Re: Mqtt support in guile?

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
>>>
>>>
>>>
>>>
>>>
>
>