--- a/idavoll/backend.py	Mon Oct 18 15:29:25 2004 +0000
+++ b/idavoll/backend.py	Tue Oct 26 16:25:59 2004 +0000
@@ -1,31 +1,148 @@
 from twisted.python import components
-
-class IService(components.Interface):
-	""" Interface to a backend service of a pubsub service """
-
-	def do_publish(self, node, publisher, item):
-		""" Returns a deferred that returns """
+from twisted.application import service
+from twisted.xish import utility
 
 class Error(Exception):
-	msg = ''
+    msg = ''
 
-	def __str__(self):
-		return self.msg
-	
+    def __str__(self):
+        return self.msg
+    
 class NodeNotFound(Error):
-	msg = 'Node not found'
+    msg = 'Node not found'
 
 class NotAuthorized(Error):
-	pass
+    pass
 
 class PayloadExpected(Error):
-	msg = 'Payload expected'
+    msg = 'Payload expected'
 
 class NoPayloadAllowed(Error):
-	msg = 'No payload allowed'
+    msg = 'No payload allowed'
 
 class NoInstantNodes(Error):
-	pass
+    pass
 
 class NodeExists(Error):
-	pass
+    pass
+
+class NotImplemented(Error):
+    msg = 'Oops!'
+
+class IBackendService(components.Interface):
+    """ Interface to a backend service of a pubsub service. """
+
+    def get_supported_affiliations(self):
+        """ Reports the list of supported affiliation types.
+    
+        @return: a list of supported affiliation types.
+        """
+
+class INodeCreationService(components.Interface):
+    """ A service for creating nodes """
+
+    def create_node(self, node_id, requestor):
+        """ Create a node.
+        
+        @return: a deferred that fires when the node has been created.
+        """
+
+class IPublishService(components.Interface):
+    """ A service for publishing items to a node. """
+
+    def publish(self, node_id, items, requestor):
+        """ Publish items to a pubsub node.
+        
+        @return: a deferred that fires when the items have been published.
+        """
+class INotificationService(components.Interface):
+    """ A service for notification of published items. """
+
+    def register_notifier(self, observerfn, *args, **kwargs):
+        """ Register callback which is called for notification. """
+
+    def get_notification_list(self, node_id, items):
+        pass
+
+class ISubscriptionService(components.Interface):
+    """ A service for managing subscriptions. """
+
+    def subscribe(self, node_id, subscriber, requestor):
+        """ Request the subscription of an entity to a pubsub node.
+
+        Depending on the node's configuration and possible business rules, the
+        C{subscriber} is added to the list of subscriptions of the node with id
+        C{node_id}. The C{subscriber} might be different from the C{requestor},
+        and if the C{requestor} is not allowed to subscribe this entity an
+        exception should be raised.
+    
+        @return: a deferred that returns the subscription state
+        """
+
+    def unsubscribe(self, node_id, subscriber, requestor):
+        """ Cancel the subscription of an entity to a pubsub node.
+
+        The subscription of C{subscriber} is removed from the list of
+        subscriptions of the node with id C{node_id}. If the C{requestor}
+        is not allowed to unsubscribe C{subscriber}, an an exception should
+        be raised.
+
+        @return: a deferred that fires when unsubscription is complete.
+        """
+
+class IAffiliationsService(components.Interface):
+    """ A service for retrieving the affiliations with this pubsub service. """
+
+    def get_affiliations(self, entity):
+        """ Report the list of current affiliations with this pubsub service.
+
+        Report the list of the current affiliations with all nodes within this
+        pubsub service, along with subscriptions to such nodes, for the
+        C{entity}.
+
+        @return: a deferred that returns the list of all current affiliations
+        and subscriptions.
+        """
+
+class IPersistenceService(components.Interface):
+    """ A service for persisting published items """
+
+    def store_items(self, node_id, items, publisher):
+        """ Store items for a node, recording the publisher """
+
+class IRetractionService(components.Interface):
+    """ A service for retracting published items """
+
+    def retract_item(self, node_id, item_id, requestor):
+        """ Removes item in node from persistent storage """
+
+    def purge_node(self, node_id, requestor):
+        """ Removes all items in node from persistent storage """
+
+class IItemRetrievalService(components.Interface):
+    """ A service for retrieving previously published items. """
+
+    def get_items(self, node_id, max_items=None, item_ids=[],
+                  requestor=None):
+        """ Retrieve items from persistent storage
+
+        If C{max_items} is given, return the C{max_items} last published
+        items, else if C{item_ids} is not empty, return the items requested.
+        If neither is given, return all items.
+
+        @return: a deferred that returns the requested items
+        """
+
+class BackendService(service.MultiService, utility.EventDispatcher):
+
+    __implements__ = IBackendService,
+
+    def __init__(self):
+        service.MultiService.__init__(self)
+        utility.EventDispatcher.__init__(self)
+
+class NotificationService(service.Service):
+
+    def register_notifier(self, observerfn, *args, **kwargs):
+        self.parent.addObserver('//event/pubsub/notify', observerfn,
+                                *args, **kwargs)