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marting's avatar
marting
Icon for Neophyte rankNeophyte
2 years ago
Solved

JSON Path capability in a Webpage DataSource

I think the answer to this is gonna be “You need to script it, dummy”, but figured I’d check anyway...

I'm working on a new DataSource that pulls/interprets JSON data from a peudo-custom system via HTTP.

The system has a status page that lists the status of various components using JSON elements that have this general format:

ParameterName&ParameterType

Initial idea was that I could use the Webpage collector since it supports JSON/BSON parsing.

Issue I’m running into is that the values on most of these JSON elements are string (i.e. “true”/”false”).

I set up a DataPoint that can extract that value by putting in the JSON Path like so:

$.[##WILDVALUE##].[ParameterName&ParameterType]

...and I can see that I’m getting the “true”/”false” values back when I do a Poll Now.  But - as we know - LM won’t deal with strings natively.

Workaround I came up with was to get length of the string since true/false are different lenghts.

According to sources online, JSON Path should support a calculation of string length.

I've also verified that I can do this by pasting my data and my JSON Path expression:

$.[ComponentName].[ParameterName&ParameterType].length

...into https://jsonpath.com/

In this parser, the .length function works as expected, and returns the length of the JSON value.

However, in LogicMonitor, I'm just getting this (example failure):

NAN after processing with json
(postProcessParam: $.[ComponentName].[ParameterName&ParameterType].length, reference=, useValue=body)

Anyone know if there is a way to make this JSON Path length function work?

  • Anonymous's avatar
    Anonymous
    2 years ago

    There’s an easier way than this:

    function parseBooleanValue(value) {
      if (value === 'true') {
        return 1;
      } else if (value === 'false') {
        return 0;
      } else {
        return null; // or throw an error, depending on how you want to handle invalid values
      }
    }

    It uses the ternary operator:

    (value == "true") ? 1 : 0

    This is exactly equivalent to:

    if (value == "true") {
      return 1
    } else {
      return 0
    }

    No need for a function at all, it’s overkill.