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1 from twisted.application import service |
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2 from twisted.python import components, failure |
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3 from twisted.internet import defer, reactor |
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4 |
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5 class IBackendService(components.Interface): |
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6 """ Interface to a backend service of a pubsub service """ |
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7 |
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8 def do_publish(self, node, publisher, item): |
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9 """ Returns a deferred that returns """ |
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10 |
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11 class BackendException(Exception): |
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12 def __init__(self, msg = ''): |
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13 self.msg = msg |
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14 |
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15 def __str__(self): |
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16 return self.msg |
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17 |
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18 class NodeNotFound(BackendException): |
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19 #def __init__(self, msg = 'Node not found'): |
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20 # BackendException.__init__(self, msg) |
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21 pass |
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22 |
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23 class NotAuthorized(BackendException): |
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24 pass |
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25 |
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26 class MemoryBackendService(service.Service): |
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27 |
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28 __implements__ = IBackendService, |
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29 |
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30 def __init__(self): |
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31 self.nodes = {"ralphm/test": 'test'} |
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32 self.subscribers = {"ralphm/test": ["ralphm@ik.nu", "ralphm@doe.ik.nu"] } |
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33 self.affiliations = {"ralphm/test": { "ralphm@ik.nu": "owner", "ralphm@se-135.se.wtb.tue.nl": 'publisher', 'ralphm@doe.ik.nu': 'publisher' } } |
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34 |
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35 def do_publish(self, node, publisher, item): |
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36 try: |
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37 try: |
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38 result = self.nodes[node] |
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39 except KeyError: |
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40 raise NodeNotFound |
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41 |
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42 try: |
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43 affiliation = self.affiliations[node][publisher] |
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44 if affiliation not in ['owner', 'publisher']: |
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45 raise NotAuthorized |
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46 except KeyError: |
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47 raise NotAuthorized() |
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48 |
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49 print "publish by %s to %s" % (publisher, node) |
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50 |
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51 recipients = self.get_subscribers(node) |
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52 recipients.addCallback(self.magic_filter, node, item) |
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53 recipients.addCallback(self.pubsub_service.do_notification, node, item) |
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54 |
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55 return defer.succeed(result) |
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56 except: |
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57 f = failure.Failure() |
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58 return defer.fail(f) |
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59 |
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2
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60 def magic_filter(self, subscribers, node, item): |
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61 return subscribers |
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62 |
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63 def get_subscribers(self, node): |
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64 d = defer.Deferred() |
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65 try: |
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66 result = self.subscribers[node] |
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67 except: |
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68 f = failure.Failure() |
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69 reactor.callLater(0, d.errback, f) |
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70 else: |
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71 reactor.callLater(0, d.callback, result) |
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72 |
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73 return d |
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74 |
