Source Code for Module sparked.internet.zeroconf

  1  # Copyright (c) 2010 Arjan Scherpenisse 
  2  # See LICENSE for details. 
  3   
  4  """ 
  5  A mixin object for Service instances that announce the service over Zeroconf. 
  6  """ 
  7   
  8  import avahi 
  9  import dbus 
 10   
 11  from twisted.python import log 
 12  from sparked import events 
 13   
 14   
 15 -class _ZeroconfService (object): 
 16      """ 
 17      A globally defined object which interfaces with avahi. 
 18      """ 
 19   
 20 -    def __init__(self): 
 21          self.published = {} 
 22          self.server = None 
 23          self.bus = None 
 24          self.subscribed = [] 
 25   
 26   
 27 -    def publishService(self, name, stype, port, domain="", host=""): 
 28          """ 
 29          Publish a named service on the local zeroconf network. 
 30          """ 
 31          if name in self.published: 
 32              return 
 33   
 34          if not self.bus: 
 35              self.bus = dbus.SystemBus() 
 36   
 37          server = dbus.Interface( 
 38                           self.bus.get_object( 
 39                                   avahi.DBUS_NAME, 
 40                                   avahi.DBUS_PATH_SERVER), 
 41                          avahi.DBUS_INTERFACE_SERVER) 
 42   
 43          g = dbus.Interface( 
 44                      self.bus.get_object(avahi.DBUS_NAME, 
 45                                     server.EntryGroupNew()), 
 46                      avahi.DBUS_INTERFACE_ENTRY_GROUP) 
 47   
 48          g.AddService(avahi.IF_UNSPEC, avahi.PROTO_UNSPEC,dbus.UInt32(0), 
 49                       name, stype, domain, host, 
 50                       dbus.UInt16(port), "") 
 51   
 52          g.Commit() 
 53          self.published[name] = g 
 54   
 55   
 56 -    def unpublishService(self, name): 
 57          """ 
 58          Revoke a previously published service. 
 59          """ 
 60          self.published[name].Reset() 
 61          del self.published[name] 
 62   
 63   
 64 -    def unpublishAllServices(self): 
 65          """ 
 66          Revoke all published services. 
 67          """ 
 68          for k in self.published.keys(): 
 69              self.unpublishService(k) 
 70   
 71   
 72   
 73 -    def subscribeTo(self, serviceType): 
 74          """ 
 75          Subscribe to a specific service. 
 76          """ 
 77          if serviceType in self.subscribed: 
 78              return 
 79   
 80          if not self.bus: 
 81              self.bus = dbus.SystemBus() 
 82          if not self.server: 
 83              self.server = dbus.Interface( self.bus.get_object(avahi.DBUS_NAME, '/'), 'org.freedesktop.Avahi.Server') 
 84   
 85          sbrowser = dbus.Interface(self.bus.get_object(avahi.DBUS_NAME, 
 86                                                        self.server.ServiceBrowserNew(avahi.IF_UNSPEC, 
 87                                                                                      avahi.PROTO_UNSPEC, serviceType, 'local', dbus.UInt32(0))), 
 88                                                                      avahi.DBUS_INTERFACE_SERVICE_BROWSER) 
 89          sbrowser.connect_to_signal("ItemNew", self._itemNew) 
 90          sbrowser.connect_to_signal("ItemRemove", self._itemRemove) 
 91          self.subscribed.append(serviceType) 
 92   
 93   
 94      # Avahi handler functions 
 95   
 96 -    def _itemNew(self, iface, protocol, name, stype, domain, flags): 
 97   
 98          def resolveError(*a): 
 99              log.msg("RESOLVE ERROR:") 
100              log.err(a) 
101   
102          def resolveSuccess(*args): 
103              name = args[2] 
104              hostname = args[5] 
105              address = args[7] 
106              port = args[8] 
107              log.msg("** New service: %s (%s@%s)" % (name, hostname, port)) 
108              zeroconfEvents.dispatch("service-found", name, hostname=hostname, address=address, port=port, type=stype) 
109   
110          self.server.ResolveService(iface, protocol, name, stype,  
111                                     domain, avahi.PROTO_UNSPEC, dbus.UInt32(0),  
112                                     reply_handler=resolveSuccess, error_handler=resolveError) 
113   
114   
115   
116 -    def _itemRemove(self, iface, protocol, name, stype, domain, flags): 
117          log.msg("** Service lost: %s" % name) 
118          zeroconfEvents.dispatch("service-lost", name, type=stype) 
119   
120   
121  try: 
122      zeroconfService 
123  except NameError: 
124      zeroconfService = _ZeroconfService() 
125      zeroconfEvents = events.EventDispatcher() 
126   
127   
128  __all__  = ['zeroconfService', 'zeroconfEvents'] 
129