core: added "one_shot" option to registered callback:

when this keyword is used, the callback is automatically removed once it has been called.

src/core/sat_main.py

@@ -847,6 +847,7 @@ class SAT(service.Service):
         """ Register a callback.
         Use with_data=True in kwargs if the callback use the optional data dict
         use force_id=id to avoid generated id. Can lead to name conflict, avoid if possible
+        use one_shot=True to delete callback once it have been called
         @param callback: any callable
         @return: id of the registered callback
         """
@@ -857,11 +858,21 @@ class SAT(service.Service):
             if callback_id in self._cb_map:
                 raise exceptions.ConflictError(_(u"id already registered"))
         self._cb_map[callback_id] = (callback, args, kwargs)
+
+        if "one_shot" in kwargs: # One Shot callback are removed after 30 min
+            def purgeCallback():
+                try:
+                    self.removeCallback(callback_id)
+                except KeyError:
+                    pass
+            reactor.callLater(1800, purgeCallback)
+
         return callback_id
 
     def removeCallback(self, callback_id):
         """ Remove a previously registered callback
         @param callback_id: id returned by [registerCallback] """
+        debug("Removing callback [%s]" % callback_id)
         del self._cb_map[callback_id]
 
     def launchCallback(self, callback_id, data=None, profile_key="@NONE@"):
@@ -889,6 +900,9 @@ class SAT(service.Service):
             kwargs["profile"] = profile
             del kwargs["with_data"]
 
+        if kwargs.pop('one_shot', False):
+            self.removeCallback(callback_id)
+
         return defer.maybeDeferred(callback, *args, **kwargs)
 
     #Menus management