JSR223 Jython Scripting Helper

Here I would like to briefly introduce my own openHAB Rule Helper classes. The reason to create them was because of the syntax of the JSR223 Jython interface was too complex and complicated to write a simple Rule.

There is already a GibHub project which offers a high degree of abstraction. This does not go far enough for me, which is why I designed my own solution. However, it is based on the existing solution and extends it.

Example of a simple rule

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@rule("door_bell_notification.py")
class DoorBellNotificationRule:
    def __init__(self):
        self.triggers = [ItemStateChangeTrigger("Bell_State", "OPEN")]

    def execute(self, module, input):
        self.log.info(u"Bell was triggered"")
        if itemStateOlderThen("Bell_Last_Change", getNow().minusSeconds(30)):
            sendNotification("Bell", "Bell rings", "https://yourServer.de/cameraStreetImage")
            sendMail("Bell rings", u"Someone rings on the Door", "https://yourServer.de/cameraStreetImage")

        postUpdate("Bell_Last_Change", DateTimeType())

Rule Annotation

The @rule annotation registers this class as a rule. The contained string “door_bell_notification.py” is needed for logging. My Rule Annotation now offers the following enhancements:

Methods

Furthermore, my class offers a variety of useful helper methods. They are based on the functionality of openHAB 1.x and should facilitate the migration to Jython based rules in openHAB 2.x.

Sources

All my used rules are based on this Jython extension. It can be obtained directly from my GitHub Repository.

In addition, the classes from the previously mentioned Jython project still need to be installed. The easiest way is to follow the Jython installation guide and then copy everything from my repository into its openHAB python folder

Burntime Script

Another problem in openHAB was that rules were started before openHAB was completely initialized. To fix this problem I wrote the “burntime” script.

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log = LoggerFactory.getLogger("org.eclipse.smarthome.automation")

log.info("jsr223: checking for initialised context")

while True:
    try:
        scriptExtension.importPreset("RuleSupport")
        # from openhab.jsr223.scope import items
        # if items != None:
        if automationManager is not None:
            break;
    except:
        # instance = sys.exc_info()[1]
        # log.info(str(instance))
        pass
    log.info("jsr223: context not initialised yet. waiting 10 sec before checking again")
    time.sleep(10)

log.info("jsr223: done")

It is stored under the name “000_burntime.py” in the openHAB Rule folder and started first. It now runs until the openHAB “automationManager” is available and blocks the execution of all other rules until then.

This script can also be downloaded from my GitHub repository.

https://github.com/HolgerHees/openhab-config/blob/master/conf/automation/jsr223/000_burntime.py

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