Re: Mqtt support in guile?

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
>
>
>
>
>