Dragbox/dbuscontrol.py

   1 # Copyright (C) 2006, 2007 Ulrik Sverdrup
   2 #
   3 #   dragbox -- Commandline drag-and-drop tool for GNOME
   4 #
   5 # This program is free software; you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation; either version 2 of the License, or
   8 # (at your option) any later version.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program; if not, write to the Free Software
  17 # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
  18 # USA
  19
  20 class Error(Exception):
  21         pass
  22
  23 class ServiceUnavailable(Error):
  24         pass
  25
  26 class NotEnabledError(ImportError, Error):
  27         pass
  28
  29 def _clear_dbus_environment():
  30         """
  31         This is an evil run-on-import function to reset
  32         dbus' environment
  33
  34         Here we try unsetting DBUS_SESSION_BUS_ADDRESS to
  35         make dbus recover it from the current X session.
  36         (debian bug #475448)
  37         """
  38         from os import unsetenv, getenv
  39         from utils import print_debug
  40         bus_address_env_name = "DBUS_SESSION_BUS_ADDRESS"
  41         bus = None
  42
  43         print_debug("Unsetting %s, to defend against stale environment" %
  44                         bus_address_env_name)
  45         unsetenv(bus_address_env_name)
  46
  47 _clear_dbus_environment()
  48 try:
  49         import dbus
  50         from dbus.mainloop.glib import DBusGMainLoop
  51         DBusGMainLoop(set_as_default=True)
  52         from dbus.gobject_service import ExportedGObject
  53 except:
  54         raise NotEnabledError("Dbus not available")
  55
  56 import gobject
  57
  58 default_object_path = "/default"
  59 service_interface = "org.gna.DragboxInterface"
  60 default_service_name = "org.gna.dragbox"
  61
  62 class Service(ExportedGObject):
  63         """
  64         Provides a dbus server controller
  65
  66         Exported interface methods:
  67         activate - sends signal activate
  68         send_files - sends signal files-received
  69         send_texts - sends signal texts-received
  70
  71         send_file, send_text: Send single objects. These
  72         exported methods are for external methods to simplify
  73         their interaction with dragbox.
  74
  75         data-requested signal: parameters send_callback and error_callback
  76         on error, call error_callback with an exception instance. otherwise
  77         send_callback should be called with two lists: datas, types.
  78         """
  79         __gtype_name__ = "Service"
  80
  81         @dbus.service.method(service_interface)
  82         def send_file(self, f):
  83                 """
  84                 f: absolute path
  85                 """
  86                 self.send_files([f])
  87
  88         @dbus.service.method(service_interface)
  89         def send_files(self, data):
  90                 """
  91                 data: list of absolute paths
  92                 """
  93                 self.emit("files-received", data)
  94
  95         @dbus.service.method(service_interface)
  96         def send_text(self, t):
  97                 """
  98                 t: text string
  99                 """
 100                 self.send_texts([t])
 101
 102         @dbus.service.method(service_interface)
 103         def send_texts(self, data):
 104                 """
 105                 data: list of text strings
 106                 """
 107                 self.emit("texts-received", data)
 108
 109         @dbus.service.method(service_interface)
 110         def activate(self):
 111                 """
 112                 activate application (bring to front)
 113                 """
 114                 self.emit("activate")
 115
 116         @dbus.service.method(service_interface, out_signature="asas",
 117                         async_callbacks=("send_callback", "error_callback"))
 118         def get_data(self, send_callback, error_callback):
 119                 """
 120                 activate application (bring to front)
 121                 """
 122                 self.emit("data-requested", send_callback, error_callback)
 123
 124 # See Service class declaration for
 125 # documentation of the signals
 126 gobject.type_register(Service)
 127 gobject.signal_new("files-received", Service, gobject.SIGNAL_RUN_LAST,
 128                 gobject.TYPE_BOOLEAN, (gobject.TYPE_PYOBJECT, ))
 129 gobject.signal_new("texts-received", Service, gobject.SIGNAL_RUN_LAST,
 130                 gobject.TYPE_BOOLEAN, (gobject.TYPE_PYOBJECT, ))
 131 gobject.signal_new("activate", Service, gobject.SIGNAL_RUN_LAST,
 132                 gobject.TYPE_BOOLEAN, ())
 133 gobject.signal_new("data-requested", Service, gobject.SIGNAL_RUN_LAST,
 134                 gobject.TYPE_BOOLEAN, (gobject.TYPE_PYOBJECT, gobject.TYPE_PYOBJECT))
 135
 136 def make_service(identifier=None):
 137         """
 138         Return a service object
 139
 140         identifier: The service identifier, or None to use the default
 141         """
 142         service_name = _make_service_name(identifier)
 143         session_bus = dbus.SessionBus()
 144         bus_name = dbus.service.BusName(service_name, bus=session_bus)
 145         # return an instance of the Service
 146         return Service(bus_name, object_path=default_object_path)
 147
 148 def _make_service_name(identifier):
 149         """
 150         Make a service name from the string identifier
 151
 152         Return default service name if identifier is None
 153         """
 154         if identifier:
 155                 accept = "abcdefghijklmnopqrstuvwxyz"
 156                 name = "".join(c for c in identifier.lower() if c in accept)
 157                 identifier = name
 158         if not identifier:
 159                 return default_service_name
 160         else:
 161                 return default_service_name + "." + identifier
 162
 163 def _get_dbus_interface(bus):
 164         """
 165         Return the interface of the main dbus object on the given bus
 166         """
 167         dbus_name = 'org.freedesktop.DBus'
 168         dbus_object_path = '/org/freedesktop/DBus'
 169         dbusobj =  bus.get_object(dbus_name, dbus_object_path)
 170         return dbus.Interface(dbusobj, dbus_name)
 171
 172 def _get_dbus_session_bus():
 173         """
 174         Get the dbus SessionBus
 175
 176         Raises ServiceUnavailable if dbus is not available
 177         """
 178         from utils import print_debug
 179         bus = None
 180
 181         try:
 182                 bus = dbus.SessionBus()
 183         except:
 184                 raise ServiceUnavailable("Could not get dbus session bus")
 185         return bus
 186
 187 def list_names():
 188         """
 189         Yield available dragbox services by identifier
 190         """
 191         bus = _get_dbus_session_bus()
 192         iface = _get_dbus_interface(bus)
 193         bus_names = iface.ListNames()
 194         for name in bus_names:
 195                 if name.startswith(default_service_name):
 196                         if name == default_service_name:
 197                                 yield "(default)"
 198                         else:
 199                                 basename = name.replace(default_service_name + ".", "")
 200                                 yield basename
 201
 202 class Connection(object):
 203         """
 204         Tries to connect to previously started Service
 205         """
 206         def __init__(self, identifier=None):
 207                 """
 208                 Create a connection to a running instance
 209
 210                 identifier: service identifier, or None to use the default
 211
 212                 Throws ServiceUnavailable if no service found
 213                 """
 214                 bus = _get_dbus_session_bus()
 215
 216                 service_name = _make_service_name(identifier)
 217                 # Check with dbus if service is available
 218                 dbusiface = _get_dbus_interface(bus)
 219                 if dbusiface.NameHasOwner(service_name):
 220                                 proxy_obj = bus.get_object(service_name, default_object_path)
 221                                 if proxy_obj:
 222                                         self.iface = dbus.Interface(proxy_obj, service_interface)
 223                                         return
 224                 self.iface = None
 225                 raise ServiceUnavailable("%s not found" % service_name)
 226
 227         def get_interface(self):
 228                 """
 229                 Returns the dbus interface to the "Service"
 230                 """
 231                 return self.iface
 232