Parse JOSN received via Particle.function

Firmware
1

Hi All,

I’m a little rusty, apologies to whom find this an easy question.

My goal; parse a JSON received via Particle.function and call a function based on the value of the key named “type”.

Example JSON: {"event":{"id":444,"attributes":{},"deviceId":1,"type":"connected"}}

What I have as code:


int handleJsonCommand(String arg) {

    // Parse incoming JSON
    JSONValue root = JSONValue::parseCopy(arg);
    if (!root.isObject()) return -1;

    // First: iterate root to find "event"
    JSONValue eventObj;
    {
        JSONObjectIterator it(root);
        while (it.next()) {
            if (it.name() == "event") {
                eventObj = it.value();
            }
        }
    }

    if (!eventObj.isObject()) return -2;

    // Now iterate "event" object to find "type"
    String typeStr = "";

    JSONObjectIterator itEvent(eventObj);
    while (itEvent.next()) {
        if (itEvent.name() == "type") {
            if (itEvent.value().isString()) {
                typeStr = itEvent.value().toString();
            }
        }
    }

    if (typeStr.length() == 0) return -3;

    Particle.publish("eventType", typeStr, PRIVATE);

    return 1;

}

The error I receive on build:

no match for 'operator=' (operand types are 'String' and 'spark::JSONString')
Pointing to this line: typeStr = itEvent.value().toString();

Any command is appreciated that achieves the goal of extracting the value out of key “event”.

2

This should work:

typeStr = itEvent.value().toString().data();
2 Likes
3

that worked, much appreciated!