Hi Tony, > On Fri, Apr 17, 2015 at 9:00 PM, Tony DiCola <tony@xxxxxxxxxxxxxx> wrote: > On Fri, Apr 17, 2015 at 12:04 PM, Tony DiCola <tony@xxxxxxxxxxxxxx> wrote: >> Hi all, I'm using bluez 5.3's dbus API (also running bluetoothd with >> the --experimental option) and wanted to check is it possible to >> connect to a BLE device and discover its GATT services without pairing >> to the device? >> >> I'm using the dbus APIs and see that the device Pair() function docs >> call out that it will perform GATT service discovery. This matches >> what I see in practice--when I turn on an adapter's discovery with >> StartDiscovery() I start to see nearby BLE devices added to the bluez >> dbus root (with the org.bluez.Device1 interface). I can connect to >> those devices, but only when I call the device Pair() function do I >> see all the GATT services, characteristics, descriptors, etc. added to >> the bluez dbus root (using the org.bluez.GattService1, >> org.bluez.GattCharacteristic1, etc. interfaces). >> >> However using just the dbus interface is it possible to trigger the >> discovery of all those GATT service, characteristic, etc. objects >> without pairing with a device? I.e. is there an explicit GATT service >> discovery command for a connected device? >> >> Let me know if the question isn't clear, and thanks for any help foks >> can provide. >> >> -Tony > > Just to follow up and close the loop, I went back and realized I > actually am getting all the GATT services, characteristics, etc. > without pairing. I must have had an issue with what I was trying > earlier and see now after just a device connect call the GATT > information shows up a short while after connecting. > > One quick question, is there any easy way to check if a device has > finished its service discovery? Right now I can watch the bluez > ObjectManager's InterfacesAdded signal to see exactly when GATT > objects are created, or even just poll the bluez dbus object hiearchy > for their existance. Just curious if there's a more explicit way like > a signal or changed property to know when a device's service discovery > completes. Thanks! > It's pretty straightforward to know when all the attributes of an individual service have been discovered; basically, once all the GattCharacteristic1 objects under a service have been exported, the "Characteristics" property of the service (GattService1) will be updated and you'll receive a PropertiesChanged signal for it. Finding out that the complete list of services have been discovered and the objects have been exported is a bit trickier. Usually, the "UUIDs" property on org.bluez.Device1 will be populated before a connection with services obtained via advertising/inquiry. Upon connection and when GATT/SDP service discovery has completed (and after the service objects have been exported), the UUIDs property will update with the full list of services. Here you could do something like tracking InterfacesAdded signals and comparing the newly added services to the initial UUID list. I would be open to adding a signal/property to notify applications when service discovery completes though this hasn't really been an issue so far. Usually applications can be built in a very event based manner and update their state on a per-service basis as service hierarchies get added and removed. I hope this helps! Arman -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
