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comparison idavoll/backend.py @ 29:d4fc29bb5381

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Define interfaces of blocks of functionality.
author Ralph Meijer <ralphm@ik.nu>
date Tue, 26 Oct 2004 16:25:59 +0000
parents 4f3bbefc6fad
children b65b7ea5c992
comparison
equal deleted inserted replaced
28:39d0c6fa027f 29:d4fc29bb5381
1 from twisted.python import components 1 from twisted.python import components
2 2 from twisted.application import service
3 class IService(components.Interface): 3 from twisted.xish import utility
4 """ Interface to a backend service of a pubsub service """
5
6 def do_publish(self, node, publisher, item):
7 """ Returns a deferred that returns """
8 4
9 class Error(Exception): 5 class Error(Exception):
10 msg = '' 6 msg = ''
11 7
12 def __str__(self): 8 def __str__(self):
13 return self.msg 9 return self.msg
14 10
15 class NodeNotFound(Error): 11 class NodeNotFound(Error):
16 msg = 'Node not found' 12 msg = 'Node not found'
17 13
18 class NotAuthorized(Error): 14 class NotAuthorized(Error):
19 pass 15 pass
20 16
21 class PayloadExpected(Error): 17 class PayloadExpected(Error):
22 msg = 'Payload expected' 18 msg = 'Payload expected'
23 19
24 class NoPayloadAllowed(Error): 20 class NoPayloadAllowed(Error):
25 msg = 'No payload allowed' 21 msg = 'No payload allowed'
26 22
27 class NoInstantNodes(Error): 23 class NoInstantNodes(Error):
28 pass 24 pass
29 25
30 class NodeExists(Error): 26 class NodeExists(Error):
31 pass 27 pass
28
29 class NotImplemented(Error):
30 msg = 'Oops!'
31
32 class IBackendService(components.Interface):
33 """ Interface to a backend service of a pubsub service. """
34
35 def get_supported_affiliations(self):
36 """ Reports the list of supported affiliation types.
37
38 @return: a list of supported affiliation types.
39 """
40
41 class INodeCreationService(components.Interface):
42 """ A service for creating nodes """
43
44 def create_node(self, node_id, requestor):
45 """ Create a node.
46
47 @return: a deferred that fires when the node has been created.
48 """
49
50 class IPublishService(components.Interface):
51 """ A service for publishing items to a node. """
52
53 def publish(self, node_id, items, requestor):
54 """ Publish items to a pubsub node.
55
56 @return: a deferred that fires when the items have been published.
57 """
58 class INotificationService(components.Interface):
59 """ A service for notification of published items. """
60
61 def register_notifier(self, observerfn, *args, **kwargs):
62 """ Register callback which is called for notification. """
63
64 def get_notification_list(self, node_id, items):
65 pass
66
67 class ISubscriptionService(components.Interface):
68 """ A service for managing subscriptions. """
69
70 def subscribe(self, node_id, subscriber, requestor):
71 """ Request the subscription of an entity to a pubsub node.
72
73 Depending on the node's configuration and possible business rules, the
74 C{subscriber} is added to the list of subscriptions of the node with id
75 C{node_id}. The C{subscriber} might be different from the C{requestor},
76 and if the C{requestor} is not allowed to subscribe this entity an
77 exception should be raised.
78
79 @return: a deferred that returns the subscription state
80 """
81
82 def unsubscribe(self, node_id, subscriber, requestor):
83 """ Cancel the subscription of an entity to a pubsub node.
84
85 The subscription of C{subscriber} is removed from the list of
86 subscriptions of the node with id C{node_id}. If the C{requestor}
87 is not allowed to unsubscribe C{subscriber}, an an exception should
88 be raised.
89
90 @return: a deferred that fires when unsubscription is complete.
91 """
92
93 class IAffiliationsService(components.Interface):
94 """ A service for retrieving the affiliations with this pubsub service. """
95
96 def get_affiliations(self, entity):
97 """ Report the list of current affiliations with this pubsub service.
98
99 Report the list of the current affiliations with all nodes within this
100 pubsub service, along with subscriptions to such nodes, for the
101 C{entity}.
102
103 @return: a deferred that returns the list of all current affiliations
104 and subscriptions.
105 """
106
107 class IPersistenceService(components.Interface):
108 """ A service for persisting published items """
109
110 def store_items(self, node_id, items, publisher):
111 """ Store items for a node, recording the publisher """
112
113 class IRetractionService(components.Interface):
114 """ A service for retracting published items """
115
116 def retract_item(self, node_id, item_id, requestor):
117 """ Removes item in node from persistent storage """
118
119 def purge_node(self, node_id, requestor):
120 """ Removes all items in node from persistent storage """
121
122 class IItemRetrievalService(components.Interface):
123 """ A service for retrieving previously published items. """
124
125 def get_items(self, node_id, max_items=None, item_ids=[],
126 requestor=None):
127 """ Retrieve items from persistent storage
128
129 If C{max_items} is given, return the C{max_items} last published
130 items, else if C{item_ids} is not empty, return the items requested.
131 If neither is given, return all items.
132
133 @return: a deferred that returns the requested items
134 """
135
136 class BackendService(service.MultiService, utility.EventDispatcher):
137
138 __implements__ = IBackendService,
139
140 def __init__(self):
141 service.MultiService.__init__(self)
142 utility.EventDispatcher.__init__(self)
143
144 class NotificationService(service.Service):
145
146 def register_notifier(self, observerfn, *args, **kwargs):
147 self.parent.addObserver('//event/pubsub/notify', observerfn,
148 *args, **kwargs)