I have gotten a python3 (mostly) abstracted versions of the example-gatt-server and example-advertise working. Basically had to add the “Application” thing from the previous 5.37 based versions. They are relatively small and attached. Hardest part was throwing darts at the difference between the python3 dbus interface and the python2 dbus interface. It works, but who knows how idiomatic it is.
I’m confused by many things (at least 6) though.
Right after startup, without running any of my own code:
~# mdbus2 --system org.bluez / org.freedesktop.DBus.ObjectManager.GetManagedObjects
({'/org/bluez': {'org.freedesktop.DBus.Introspectable': {}, 'org.bluez.AgentManager1': {}, 'org.bluez.ProfileManager1': {}, 'org.bluez.Alert1': {}, 'org.bluez.HealthManager1': {}}, '/org/bluez/hci0': {'org.freedesktop.DBus.Introspectable': {}, 'org.bluez.Adapter1': {'Address': <'5C:F3:70:68:C1:F9'>, 'Name': <'nelson'>, 'Alias': <'PILOT-FF0021'>, 'Class': <uint32 0>, 'Powered': <true>, 'Discoverable': <false>, 'DiscoverableTimeout': <uint32 180>, 'Pairable': <true>, 'PairableTimeout': <uint32 0>, 'Discovering': <false>, 'UUIDs': <['00001801-0000-1000-8000-00805f9b34fb', '0000110e-0000-1000-8000-00805f9b34fb', '00001200-0000-1000-8000-00805f9b34fb', '00001800-0000-1000-8000-00805f9b34fb', '0000110c-0000-1000-8000-00805f9b34fb']>, 'Modalias': <'usb:v1D6Bp0246d0526'>}, 'org.freedesktop.DBus.Properties': {}, 'org.bluez.GattManager1': {}, 'org.bluez.Media1': {}, 'org.bluez.CyclingSpeedManager1': {}, 'org.bluez.HeartRateManager1': {}, 'org.bluez.ThermometerManager1': {}, 'org.bluez.LEAdvertisingManager1': {}}},)
1) A GattManager and a LEAdvertisingManager are things I expected. But a CycleSpeedManager? And a HeartRateManager? I don’t understand why these are there. Is it because I have the -E turned on. Are they just temporary during the development phase while that is experimental? I thought there was quite a few of these predefined services and characteristics, and here see a few, but far from all. I *think* those UUIDs match up with some of the manager things?
2) How does it know that my Alias is ‘PILOT-FF0021’ ? My code does set that, but this was after I had pulled the dongle out, shutdown the SBC, plugged it back in, and then started it up. Is that being written into the dongle’s non volatile memory somehow??
Now, I run some python code that turns on advertising, but register no services:
class PilotAdvertisement(ble_advertise.Advertisement):
def __init__(self, bus):
super().__init__(bus, 'peripheral')
self.add_service_uuid(MainService.UUID)
self.include_tx_power = True
Adapter = '/org/bluez/hci0'
def main():
dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)
bus = dbus.SystemBus()
advertisingManager = dbus.Interface(bus.get_object('org.bluez', Adapter), ble_advertise.LE_ADVERTISING_MANAGER_IFACE)
advertisement = PilotAdvertisement(bus)
advertisingManager.RegisterAdvertisement(advertisement.get_path(), {}, reply_handler=registerAdvertisementSuccess, error_handler=registerAdvertisementFail)
mainloop = glib.MainLoop()
try:
mainloop.run()
except KeyboardInterrupt:
mainloop.quit()
And then connect to the device using the LightBlue iOS app...
3) Suddenly, I have all kinds of object paths in org.bluez that I can’t identify
# mdbus2 --system org.bluez
/
/org
/org/bluez
/org/bluez/hci0
/org/bluez/hci0/dev_5E_41_16_18_F6_37
/org/bluez/hci0/dev_5E_41_16_18_F6_37/service000a
/org/bluez/hci0/dev_5E_41_16_18_F6_37/service000a/char000b
/org/bluez/hci0/dev_5E_41_16_18_F6_37/service000a/char000b/desc000d
/org/bluez/hci0/dev_5E_41_16_18_F6_37/service000a/char000b/desc000e
<snipped 10+ lines>
/org/bluez/hci0/dev_5E_41_16_18_F6_37/service0028/char0031
/org/bluez/hci0/dev_5E_41_16_18_F6_37/service0028/char0031/desc0033
Are these related to those various predefined services I was asking about? Or are they just generalized meta data that comes along with any connection? What confuses me is that LightBlue on my phone shoes no characteristics to play with. But I can see that the advertising data does indeed include the single service UUID that _I_ added to it. It doesn’t seem to advertise any of these other services.
Now I add my own service with two characteristics (one write, one notify) by registering an Application that has the single service.
serviceManager = dbus.Interface(bus.get_object('org.bluez', Adapter), ble_gatt.GATT_MANAGER_IFACE)
application = ble_gatt.Application(bus)
application.add_service(MainService(bus, 0))
serviceManager.RegisterApplication(application.get_path(), {}, reply_handler=registerApplicationSuccess, error_handler=registerApplicationFail)
And then connect. LightBlue now sees 2 characteristics correctly identified.
