Adding external sensors OTA

[LeSuedois]

estimate: 5d

Steps to reproduce

• COOL Board with plugged in external sensor
• Do no configure external sensors when flashing SPIFFS
• Prepare an MQTT message to add an external sensor with "state": { "desired": { ... }}

Actual

• External sensor is not added or configuration messed up ❌

Expected

• It works ✔️

Hints

• Incremental update or full overwrite?

Background

@simon-lacool

I tried to add a external sensor (NDIR CO2 sensor) over the air and it failed... the I tried all kinds of figures, sending just the config for new sensor, sending everything.
The configuration is arriving partially in the configuration and the new sensor didn't work. after flashing the howl stuff tu the SPIFFS everything worked nice.

[LeSuedois]

In fact the problem is slightly more global than that. It has to do with the REST API and the fact that we only get the difference between reported and desired.
Example:
shadow state:
{"val1"=1, "val2"=2, "val3"=3}
json from user:
{"val1"=2, "val2"=2, "val3"=1}
json in desired channel
{"val1"=2, "val3"=1}
json in memory after update
{"val1"=2, "val3"=1}

the REST API acts as intended but the coolboard does not keep unchanged values. "that's all"...

[LeSuedois]

merge acbb2c3 is related to this issue, I put in to needs testing...

[3rwww1]

To review / define

[LeSuedois]

Just a other try to document this a little more..
let's change a parameter on Act5, the original configuration was
{ "state":{ "desired":{ "jetPack":{ "Act5":{ "actif":1, "inverted":0, "temporal":1, "low":[1500,0,0,0], "high":[1700,0,0,0], "type":["CO2",""] } } } } }
but the inverted flag was wrong... (the fan on Act5 goes on and CO2 falls)
After many trys I sent this:
{ "state":{ "desired":{ "jetPack":{ "Act5":{ "actif":null, "inverted":null, "temporal":null, "low":[null,null,null,null], "high":[null,null,null,null], "type":[null,null] } } } } }
but when I look at the shadow I am still not happy:
... "jetPack": { "Act5": { "low": [ null, null, null, null ], "high": [ null, null, null, null ], "type": [ null, null ], "actif": 1, "inverted": 1, "temporal": 0 } ...
so IMO the right way (but not very handy though) is to send null for all arrays and send something like (pseudocode) "active" = !active; "inverted" = !inverted; .... once received we send the real config.
in my case:
{ "state":{ "desired":{ "jetPack":{ "Act5":{ "actif":0, "inverted":0, "temporal":1, "low":[null,null,null,null], "high":[null,null,null,null], "type":[null,null] } } } } }
and then:
{ "state":{ "desired":{ "jetPack":{ "Act5":{ "actif":1, "inverted":1, "temporal":0, "low":[1500,0,0,0], "high":[1700,0,0,0], "type":["CO2",""] } } } } }
only then it works..