DSL Rule DateTime formatting?

[nikagl (Nika Gerson Lohman)]

I have the output of an API in json in which dates are associated to prices. I am parsing the dates but trying to format them, but I get the following error:
An error occurred during the script execution: Could not invoke method: org.openhab.core.library.types.DateTimeType.format(java.lang.String) on instance: 2022-12-27T00:00:00.000+01:00

My code is the following:

rule "Testing date conversion"
when
    Time cron "0 30 15 1/1 * ? *"
then
	var String response_json = ""
	var int hour
	var DateTimeType startsAt
	var Number total
	
	response_json = pricesfortoday.state.toString()
	logInfo("TestDateConvert", "response_json = {} from API, length {}", response_json, response_json.length())

	for (hour=0; hour < 24; hour++) {
		logInfo("TestDateConvert", "hour = {}", hour)
		startsAt = transform("JSONPATH", "$[" + hour + "].startsAt", response_json)
		total = transform("JSONPATH", "$[" + hour + "].total", response_json)

		logInfo("TestDateConvert", "startsAt = {}", startsAt)
		logInfo("TestDateConvert", "total = {}", total)
		
		val String MyStringFromDateTimeType = startsAt.format("%1$td.%1$tm.%1$ty %1$tH:%1$tM")
		logInfo("TestDateConvert", "MyStringFromDateTimeType = {}", MyStringFromDateTimeType)
	}
end

The full log results:

2022-12-26 23:52:35.588 [INFO ] [ab.core.model.script.TestDateConvert] - response_json = [{"startsAt":"2022-12-27T00:00:00.000+01:00","total":0.1213},{"startsAt":"2022-12-27T01:00:00.000+01:00","total":0.0906},{"startsAt":"2022-12-27T02:00:00.000+01:00","total":0.0859},{"startsAt":"2022-12-27T03:00:00.000+01:00","total":0.0842},{"startsAt":"2022-12-27T04:00:00.000+01:00","total":0.1115},{"startsAt":"2022-12-27T05:00:00.000+01:00","total":0.13},{"startsAt":"2022-12-27T06:00:00.000+01:00","total":0.2063},{"startsAt":"2022-12-27T07:00:00.000+01:00","total":0.3055},{"startsAt":"2022-12-27T08:00:00.000+01:00","total":0.2913},{"startsAt":"2022-12-27T09:00:00.000+01:00","total":0.3456},{"startsAt":"2022-12-27T10:00:00.000+01:00","total":0.3324},{"startsAt":"2022-12-27T11:00:00.000+01:00","total":0.2709},{"startsAt":"2022-12-27T12:00:00.000+01:00","total":0.2614},{"startsAt":"2022-12-27T13:00:00.000+01:00","total":0.2173},{"startsAt":"2022-12-27T14:00:00.000+01:00","total":0.2271},{"startsAt":"2022-12-27T15:00:00.000+01:00","total":0.2317},{"startsAt":"2022-12-27T16:00:00.000+01:00","total":0.2364},{"startsAt":"2022-12-27T17:00:00.000+01:00","total":0.2485},{"startsAt":"2022-12-27T18:00:00.000+01:00","total":0.255},{"startsAt":"2022-12-27T19:00:00.000+01:00","total":0.2467},{"startsAt":"2022-12-27T20:00:00.000+01:00","total":0.2364},{"startsAt":"2022-12-27T21:00:00.000+01:00","total":0.2159},{"startsAt":"2022-12-27T22:00:00.000+01:00","total":0.1931},{"startsAt":"2022-12-27T23:00:00.000+01:00","total":0.1703}] from API, length 1438
2022-12-26 23:52:35.588 [INFO ] [ab.core.model.script.TestDateConvert] - hour = 0
2022-12-26 23:52:35.589 [INFO ] [ab.core.model.script.TestDateConvert] - startsAt = 2022-12-27T00:00:00.000+01:00
2022-12-26 23:52:35.589 [INFO ] [ab.core.model.script.TestDateConvert] - total = 0.1213
2022-12-26 23:52:35.590 [ERROR] [internal.handler.ScriptActionHandler] - Script execution of rule with UID 'power_price-2' failed: An error occurred during the script execution: Could not invoke method: org.openhab.core.library.types.DateTimeType.format(java.lang.String) on instance: 2022-12-27T00:00:00.000+01:00 in power_price

Any thoughts?

