custom service and chars issue

[freedreamer82]

hello,

i've been trying to setup a custom service with 2 chars but following your example and connecting eith my phone I see a service but without chars.

below the code

s1, err := a.NewService()
    if err != nil {
        return err
    }

    c1, err := s1.NewChar()
    if err != nil {
        return err
    }

    err = s1.AddChar(c1)
    if err != nil {
        return err
    }

    c1.OnRead(service.CharReadCallback(func(c *service.Char, options map[string]interface{}) ([]byte, error) {
        log.Warnf("GOT READ REQUEST")
        return []byte{42}, nil
    }))
    c1.OnWrite(service.CharWriteCallback(func(c *service.Char, value []byte) ([]byte, error) {
        log.Warnf("GOT WRITE REQUEST")
        return value, nil
    }))

    d1, err := c1.NewDescr()
    if err != nil {
        return err
    }

    err = c1.AddDescr(d1)
    if err != nil {
        return err
    }

    err = a.AddService(s1)
    if err != nil {
        return err
    }

    err = a.Run()
    if err != nil {
        return err
    }

moreover if I want to customize a new service app with my UUID how should I do ? from the doc is not clear...

thanks for the great work!

Marco

[muka]

Hi Marco thank you for the issue. It's a bit I am not working on the repo, I need to give check if there is any bug or incosistency with bluez interfaces.

There is also an example folder with some more details

[freedreamer82]

Hi Luca,

I really like the project and it is what i need.Could you please double check if does it work on your side? Moreover the service interface to me should be changed in order to simplify the creation of a custom service (maybe passing the UUID in the NewMethod for example).

if the project really does what I need I can contribute with PR if necessary. I do not want to use gatt paypal library :)

Thanks

Marco

[muka]

If you have the time to work on a PR it would be great!

Let me know if I can provide support somehow

[freedreamer82]

Of course I can work on a PR. BTW I would start on it if i'm sure the lib can do what I need.If you can check your example and get it to work I'll modify the service trying to make it more generic. Right now i'm using paypal lib and works pretty well but it's not integrated with bluez dbus and I would like to use bluetoothd .

thanks again

Marco

[mattwallington]

I am also having this issue. I can create custom services but the characteristics and descriptors don't show up.

[muka]

Hi @freedreamer82 @mattwallington I will try to sort this out. I have the same issue

[mattwallington]

Much appreciated!

[mattwallington]

@muka I have been using Bluez 5.50. Do you think the issue might be a spec change or something? Perhaps rolling back to a previous Bluez version would solve the issues? If so, do you have a version you would recommend that is known to be working? Thanks so much for this library and all the work you've put into it.

[freedreamer82]

hi, news?

[muka]

Hello, an Eastern update that surely will drive us in the right direction..

I refactored a bit the generation code and added a docker based build that should simplify testing across bluez versions (branch bluez-5.54).

I am testing with 5.54 to see if there are differences. Additionally, I will rebuild the service to be aligned to the python example in the bluez repository. I'd expect the interoperability of the two example and to spot the bug(s) that way. :tada:

[muka]

Good news, the service seems to work now. It was missing the btmgmt le on command.

I will work more on the examples so that the example client read, write and subscribe to the example service

[freedreamer82]

I ll try it. btw remains the issue to customize uuid of the customer service.could u Expose a method?

Thanks

[muka]

Sure I will, if you want to provide a PR while testing I will be happy to merge it. Thanks

[mattwallington]

Awesome news. Thank you for fixing that!

[freedreamer82]

I tried but i have the same issue with my iphone and lightblue app. It sees the device but no services and chars.

already did a "btmgmt le on"

I'm on ubuntu bluez 5.50

[muka]

Ok, I have the suspect 5.50 is not really playing nice with services (as @mattwallington suggested)

Can you try to run on bluez 5.54 ?

An example (requires docker):

cd <path>/go-bluetooth
git checkout master && git pull
make docker/bluetoothd/run
./bin/docker-btmgmt -i hci0 le on
./bin/docker-btmgmt -i hci0 bredr off
./bin/docker-btmgmt -i hci0 power on
go run main.go service server --adapterID hci0

Service is exposed and I can see the descriptor in d-feet.

