Testers invited to try out new version of the MQTT blocks

Advanced Topics Mods & Extensions
1

I maintain the MQTT library extension and I've made a few changes in my dev enviroment

  1. If you publish a list to a topic- it is sent to the broker as JSON (always has been). But now , if you subscribe to the same topic , the extension detects that the payload is JSON and automatically converts it back to a Snap! list

  2. In current version, you can set subscribe option 1 to true and the payload will be returned as binary byte data but presented as a text string. But now, if you set option 1 to true, it will be returned as a list of values in the range 0-255

  3. Publish has a 3rd option - if set to true, then the payload should be a single column list of values in range or 0-255 (i.e. byte values) and will be sent as a buffer instead of a text string. This then matches up with point 2 above

My test site is at
https://cymplecy.gitlab.io/Snap/snap.html
It doesn't have access to the Snap! cloud so any projects will have to be saved/loaded from your own computer/network

2

Ad.1 I've got the same results (a list)
untitled script pic - 2023-10-17T013410.938
untitled script pic - 2023-10-17T013404.758

So it works as intended.

2,3 is unclear.
I've got the byte array without any extra parameters
untitled script pic - 2023-10-17T021847.660

3

Thanks for testing :slight_smile:

The buffer option sets whether the payload list is published as JSON or as a series of bytes

So this
mqttTutorial script pic (1)

ends up as JSON, length 73

image
image780×282 8.96 KB

whereas this
mqttTutorial script pic (3)

ends up on the broker as just 10 bytes

image
image716×290 9.28 KB

Node-RED used to show the difference