Json data to table problem

[bednarekluc]

I have a problem with json data from the MQTT broker.

I receive this string from the MQTT : {"Redox": "954","Ph": "6.67","Temperatuur": "10.5","Error message": ""}
When I check it (https://jsonformatter.curiousconcept.com/#) is valid JSON data.

When i decode this with 
payload = "{"Redox": "954","Ph": "6.67","Temperatuur": "10.5","Error message": ""}"
msg =  json.pdecode(payload)

The result is still a string instead of a table.

I guess i'm missing something obvious.

Can anyone help me?

[admin]

Are you sure you are logging the correct variable - msg instead of payload? If pdecode fails then the msg variable will be nil, not a string.

[bednarekluc]

Yes I’m sure

This is the code

mclient.ON_MESSAGE = function(mid, topic, payload)
local msg = json.pdecode(payload)
log ("Payload", type(payload)

log(type(msg),msg)
log(json.decode(msg).variable)
if type(msg) == 'table' then
Redox = msg.Redox
log("redox",Redox)
end
end

[admin]

It's possible that the payload is encoded twice so you get a string after first decode. Try decoding the msg again and post what you get.

[bednarekluc]

It's possible that the payload is encoded twice so you get a string after first decode. Try decoding the msg again and post what you get.

Indeed it was encoded twice.

Double decode solved it.

local msg = json.pdecode(json.pdecode(payload))

Thank you.