Re: Mqtt support in guile?

BTW,

I did:

(mosquitto_message_callback_set mosq (procedure->pointer void
receive-message (list '* '* '*)))

Is it correct to pass '* as argument type for the struct mosquitto_message
pointer (3rd arg)?

On Fri, Nov 1, 2024 at 4:08 PM Mikael Djurfeldt <[email protected]>
wrote:

> Thanks!
>
> Doing the (make-cdata struct-mosquitto_message* message) as well as
> changing cdata-ref to cdata*-ref works fine.
>
> Obviously, what someone should do is to write a nice schemey interface on
> top of what you get with (ffi mosquitto).
>
> Best regards,
> Mikael
>
> On Fri, Nov 1, 2024 at 3:05 PM Matt Wette <[email protected]> wrote:
>
>> And one more thing.   There is a manual for cdata.  There is a link on
>> this page
>>
>> https://www.nongnu.org/nyacc/
>>
>>
>> On 11/1/24 6:37 AM, Matt Wette wrote:
>> > I got this wrong.  Sorry!   This is it.  What I gave previously was
>> > the old fh syntax.
>> >
>> > (msg (make-cdata struct-mosquitto_message* message))
>> >
>> >
>> >
>> > On 11/1/24 6:32 AM, Matt Wette wrote:
>> >> assuming message is a Guile pointer:
>> >>
>> >> (define (receive-message mosq obj message)
>> >>   (let ((msg (make-struct-mosquitto_message* message))
>> >>           (size (cdata-ref msg '* 'payloadsize))
>> >>          (payload (cdata-ref msg '* 'payload))
>> >>   (pointer->string payload size)))
>> >>
>> >>
>> >> On 10/31/24 4:49 PM, Mikael Djurfeldt wrote:
>> >>> Hi Matt,
>> >>>
>> >>> This is very nice indeed! :-)
>> >>>
>> >>> I got a small client working, but I found the unpacking of values in
>> >>> the message callback function a bit cumbersome.  I now have:
>> >>>
>> >>> (define (pointer->struct-mosquitto_message pointer)
>> >>>   (let* ((size (ctype-size struct-mosquitto_message))
>> >>>          (bvec (pointer->bytevector pointer size)))
>> >>>          (Xcdata-ref bvec 0 struct-mosquitto_message))) ;The only
>> >>> way I found that worked! :)
>> >>>
>> >>> (define (receive-message mosq obj message)
>> >>>   (let* ((message (pointer->struct-mosquitto_message message))
>> >>>          (payload (cdata-ref message 'payload))
>> >>>          (size (cdata-ref message 'payloadlen))
>> >>>          (payload (pointer->string payload size)))
>> >>>     (display payload)
>> >>>     (newline)))
>> >>>
>> >>> Is there some more convenient/right way to do that?
>> >>>
>> >>> Best regards,
>> >>> Mikael
>> >>>
>> >>> On Thu, Oct 31, 2024 at 1:02 PM Matt Wette <[email protected]>
>> >>> wrote:
>> >>>
>> >>>     On 10/31/24 1:48 AM, Ricardo G. Herdt wrote:
>> >>>     > Hi,
>> >>>     >
>> >>>     > never did it myself, but you can create some bindings to
>> >>>     libmosquitto
>> >>>     > for your usecase. There are bindings for chicken, one can take
>> >>> some
>> >>>     > inspiration from there:
>> >>>     http://wiki.call-cc.org/eggref/5/mosquitto#api
>> >>>     >
>> >>>     > Regards,
>> >>>     >
>> >>>     > Ricardo
>> >>>     >
>> >>>     > Am 31.10.2024 03:24 schrieb Alan Wedel:
>> >>>     >> I have been working on a controller that uses a
>> >>> microcontroller to
>> >>>     >> read some sensors and publish their data to a mqtt broker. I
>> >>> would
>> >>>     >> like to have a guile program subscribe to the mqtt broker and
>> >>>     log the
>> >>>     >> sensor readings to a file. Is there anyone using guile with
>> >>>     mqtt like
>> >>>     >> this? If so, how are you doing it?
>> >>>     >
>> >>>
>> >>>     Here is a dot-ffi file for mosquitto using nyacc:
>> >>>
>> >>>        (define-ffi-module (ffi mosquitto)
>> >>>          #:pkg-config "libmosquitto"
>> >>>          #:include '("mosquitto.h"))
>> >>>
>> >>>
>> >>>     I just uploaded nyacc-2.01.2, needed to compile above.
>> >>>
>> >>>     refs:
>> >>>     https://savannah.nongnu.org/projects/nyacc
>> >>>     https://www.nongnu.org/nyacc/nyacc-fh-ug.html
>> >>>
>> >>>     Matt
>> >>>
>> >>>
>> >>>
>> >>>
>> >>>
>> >
>> >
>>
>>