownAppID error.
+  """
+  @functools.wraps(func)
+  def wrapper(*a, **kw):
+    errback = kw.get('errback', None)
+    if errback is None:
+      def errback(e):
+        raise e
+    def errback_wrapper(e):
+      if isinstance(e, UnknownAppID) and 'INITIAL' in OPTIONS:
+        try:
+          for initial in OPTIONS['INITIAL']:
+            provision(*initial) # retry provisioning the initial setup
+          func(*a, **kw) # and try the function once more
+        except Exception, new_exc:
+          errback(new_exc) # throwing the new exception
+      else:
+        errback(e) # not an instance of UnknownAppID - nothing we can do here
+    kw['errback'] = errback_wrapper
+    return func(*a, **kw)
+  return wrapper
+
+def default_callback(func):
+  @functools.wraps(func)
+  def wrapper(*a, **kw):
+    if 'callback' not in kw:
+      kw['callback'] = lambda c: c
+    return func(*a, **kw)
+  return wrapper
 
-def provision(app_id, path_to_cert, environment, timeout=15, callback=None):
+@default_callback
+@reprovision_and_retry
+def provision(app_id, path_to_cert, environment, timeout=15, async=False, 
+              callback=None, errback=None):
   args = [app_id, path_to_cert, environment, timeout]
-  if callback is None:
-    return _xmlrpc_thread('provision', args, lambda r: r)
-  t = threading.Thread(target=_xmlrpc_thread, args=['provision', args, callback])
+  f_args = ['provision', args, callback, errback]
+  if not async:
+    return _xmlrpc_thread(*f_args)
+  t = threading.Thread(target=_xmlrpc_thread, args=f_args)
   t.daemon = True
   t.start()
 
-def notify(app_id, tokens, notifications, callback=None):
+@default_callback
+@reprovision_and_retry
+def notify(app_id, tokens, notifications, async=False, callback=None, 
+           errback=None):
   args = [app_id, tokens, notifications]
-  if callback is None:
-    return _xmlrpc_thread('notify', args, lambda r: r)
-  t = threading.Thread(target=_xmlrpc_thread, args=['notify', args, callback])
+  f_args = ['notify', args, callback, errback]
+  if not async:
+    return _xmlrpc_thread(*f_args)
+  t = threading.Thread(target=_xmlrpc_thread, args=f_args)
   t.daemon = True
   t.start()
 
-def feedback(app_id, callback=None):
+@default_callback
+@reprovision_and_retry
+def feedback(app_id, async=False, callback=None, errback=None):
   args = [app_id]
-  if callback is None:
-    return _xmlrpc_thread('feedback', args, lambda r: r)
-  t = threading.Thread(target=_xmlrpc_thread, args=['feedback', args, callback])
+  f_args = ['feedback', args, callback, errback]
+  if not async:
+    return _xmlrpc_thread(*f_args)
+  t = threading.Thread(target=_xmlrpc_thread, args=f_args)
   t.daemon = True
   t.start()
 
-def _xmlrpc_thread(method, args, callback):
+def _xmlrpc_thread(method, args, callback, errback=None):
   if not configure({}):
     raise APNSNotConfigured('APNS Has not been configured.')
   proxy = ServerProxy(OPTIONS['HOST'], allow_none=True, use_datetime=True,
@@ -77,8 +122,11 @@ def _xmlrpc_thread(method, args, callback):
     return callback(proxy(*args))
   except xmlrpclib.Fault, e:
     if e.faultCode == 404:
-      raise UnknownAppID
-    raise
+      e = UnknownAppID()
+    if errback is not None:
+      errback(e)
+    else:
+      raise e
 
 
 ## --------------------------------------------------------------