[rlkoshak (Rich Koshak)]

This is not a JavaScript rule so your thread title is a bit confusing.

@nikagl

"%1$td.%1$tm.%1$ty %1$tH:%1$tM"

These formatting require a ZonedDateTime to work on. All you have is a String. Luckily it’s in ISO8601 format so you should be able to simply pass it to a ZonedDateTime.

val startsAtDT = ZonedDateTime.parse(startsAt, DateTimeFormatter.ISO_OFFSET_DATE_TIME)
logInfo("TestDateConvert", "ZonedDateTime from String Formatted = {%1$td.%1$tm.%1$ty %1$tH:%1$tM}", startsAtDT)-

[nikagl (Nika Gerson Lohman)]

Well… I have added:

	val startsAtDT = ZonedDateTime.parse(startsAt, DateTimeFormatter.ISO_OFFSET_DATE_TIME)
	logInfo("TestDateConvert", "ZonedDateTime from String Formatted = {%1$td.%1$tm.%1$ty %1$tH:%1$tM}", startsAtDT)

But that doesn’t work either:

2022-12-29 09:44:24.341 [INFO ] [ab.core.model.script.TestDateConvert] - startsAt = 2022-12-29T23:00:00.000+01:00
2022-12-29 09:44:24.341 [INFO ] [ab.core.model.script.TestDateConvert] - total = 0.1155
2022-12-29 09:44:24.341 [INFO ] [ab.core.model.script.TestDateConvert] - ZonedDateTime from String Formatted = {%1$td.%1$tm.%1$ty %1$tH:%1$tM}

I have then added the format to the variable:

		val startsAtDT = ZonedDateTime.parse(startsAt, DateTimeFormatter.ISO_OFFSET_DATE_TIME)
		logInfo("TestDateConvert", "ZonedDateTime from String Formatted = {}", startsAtDT.format("%1$td.%1$tm.%1$ty %1$tH:%1$tM"))

Same issue as before, but now with java.time.ZonedDateTime.format(java.time.format.DateTimeFormatter):

2022-12-29 09:48:20.504 [INFO ] [ab.core.model.script.TestDateConvert] - startsAt = 2022-12-29T00:00:00.000+01:00
2022-12-29 09:48:20.504 [INFO ] [ab.core.model.script.TestDateConvert] - total = 0.0746
2022-12-29 09:48:20.506 [ERROR] [internal.handler.ScriptActionHandler] - Script execution of rule with UID 'power_price-2' failed: An error occurred during the script execution: Could not invoke method: java.time.ZonedDateTime.format(java.time.format.DateTimeFormatter) on instance: 2022-12-29T00:00+01:00 in power_price

Note that I did try every option mentioned here, but still couldn’t figure it out:

DateTime Conversion (openHAB 3.x)

Because openHAB 2.x rules use Jodatime instead of Java Time API, there is still the old DateTime Conversion thread for openHAB 2.x. Overview In openHab 3.x there are different ways to handle Date/Time values. DateTimeType A DateTime Item carries a DateTimeType. Java Time By default openHAB 3.x Rules DSL use java.time API to represent date and time. Principle java date-time concepts are LocalDateTime (date and time without any offset or time-zone) and ZonedDateTime (“full” date-time wit…

Regards,

Nika.

[Chiuaua79 (Cor)]

In the top of your rule, shouldn’t you declare

var DateTimeType startsAt

as

var String startsAt

Then in your “for”-loop (after you have extracted the JSON for “startsAt”):

val DateTimeType startsAtDT = DateTimeType.valueOf(startsAt)

and change

val String MyStringFromDateTimeType = startsAt.format("%1$td.%1$tm.%1$ty %1$tH:%1$tM")

to

val String MyStringFromDateTimeType = startsAtDT.format("%1$td.%1$tm.%1$ty %1$tH:%1$tM")

Had a similar issue a couple of weeks back. Had to convert from java time (now) to DateTimeType, before I could convert to day of the week with .format(“%1$tA”)

[nikagl (Nika Gerson Lohman)]

Yes, thanks Rich and Cor for this, it works as a charm after defining & converting it from String to DT and back