I will spend more time on it, any help is appreciated Thanks

[freedreamer82]

I can try... but with python it works well on dbus and 5.50 so I guess it's not an bluez issue.

M.

[freedreamer82]

/org/bluez/hci0/apps/app0/service_000003e8/char0/descr0

for instance this is NOT exposed on dbus...

[muka]

Thank you @freedreamer82! You are right, chars and descr where not exposed in the ObjectManager.

We have made a step forward but still I cannot see the list of chars / descr..

There is an error in the logs that I am investigating

bluetoothd[13557]: profiles/gap/gas.c:handle_characteristic() Unsupported characteristic: 00002aa6-0000-1000-8000-00805f9b34fb

As usual, suggestion are welcome!

[freedreamer82]

I tried 2 debug. First of all you need a conf file in /etc/dbus-1/system.d/go-bluetooth.conf something like this

`<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-BUS Bus
Configuration 1.0//EN" "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">

`

after that there is another problem on Properties.GetAll org.bluez.Adapter1: Method "GetAll" with signature "s" on interface "org.freedesktop.DBus.Properties" doesn't exist

you're calling method on wrong interfaces

M.

PS sorry but this stupid form does not format correctly

[freedreamer82]

if can help I have a python bluex example running and it exposes

https://kernel.googlesource.com/pub/scm/bluetooth/bluez/+/5.36/test/example-gatt-server └─/org └─/org/bluez └─/org/bluez/example ├─/org/bluez/example/advertisement0 └─/org/bluez/example/service0 ├─/org/bluez/example/service0/char0 └─/org/bluez/example/service0/char1

so i guess you can use bluez interface without running yours

[muka]

Hi @freedreamer82, the repository has example dbus configuration in ./env/dbus and the install procedure is in the readme.

I used to use the org.bluez namespace but it seemed to interfer with dbus-send, with the latest push the interfaces are also browsable via d-feet so I do not think the problem is there.

Update: In the last commit the UUID is exposed so that it can be configured. Finally the char and descr showed up :tada:

[freedreamer82]

sorry didn't see but I already have them. BTW same error... moreover also your makefile doesn't work on master cd src/bluez && git fetch && git checkout 5.50 error: pathspec '5.50' did not match any file(s) known to git make: *** [Makefile:23: bluez/checkout] Error 1

[muka]

Ok right, it misses the bluez submodule make bluez/init.

I have used BLE Scanner on my phone and it allow me to R/W char and descriptors. Can you share details of your setup (server code / client)?

Thanks

[freedreamer82]

so .. I removed the folder ..cloned it again..installed with the submodule...it goes ok.installed the conf file with the script but

go run main.go service server --adapterID hci0 TRAC[0000] Exec: btmgmt [--index hci0 power off]
TRAC[0000] Exec: btmgmt [--index hci0 le on]
TRAC[0000] Exec: btmgmt [--index hci0 bredr off]
TRAC[0000] Exec: btmgmt [--index hci0 power on]
ERRO[0000] Error: Connection ":1.2314" is not allowed to own the service "go.bluetooth" due to security policies in the configuration file exit status 1

ubuntu machine with bluez 5.50

[muka]

Seems the dbus policies are not enforced. I would check

1. the two files/symlink exists ls /etc/dbus-1/system.d/dbus-go-bluetooth-*
2. dbus policies has been loaded by the daemon make dev/dbus/reload source
3. Your user has the bluetooth group make docker/bluetoothd/init source
4. [In doubt, reboot the machine to apply above updates]

This reflect my own setup on ubuntu 19.10

[freedreamer82]

ok , after a reboot it works :) thanks! I can close it

[muka]

thank you for the help

[mattwallington]

Nice work!

[aykevl]

This error should now be fixed with #105, without requiring any system configuration changes:

Connection ":1.2314" is not allowed to own the service "go.bluetooth" due to security policies in the configuration file