running Bluez 4.x without GUI

Recently I have tried to run bluetooth on my Fedora12 installation. It seems bluetooth works fine only if GUI is used. BlueZ (Linux bluetooth stack implementation) heavily relies on DBUS. Unfortunately there is no support for pairing devices (PIN entry) when no GUI is available. Every post on the internet regarding non GUI bluetooth setup is just useless as it references pre 4.x bluez setup. Bluez seems to have changed a lot in 4.x versions. There is almost no documentation.

The recommended way was to use the default passkey-agent. But it seems not to work anymore.

Finaly I was able to pair may device using sample agent found in bluez sources test/simple-agent which is configurable. I have modified the source slightly to pair using constant PIN. When started the code bellow will respond with constant PIN to every pairing request. The constant PIN is 1243.

Usage: store the following code into a file. Change attributes of the file to be runnable (chmod a+x filename). Then run the script. Then you will be able to pair devices using the default PIN 1243.

#!/usr/bin/python

import gobject

import sys
import dbus
import dbus.service
import dbus.mainloop.glib

class Rejected(dbus.DBusException):
        _dbus_error_name = "org.bluez.Error.Rejected"

class Agent(dbus.service.Object):
        exit_on_release = True

        def set_exit_on_release(self, exit_on_release):
                self.exit_on_release = exit_on_release

        @dbus.service.method("org.bluez.Agent",
                                        in_signature="", out_signature="")
        def Release(self):
                print "Release"
                if self.exit_on_release:
                        mainloop.quit()

        @dbus.service.method("org.bluez.Agent",
                                        in_signature="os", out_signature="")
        def Authorize(self, device, uuid):
                print "Authorize"
                return

        @dbus.service.method("org.bluez.Agent",
                                        in_signature="o", out_signature="s")
        def RequestPinCode(self, device):
                print "RequestPinCode"
                return "1243"

        @dbus.service.method("org.bluez.Agent",
                                        in_signature="o", out_signature="u")
        def RequestPasskey(self, device):
                print "RequestPasskey"
                return dbus.UInt32("1243")

        @dbus.service.method("org.bluez.Agent",
                                        in_signature="ou", out_signature="")
        def DisplayPasskey(self, device, passkey):
                print "DisplayPasskey"
                return

        @dbus.service.method("org.bluez.Agent",
                                        in_signature="ou", out_signature="")
        def RequestConfirmation(self, device, passkey):
                print "RequestConfirmation"
                return

        @dbus.service.method("org.bluez.Agent",
                                        in_signature="s", out_signature="")
        def ConfirmModeChange(self, mode):
                print "ConfirmModeChange (%s)" % (mode)

        @dbus.service.method("org.bluez.Agent",
                                        in_signature="", out_signature="")
        def Cancel(self):
                print "Cancel"

def create_device_reply(device):
        print "New device (%s)" % (device)
        mainloop.quit()

def create_device_error(error):
        print "Creating device failed: %s" % (error)
        mainloop.quit()

if __name__ == '__main__':
        dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)
        print "Step 1"

        bus = dbus.SystemBus()
        print "System bus acquired"

        manager = dbus.Interface(bus.get_object("org.bluez", "/"),
                                                        "org.bluez.Manager")
        print "manager acquired"

        path = manager.DefaultAdapter()
        print "Manager path acquired"

        adapter = dbus.Interface(bus.get_object("org.bluez", path),
                                                        "org.bluez.Adapter")
        print "adapter acquired"

        path = "/my/agent"
        agent = Agent(bus, path)
        print "Agent object created"

        mainloop = gobject.MainLoop()
        print "Main loop created"

        adapter.RegisterAgent(path, "NoInputNoOutput")
        print "Agent registered"

        print "Starting loop"
        mainloop.run()

        #adapter.UnregisterAgent(path)
        #print "Agent unregistered"