How can I pick a value out of a JSON String

Setup, Configuration and Use Beginners
1
  • Platform information: Pi4 Habian 2.5.3

I get updates from Blue Iris (Cameras) each time the profile is changed. I was able use a REST item to display the setting on the HABPanel. However, like a few other devices the OH server gets resarted from time to time and I’d like to have OH request the profile setting on startup.

rule "Startup"
when
//    testing assistant - this will be replaced with on start
    Time cron "0 0/1 * 1/1 * ? *"
then
    biProfileReturn_json.postUpdate(sendHttpGetRequest("http://192.168.1.6:31793/admin?&user=xyw&pw=123"))
    val newValue = transform("JSONPATH", "signal.profile", biProfileReturn_json.state.toString)
    //post the new value to the Number Item
    biProfile.postUpdate( newValue )
    logInfo("Bi", "one more minute")
end

The Get returns
signal=green
profile=6
lock=1

I want to pick that 6 or whatever number is returned out and replace biProfile

I also see in the doc https://www.openhab.org/addons/transformations/jsonpath/ that If the JsonPath expression provided results in no matches, the transformation will return the entire original JSON string which is my case.

I did also try

val newValue = transform("JSONPATH", "signal.profile.lock", biProfileReturn_json.state.toString)

Thanks for a pointer to learn about JSON or a quick fix

2

That’s not JSON, it’s just key-value pairs.

I think you could extract your value with REGEX, but I don’t know how exactly.

3

Thanks - I just read the log literally instead of looking at it. The error specifically say JSONPATH not available. I thought o-yah I recall regex was an add on and sure enough it looks like all transformations are not loaded by defualt.

4

Yep, you would have to install JSONPATH. It helps to share error messages.

It still won’t work on nearly-JSON though :wink:

5

Yes - It may just not be the day to do this. Maybe tomorrow!
Thank you for the help

6

For the line in your rule, try this:

    biProfileReturn_json.postUpdate(sendHttpGetRequest("http://192.168.1.6:31793/admin?&user=xyw&pw=123:60000:REGEX((.*))"))

I had add the “:60000:REGEX((.*))” to the transform for a very long JSON file to pull out the one piece of data that I was looking for. Hope this helps!

~John

7

Thanks John - I did a little playing around and ended up with val newval = transform(“REGEX”, “.profile=(\d).”, biProfileReturnstr.state.toString). In my case the string was within whatever the standard length that regex cosiders and the profile= made it easy to define. Hopefully I remember that option when I encounter a really long string. That isn’t something I would have expected to need to do but appreciate knowing