jsonpath.md

JSONPath-plus

As of version 2.1 of the module it is possible to parse the MQTT messages as JSON and select single values of the JSON with JSONPath-Plus.

⚠️ If the MQTT message is not a valid JSON the parsing will fail and so does the JSONPath-Plus selection. As a result the raw message will be further processed!

You can define the jsonpath option for mqttPayload elements in the mqttDictionary.js like in the following example:

    {
        mqttTopic: "test/test1",
        mqttPayload: [
            {
                jsonpath: "output",
                mqttNotiCmd: ["Command 0"]
            },
            {
                jsonpath: "output2",
                mqttNotiCmd: ["Command 1"]
                payloadValue: '{"state": "ON"}',
            },
            {
                jsonpath: "output2",
                mqttNotiCmd: ["Command 2"]
                payloadValue: '{"state": "OFF"}',
            },
        ],
    },

Lets assume the message looks like:

{
    "output": 10.1,
    "output2": {
        "state": "OFF"
    }
}

With the above configuration this will be the result:

• The messages of the topic test/test1 will be processed
• Command 0 will be called with 10.1 cause no payloadValue is specified to compare the value to
• Command 1 will NOT be called as the value of output2 is {"state": "OFF"}
• Command 2 will be called as the value of output2 is {"state": "OFF"}

Lets look at a second example...

The configuration is:

    {
        mqttTopic: "test/test1",
        mqttPayload: [
            {
                jsonpath: "output.myValue",
                mqttNotiCmd: ["Command 0"]
            },
        ],
    },

Lets assume the message looks like:

{
    "output": {
        "myValue": 10.1,
    },
    "output2": {
        "state": "OFF"
    }
}

The result will be:

• The messages of the topic test/test1 will be processed
• Command 0 will be called with 10.1 cause no payloadValue is specified to compare the value to

For the full power of the selection mechanism please look at the JSONPath-Plus page.