New monitor proposed "HTTP(s) - JSON Custom Function"

[alexmaurer-madis]

⚠️ Please verify that this feature request has NOT been suggested before.

• I checked and didn't find similar feature request

🏷️ Feature Request Type

New Monitor

🔖 Feature description

Some services require more complex checks of the response than a simple KEYWORD or REGEX to perform the validation "Status UP" or "Status DOWN".

It would be awesome to be able to allow custom Javascript code to be run against a parsed JSON Object from an HTTP(s) response.

• The parsed JSON Object could be accessible from the custom JavaScript code as a variable named "msg" for example.
• The custom Javascript code must return true or false or an array for more precise result.

✔️ Solution

This could be achieved by the creation of a new Monitor "HTTP(s) JSON Custom Function" derived from the "HTTP(s) - Keyword".

In the UI a new text zone to write the custom JavaScript code.

❓ Alternatives

No response

📝 Additional Context

This idea is inspired from the node-red "Function" node

Take for example the following simplified JSON response we typically encounter with the Syncthing API GET /rest/system/status

{
    "connectionServiceStatus":{
        "tcp://0.0.0.0:22000":{
            "error":null
        },
        "dynamic+https://relays.syncthing.net/endpoint":{
            "error":null
        }
    },
    "discoveryStatus":{
        "IPv4 local":{
            "error":null
        },
        "IPv6 local":{
            "error":null
        }
    }
}

connectionServiceStatus and discoveryStatus can contain multiple error fields to check and this could be easily achieved with custom Javascript code.