On 11/05/2014 06:47 PM, Arman Uguray wrote:
Hi Edmund,
On Wed, Nov 5, 2014 at 9:21 AM, Urbani, Edmund <edmund.urbani@xxxxxxxxxxxx> wrote:
On 11/04/2014 08:11 PM, Arman Uguray wrote:
Hi Edmund,
On Tue, Nov 4, 2014 at 4:04 AM, Urbani, Edmund
<edmund.urbani@xxxxxxxxxxxx> wrote:
On 11/03/2014 08:32 PM, Arman Uguray wrote:
Hi Edmund,
On Mon, Nov 3, 2014 at 7:38 AM, Urbani, Edmund
<edmund.urbani@xxxxxxxxxxxx> wrote:
Hello all,
I am trying to write a simple GATT-based service of my own. Right now I
don't really know which docs I should be looking at. I have skimmed
through
bluez sources (5.23) and found gatt-service.h and gatt.h, as well as
the
gatt-example plugin.
So far I am still trying to figure out whether I should be going the C
API
route or maybe use the D-Bus interface. Also gatt-service.c seems to
suggest
that there is a way to register a GATT service over D-Bus but running
it
gives me this:
RegisterService: Method "RegisterService" with signature "oa{sv}" on
interface "org.bluez.GattManager1" doesn't exist"
The reason you're not seeing GattManager1 is because it's hidden
behind the "experimental" flag. So you need to configure and run bluez
with the --enable-experimental and the --experimental flags
respectively.
That said, that API implementation isn't complete and isn't in fact
even wired up with the internal attrib-server. We're working towards
rewriting all of the C API and finally implementing the proposed D-Bus
API but until then, I would ignore doc/gatt-api.txt (it's only a
proposal at the moment and isn't even included in release tarballs).
So for now you have to use the C API route. There will probably be an
announcement once that D-Bus API is finally supported.
Any pointers to help me get started would be appreciated. Thanks!
Kind regards,
Edmund
Cheers,
Arman
Thanks, I won't bother with the D-Bus interface then. But if the C API is
being rewritten now, that sounds like there is currently no stable API
available at all. :/ Or is it just the internals being rewritten?
The C API for GATT interactions is being rewritten, i.e. the code in
attrib/* is being deprecated in favor of code in src/shared/gatt*. You
can still keep using the existing APIs though at some point we will
rip out the existing attrib-server to be a combination of
shared/gatt-db and shared/gatt-server. So, make sure you keep track of
the patches going in.
Keep in mind that if you're developing your code on top of the master
branch then things are meant to be in flight and unstable there, so
you should follow releases anyway. I think we'll figure out a way so
that the C based GATT server/client won't be entirely broken for
people in between official BlueZ releases.
So I assume, the fastest route the get a prototype that does something,
would be to get gatt-example.c to run and then modify that, right?
Yes, that is the easiest way right now. When the new C APIs are mature
enough we will convert gatt-example to use the new code but that's
still a few months down the line.
Kind regards,
Edmund
--
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
Cheers,
Arman
Thanks, Arman. I now have a basic service with one characteristic and a
read-only value up and running (I can see and read its value from another
system using gatttool... though my iOS app still fails to discover the
service :/ ).
What I actually need however is a read/write attribute and a way to react to
write requests. The examples in gatt-service.c all seem to be read-only. How
would I get a call-back for an incoming write request?
It's not obvious from reading the existing code but the
"gatt_service_add" function defined attrib/gatt-service.h allows you
to specify read/write handlers using options passed via its variable
length argument list. You can look at profiles/proximity/linkloss.c
for an example of this. Looking at the link_loss_register function, I
see the profile register both a read and a write callback for the
Alert Level characteristic (the functions link_loss_alert_lvl_read and
link_loss_alert_lvl_write). I think this is what you're looking for.
That said, the new API will hopefully make this more readable by doing
away with the variable argument list and having explicit functions and
arguments for inserting characteristics into the database with
read/write handlers.
Kind regards,
Edmund
--
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
Cheers,
Arman
Alright, I have a GATT service up and running with handlers for read and write
requests, and an iOS app that acts as the client/central.
The only thing that is still now working the way it should is service discovery.
Currently the client finds the service by connecting to any device which
advertises itself as connectable and then queries its service UUIDs. Apparently
my service UUID (currently still 16 bit) is not advertised, and so I have to
resort to this kind of slow, battery-consuming service discovery. How do I get
BlueZ to include the service UUID in LE advertisements?
This is the last obstacle to a demo-ready prototype for my project. Thanks for
everything so far!
And as for future development and production use - any guesses when a BlueZ
version with a stable GATT service interface over D-Bus might be released?
Kind regards,
Edmund Urbani
--
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