4) The query shown above doesn’t change. It still has the same output. This further leads me to believe those are meta services/characteristics independent of the example ones? Is there any way to know what they are?
5) On line 60 of the attached ble_gatt.py, I am setting PATH_BASE = '/com/nelson_irrigation/pilot/service’. This is being used to construct the paths for the service, characteristics, and descriptors. But I don’t see this path anywhere in mdbus2 queries. Where is it at?
6) I can change the `write` characteristic value from LightBlue, and my subclass override of WriteValue successfully print()’s the newly arrived value. But with `dbus-monitor —system` running, I see no traffic there. Do I need to run dbus-monitor in a more specific fashion?
TIA
#!/usr/bin/env python3
import dbus
import dbus.exceptions
import dbus.mainloop.glib
import dbus.service
LE_ADVERTISING_MANAGER_IFACE = 'org.bluez.LEAdvertisingManager1'
LE_ADVERTISEMENT_IFACE = 'org.bluez.LEAdvertisement1'
DBUS_PROP_IFACE = 'org.freedesktop.DBus.Properties'
class InvalidArgsException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.freedesktop.DBus.Error.InvalidArgs'
class NotSupportedException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.bluez.Error.NotSupported'
class NotPermittedException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.bluez.Error.NotPermitted'
class InvalidValueLengthException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.bluez.Error.InvalidValueLength'
class FailedException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.bluez.Error.Failed'
class Advertisement(dbus.service.Object):
PATH_BASE = '/nelson_irrigation/twig_pilot'
def __init__(self, bus, advertising_type):
self.path = self.PATH_BASE
self.bus = bus
self.ad_type = advertising_type
self.service_uuids = None
self.manufacturer_data = None
self.solicit_uuids = None
self.service_data = None
self.include_tx_power = None
dbus.service.Object.__init__(self, bus, self.path)
def get_properties(self):
properties = dict()
properties['Type'] = self.ad_type
if self.service_uuids is not None:
properties['ServiceUUIDs'] = dbus.Array(self.service_uuids, signature='s')
if self.solicit_uuids is not None:
properties['SolicitUUIDs'] = dbus.Array(self.solicit_uuids, signature='s')
if self.manufacturer_data is not None:
properties['ManufacturerData'] = dbus.Dictionary(self.manufacturer_data, signature='qay')
if self.service_data is not None:
properties['ServiceData'] = dbus.Dictionary(self.service_data, signature='say')
if self.include_tx_power is not None:
properties['IncludeTxPower'] = dbus.Boolean(self.include_tx_power)
return {LE_ADVERTISEMENT_IFACE: properties}
def get_path(self):
return dbus.ObjectPath(self.path)
def add_service_uuid(self, uuid):
if not self.service_uuids:
self.service_uuids = []
self.service_uuids.append(uuid)
def add_solicit_uuid(self, uuid):
if not self.solicit_uuids:
self.solicit_uuids = []
self.solicit_uuids.append(uuid)
def add_manufacturer_data(self, manuf_code, data):
if not self.manufacturer_data:
self.manufacturer_data = dict()
self.manufacturer_data[manuf_code] = data
def add_service_data(self, uuid, data):
if not self.service_data:
self.service_data = dict()
self.service_data[uuid] = data
@dbus.service.method(DBUS_PROP_IFACE, in_signature='s', out_signature='a{sv}')
def GetAll(self, interface):
if interface != LE_ADVERTISEMENT_IFACE:
raise InvalidArgsException()
return self.get_properties()[LE_ADVERTISEMENT_IFACE]
@dbus.service.method(LE_ADVERTISEMENT_IFACE, in_signature='', out_signature='')
def Release(self):
print('{}: Released!'.format(self.path))#!/usr/bin/env python3
import dbus
import dbus.exceptions
import dbus.mainloop.glib
import dbus.service
GATT_MANAGER_IFACE = 'org.bluez.GattManager1'
DBUS_OM_IFACE = 'org.freedesktop.DBus.ObjectManager'
DBUS_PROP_IFACE = 'org.freedesktop.DBus.Properties'
GATT_SERVICE_IFACE = 'org.bluez.GattService1'
GATT_CHRC_IFACE = 'org.bluez.GattCharacteristic1'
GATT_DESC_IFACE = 'org.bluez.GattDescriptor1'
class InvalidArgsException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.freedesktop.DBus.Error.InvalidArgs'
class NotSupportedException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.bluez.Error.NotSupported'
class NotPermittedException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.bluez.Error.NotPermitted'
class InvalidValueLengthException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.bluez.Error.InvalidValueLength'
class FailedException(dbus.exceptions.DBusException):
_dbus_error_name = 'org.bluez.Error.Failed'
