Regex string to switch

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1

Hello everyone,
I am trying to check if a String I get from my local weather provider contains a certain word and turn a switch on if this is true and off otherwise.
I initially thought this would be an ideal case for a regEx and I also kind of remembered how to mage a regex that matches the string, but how do I get it to return ON if it matches and OFF if not?
thanks for any advice!

2

What binding? If the HTTP binding, which is what I suspect, you can use a REGEX transformation to extract the part of the string that would contain the word and chain that to a MAP transformation to map the string to ON/OFF.

If there is only two possible values, instead of the MAP transform, you could use the on/off value properties to do the mapping.

Obviously, this could be done in a rule too but it’s not strictly necessary now.

If it’s not the HTTP binding and it’s a binding that doesn’t support chaining transformations, you can apply the REGEX to the Channel and use a Profile to apply the MAP.

You could also apply a SCRIPT transformation to do it all in code instead of chaining transformations. This might be easier because you could use something like (JavaScript):

(function(i) {
  return (i.includes('mystring')) ? 'ON' : 'OFF';
})(input)

But to answer your specific question, you can’t get the REGEX to return ON/OFF. You can only have it return a portion of the string you care about and then you can use that with another transform.

3

Thanks very much! This sounds like a way better approach. Now I have one problem: the binding I am using (DWD warning) outputs undef if there is no warning present. It seems to me the transformation script isn’t even executed. How do I get the transformation to turn the switch off if the thing state is undefined?

Thanks for your help!

4

Use transform profile. That’s gets run between the channel and the Item and you can check for UNDEF there.

5

Thanks a lot!
Got it working by just checking in js for “UNDEF”. The transformation now looks like that:

(function(i) {
    if (i = "UNDEF") return 'OFF';
    return (i.includes('String I want')) ? 'ON' : 'OFF';
  })(input)