Get path from jsonobject

[Findus76]

Hello

Writes a function to check incoming json against own protocol.
The protocol must contain certain keys, eg "Info", "R / W", "Settings", etc.
For example, the json message may look like this.
{ "Type": "SystemFunction", "Function list": { "Slot 1": { "Settings": {}, "Info": { "Position": "Mobile", "Description": "1,5V max 4A, A, AA, AAA", "Battery Type": "", "Battery ID": 0, "State": "", "Time(s)": 0}, "Voltage":{ "Head Type": "Sensor", "Sub Type": "Voltage", "R/W": "R", "Unit": "V", "Value": 0}, "Current":{ "Head Type": "Sensor", "Sub Type": "Voltage", "R/W": "R", "Unit": "A", "Value": 0}, "Total Charge":{ "Head Type": "Sensor", "Sub Type": "Ampere hour", "R/W": "R", "Unit": "mAh", "Value": 0}, "Total Discharge":{ "Head Type": "Sensor", "Sub Type": "Ampere hour", "R/W": "R", "Unit": "mAh", "Value": 0}}}}

I would like to write a function that takes arguments jsonobject.
For example (above), reference to key "Voltage". If that function sees that key "R / W" is missing, I would like to print an error message "Key: "R / W" is missing under \ Function list \ Slot 1 \ Voltage ".
I dont find any way to find the path from a jsonobject.

Brg

[bblanchon]

Hi @Findus76,

Given a JsonDocument and a JsonObject, there is no way to get the "path" to the JsonObject in the JsonDocument.
In fact, there is no notion of "path" in ArduinoJson.
There is a feature request for a JSONPath resolution (#821), but it's not implemented yet, and it would only go forward.

To work around this limitation, you'll have to handle the path in your program: use a string to remember which path you followed to get to this JsonObject.

Best regards,
Benoit

[Findus76]

Hi Benoit

Thanks.

I will handle it in my program.

Brg