class Application(dbus.service.Object):
def __init__(self, bus):
self.path = '/'
self.services = []
dbus.service.Object.__init__(self, bus, self.path)
def get_path(self):
return dbus.ObjectPath(self.path)
def add_service(self, service):
self.services.append(service)
@dbus.service.method(DBUS_OM_IFACE, out_signature='a{oa{sa{sv}}}')
def GetManagedObjects(self):
response = {}
for service in self.services:
response[service.get_path()] = service.get_properties()
chrcs = service.get_characteristics()
for chrc in chrcs:
response[chrc.get_path()] = chrc.get_properties()
descs = chrc.get_descriptors()
for desc in descs:
response[desc.get_path()] = desc.get_properties()
return response
class Service(dbus.service.Object):
PATH_BASE = '/com/nelson_irrigation/pilot/service'
def __init__(self, bus, index, uuid, primary):
self.path = self.PATH_BASE + str(index)
self.bus = bus
self.uuid = uuid
self.primary = primary
self.characteristics = []
dbus.service.Object.__init__(self, bus, self.path)
def get_properties(self):
return {
GATT_SERVICE_IFACE: {
'UUID': self.uuid,
'Primary': self.primary,
'Characteristics': dbus.Array(self.get_characteristic_paths(), signature='o')
}
}
def get_path(self):
return dbus.ObjectPath(self.path)
def add_characteristic(self, characteristic):
self.characteristics.append(characteristic)
def get_characteristic_paths(self):
result = []
for characteristic in self.characteristics:
result.append(characteristic.get_path())
return result
def get_characteristics(self):
return self.characteristics
@dbus.service.method(DBUS_PROP_IFACE, in_signature='s', out_signature='a{sv}')
def GetAll(self, interface):
if interface != GATT_SERVICE_IFACE:
raise InvalidArgsException()
return self.get_properties[GATT_SERVICE_IFACE]
class Characteristic(dbus.service.Object):
def __init__(self, bus, index, uuid, flags, service):
self.path = service.path + '/char' + str(index)
self.bus = bus
self.uuid = uuid
self.service = service
self.flags = flags
self.descriptors = []
dbus.service.Object.__init__(self, bus, self.path)
def get_properties(self):
return {
GATT_CHRC_IFACE: {
'Service': self.service.get_path(),
'UUID': self.uuid,
'Flags': self.flags,
'Descriptors': dbus.Array(self.get_descriptor_paths(), signature='o')
}
}
def get_path(self):
return dbus.ObjectPath(self.path)
def add_descriptor(self, descriptor):
self.descriptors.append(descriptor)
def get_descriptor_paths(self):
result = []
for descriptor in self.descriptors:
result.append(descriptor.get_path())
return result
def get_descriptors(self):
return self.descriptors
@dbus.service.method(DBUS_PROP_IFACE, in_signature='s', out_signature='a{sv}')
def GetAll(self, interface):
if interface != GATT_CHRC_IFACE:
raise InvalidArgsException()
return self.get_properties[GATT_CHRC_IFACE]
@dbus.service.method(GATT_CHRC_IFACE, out_signature='ay')
def ReadValue(self):
print('Default ReadValue called, returning error')
raise NotSupportedException()
@dbus.service.method(GATT_CHRC_IFACE, in_signature='ay')
def WriteValue(self, value):
print('Default WriteValue called, returning error')
raise NotSupportedException()
@dbus.service.method(GATT_CHRC_IFACE)
def StartNotify(self):
print('Default StartNotify called, returning error')
raise NotSupportedException()
@dbus.service.method(GATT_CHRC_IFACE)
def StopNotify(self):
print('Default StopNotify called, returning error')
raise NotSupportedException()
@dbus.service.signal(DBUS_PROP_IFACE, signature='sa{sv}as')
def PropertiesChanged(self, interface, changed, invalidated):
pass
class Descriptor(dbus.service.Object):
def __init__(self, bus, index, uuid, flags, characteristic):
self.path = characteristic.path + '/desc' + str(index)
self.bus = bus
self.uuid = uuid
self.flags = flags
self.chrc = characteristic
dbus.service.Object.__init__(self, bus, self.path)
def get_properties(self):
return {
GATT_DESC_IFACE: {
'Characteristic': self.chrc.get_path(),
'UUID': self.uuid,
'Flags': self.flags,
}
}
def get_path(self):
return dbus.ObjectPath(self.path)
@dbus.service.method(DBUS_PROP_IFACE, in_signature='s', out_signature='a{sv}')
def GetAll(self, interface):
if interface != GATT_DESC_IFACE:
raise InvalidArgsException()
return self.get_properties[GATT_CHRC_IFACE]
@dbus.service.method(GATT_DESC_IFACE, out_signature='ay')
def ReadValue(self):
print ('Default ReadValue called, returning error')
raise NotSupportedException()
@dbus.service.method(GATT_DESC_IFACE, in_signature='ay')
def WriteValue(self, value):
print('Default WriteValue called, returning error')
raise NotSupportedException()
