Is it possible to pair with passkey?.

[vChavezB]

I am looking to pair with a device I know its passkey and I would like to know if its possible to pair with a given passkey.

[dlech]

It should be possible.

[vChavezB]

yes, there is a pair function in https://github.com/hbldh/bleak/blob/develop/bleak/backends/bluezdbus/client.py#L323 but I do not see how you enter such pass key.

What I found so far is that you can use an agent to set the passkey. I will probably try this

https://stackoverflow.com/a/37487500

[dlech]

Related: #640

[vChavezB]

What I found so far is to create a thread that processes the pair request with dbus

IanHarvey/bluepy#450

https://gist.github.com/castis/0b7a162995d0b465ba9c84728e60ec01

[vChavezB]

This is by no means production code but rather a quick solution so I can pair with devices in python.

Agent Module to pair (runs in a thread)

import dbus
import dbus.service
import dbus.mainloop.glib
from gi.repository import GLib
import threading

BUS_NAME = 'org.bluez'
ADAPTER_IFACE = 'org.bluez.Adapter1'
ADAPTER_ROOT = '/org/bluez/hci'
AGENT_IFACE = 'org.bluez.Agent1'
AGNT_MNGR_IFACE = 'org.bluez.AgentManager1'
AGENT_PATH = '/my/app/agent'
AGNT_MNGR_PATH = '/org/bluez'
CAPABILITY = 'KeyboardDisplay'
DEVICE_IFACE = 'org.bluez.Device1'
dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)
bus = dbus.SystemBus()

passkey = None

def set_trusted(path):
    props = dbus.Interface(bus.get_object(BUS_NAME, path), dbus.PROPERTIES_IFACE)
    props.Set(DEVICE_IFACE, "Trusted", True)

class Agent(dbus.service.Object):

    @dbus.service.method(AGENT_IFACE,
                         in_signature="", out_signature="")
    def Release(self):
        print("Release")

    @dbus.service.method(AGENT_IFACE,
                         in_signature='o', out_signature='s')
    def RequestPinCode(self, device):
        print(f'RequestPinCode {device}')
        return '0000'

    @dbus.service.method(AGENT_IFACE,
                         in_signature="ou", out_signature="")
    def RequestConfirmation(self, device, passkey):
        print("RequestConfirmation (%s, %06d)" % (device, passkey))
        set_trusted(device)
        return

    @dbus.service.method(AGENT_IFACE,
                         in_signature="o", out_signature="")
    def RequestAuthorization(self, device):
        print("RequestAuthorization (%s)" % (device))
        auth = input("Authorize? (yes/no): ")
        if (auth == "yes"):
            return
        raise Rejected("Pairing rejected")

    @dbus.service.method(AGENT_IFACE,
                         in_signature="o", out_signature="u")
    def RequestPasskey(self, device):
        global passkey
        print("RequestPasskey (%s)" % (device))
        print(passkey)
        if(passkey==None):
            return dbus.UInt32("000000")
        else:
            return dbus.UInt32(passkey)
        #set_trusted(device)
        return dbus.UInt32(passkey)

    @dbus.service.method(AGENT_IFACE,
                         in_signature="ouq", out_signature="")
    def DisplayPasskey(self, device, passkey, entered):
        print("DisplayPasskey (%s, %06u entered %u)" %
              (device, passkey, entered))

    @dbus.service.method(AGENT_IFACE,
                         in_signature="os", out_signature="")
    def DisplayPinCode(self, device, pincode):
        print("DisplayPinCode (%s, %s)" % (device, pincode))


class Adapter:
    def __init__(self, idx=0):
        bus = dbus.SystemBus()
        self.path = f'{ADAPTER_ROOT}{idx}'
        self.adapter_object = bus.get_object(BUS_NAME, self.path)
        self.adapter_props = dbus.Interface(self.adapter_object,
                                            dbus.PROPERTIES_IFACE)
        self.adapter_props.Set(ADAPTER_IFACE,
                               'DiscoverableTimeout', dbus.UInt32(0))
        self.adapter_props.Set(ADAPTER_IFACE,
                               'Discoverable', True)
        self.adapter_props.Set(ADAPTER_IFACE,
                               'PairableTimeout', dbus.UInt32(0))
        self.adapter_props.Set(ADAPTER_IFACE,
                               'Pairable', True)

class BluetoothAgent:
    def __init__(self, idx=0):
        self.agent = Agent(bus, AGENT_PATH)
        self.agnt_mngr = dbus.Interface(bus.get_object(BUS_NAME, AGNT_MNGR_PATH),
                                   AGNT_MNGR_IFACE)
        self.passkey = None
    def agent_loop(self):
        try:
            self.mainloop.run()
        except Exception:
            self.agnt_mngr.UnregisterAgent(AGENT_PATH)
            self.mainloop.quit()
    def start(self):
        self.agnt_mngr.RegisterAgent(AGENT_PATH, CAPABILITY)
        self.agnt_mngr.RequestDefaultAgent(AGENT_PATH)
        adapter = Adapter()
        self.mainloop = GLib.MainLoop()
        th = threading.Thread(target=self.agent_loop)
        th.start()
    def stop(self):
        self.agnt_mngr.UnregisterAgent(AGENT_PATH)
        self.mainloop.quit()
    def set_passkey(self,user_passkey):
        global passkey
        passkey= user_passkey

[vChavezB]

And to use it with bleak

import BluetoothAgent

agent = BluetoothAgent.agent
agent.start()
#Insert your code to get a device through scan, filter,etc
client = BleakClient(device) #assumes you already have a device
await client.connect()
agent.set_passkey("001235")
await client.pair()

This is just for information if anyone wants to integrate it into bleak. As my use case is only changing the passkey, most of the other Dbus callbacks for the Agent are not used.

[thedaoo-spectra]

if agent.set_passkey() is not used, will client.pair() open a windows dialog box requested for a passkey ?

[vChavezB]

Its been a while that I wrote this snippet. I am not sure if bleak opens a dialog box, check the source code of bleak, the project is open source ;).

The Agent class method RequestPasskey is called when a passkey is requested.

[thedaoo-spectra]

cool :D i am gonna take a look at the source code. I will give this a swing and let you know how it goes. Thanks !

[vChavezB]

I had a quick look on updates on bleak, it could be that this is already implemented

see here

https://github.com/hbldh/bleak/pull/1100/files#diff-8660c0e17619e3634de3cccbe28fe02e73a18f27aac1b5a27a8937d6c2d3c0eeR70

and more specific the PR

#1100

[snowuyl]

Does bleak development team have plan to integrate class BluetoothAgent to bleak formal release? Or does bleak development team have plans to support pair with key features?