valueFormat.md

valueFormat

As of version 2.1 of the module it is possible to format the MQTT messages or notification payloads before they get further processed.

ℹ️ The MQTT message or notification payload will be in the variable value which you can access in the valueFormat with ${value}.

⚠️ As formatting of newlines causes problems you need to configure a newlineReplacement either in the global module configuration or in the configuration of the messages/payloads.

You can define the valueFormat option for mqttPayload elements in the mqttDictionary.js or in the elments of notiPayload in notiDictionary.js like in the following examples:

    notiPayload: [
        {
            newlineReplacement: "#",
            valueFormat: "\"${value}\".replace(\"test\",\"\").replace(\"abc\",\"\")",
            notiMqttCmd: ["Command 0"],
        }
    ]

    mqttPayload: [
        {
            valueFormat: "Number(${value}).toFixed(2)",
            mqttNotiCmd: ["Command 0"]
        },
    ],

Let's look at some examples now.

Let us assume we do have the following notification configuration:

    notiPayload: [
        {
            valueFormat: "Number(${value}).toFixed(2)",
            notiMqttCmd: ["Command 0"],
        }
    ]

Now we receive the corresponding notification with the payload:

10.123456

The result will be:

• The command Command 0 will be called with the value 10.12.

Now lets assume we do have the configuration:

    notiPayload: [
        {
            valueFormat: "Number(${value.output}).toFixed(2)",
            notiMqttCmd: ["Command 0"],
        }
    ]

And the notification payload is:

{
    output: 10.12345
}

The result will be the same as before as we selected ${value.output} in the configuration.

Now lets assume the following configuration:

    notiPayload: [
        {
            newlineReplacement: "#",
            valueFormat: "\"${value}\".replace(\"test\",\"\").replace(\"abc\",\"\").replace(\"#\",\"\")",
            notiMqttCmd: ["Command 0"],
        }
    ]

And the notification payload is the following string with new line characters:

test
123
abc

As newline charcters will be replaced with # and then test, abc and # will be replaced by nothing the result will be 123.

The way to format MQTT messages is the same as for the notification payload but if you want to select sub elements like output in the example before you need to use the jsonpath option first. See jsonpath.md for more details but let us look at a simple example now.

The MQTT configuration contains:

    mqttPayload: [
        {
          jsonpath: "output",
          valueFormat: "Number(${value}).toFixed(2)",
          mqttNotiCmd: ["Command 0"]
        },
    ],

The received MQTT message is:

{
    "output": 10.12345
}

And again the result will be the same as in the notification example. The Command 0 will be called with value 10.12.

Further examples

valueFormat: ""${value}".replace("test","").replace("abc","")"

The value will be interpreted as strint, test and abc in the string will be replaced with nothing. So if the input will be something like test123abc the result will be 123.

valueFormat: ""${value.myInput}".replace("test","").replace("abc","")"

The myInput of the value will be selected, test and abc will be replaced with nothing. So fi the input is something like {myInput: test123abc} the result will be 123.