# JSR223 Scripting

# Overview

JSR223 (opens new window) (spec (opens new window)) is a standard scripting API for Java Virtual Machine (JVM) languages (opens new window). The JVM languages provide varying levels of support for the JSR223 API and interoperability with the Java runtime. Currently the following languages are known to work well for openHAB scripting: Apache Groovy (JVM scripting language), JavaScript/ECMA - 262 Edition 5.1, JavaScript/ECMAScript 262 Edition 11, Ruby, and Jython (opens new window) (Python 2.7 on the JVM).

Please note that JavaScript/ECMA - 262 Edition 5.1 which is referenced here is using an older engine called NashornJS. This version of JavaScript/ECMAScript is end of life and lacks many important features that have been added to the language since 2009. If you plan to use JavaScript/ECMAScript as your scripting language, it is recommended to use JavaScript/ECMAScript 262 Edition 11, also known as JS Scripting, which includes the latest ES6 language features, supports third party node libraries (please keep in mind that not all NodeJS APIs are available in GraalJS), and comes with a well documented helper library (openhab-js (opens new window)) that makes interaction with the APIs documented on this page (and more) much simpler and straight forward in plain JavaScript.

Although JSR223 scripts can be used as a general-purpose extension language for openHAB, it is most commonly used for the creation of rules, and within scripted Actions or Conditions. Currently, openHAB allows JSR223 scripting to access all packages, which may not be included in the official APIs. This provides great flexibility for the users of JSR223, but is also use at your own risk, since changes outside of the official APIs occur frequently, and are not considered to be breaking changes. New APIs are planned to be implemented in the future, which will provide standardized interfaces for interacting with openHAB through scripted automation.

# Example rules for a first impression

'use strict';

scriptExtension.importPreset("RuleSupport");
scriptExtension.importPreset("RuleSimple");

var sRule = new SimpleRule() {
    execute: function( module, input) {
        print("This is a 'hello world!' from a JavaScript rule.");
    }
};

sRule.setTriggers([
    TriggerBuilder.create()
        .withId("aTimerTrigger")
        .withTypeUID("timer.GenericCronTrigger")
        .withConfiguration(
            new Configuration({
                "cronExpression": "0 * * * * ?"
            })).build()
    ]);

automationManager.addRule(sRule);

// Import openHAB Java API
Object.assign(this, require('@runtime'));
Object.assign(this, require('@runtime/RuleSimple'));
Object.assign(this, require('@runtime/RuleSupport'));

// Override non-working TriggerBuilder import
const TriggerBuilder = Java.type('org.openhab.core.automation.util.TriggerBuilder');

const sRule = new SimpleRule({
  execute: function(module, input) {
    print('This is a \'hello world!\' from a JavaScript rule.');
  }
});
sRule.setName('A JavaScript/ECMAScript 262 Edition 11')
sRule.setTriggers([
  TriggerBuilder.create()
    .withId('aTimerTrigger')
    .withTypeUID('timer.GenericCronTrigger')
    .withConfiguration(
      new Configuration({
        'cronExpression': '0 * * * * ?'
      }))
    .build()
]);

automationManager.addRule(sRule);

// And the same rule using the helper library:

const { rules, triggers } = require('openhab');

rules.JSRule({
    name: 'A JavaScript/ECMAScript 262 Edition 11',
    description: 'This is a JavaScript rule.',
    triggers: [
        triggers.GenericCronTrigger('0 * * * * ?')
    ],
    execute: (event) => {
        console.log('This is a \'hello world!\' from a JavaScript rule.');
    }
});

scriptExtension.importPreset("RuleSupport")
scriptExtension.importPreset("RuleSimple")

class myRule(SimpleRule):
    def execute(self, module, inputs):
        print "This is a 'hello world!' from Jython rule."

sRule = myRule()
sRule.setTriggers([
    TriggerBuilder.create()
        .withId("aTimerTrigger")
        .withTypeUID("timer.GenericCronTrigger")
        .withConfiguration(
            Configuration({
                "cronExpression": "0 * * * * ?"
            })).build()
    ])

automationManager.addRule(sRule)

import org.openhab.core.automation.*
import org.openhab.core.automation.module.script.rulesupport.shared.simple.*
import org.openhab.core.config.core.Configuration

scriptExtension.importPreset("RuleSupport")
scriptExtension.importPreset("RuleSimple")

def sRule = new SimpleRule() {
    Object execute(Action module, Map<String, ?> inputs) {
        println("Hello World from Groovy")
    }
}
sRule.setTriggers([
    TriggerBuilder.create()
        .withId("aTimerTrigger")
        .withTypeUID("timer.GenericCronTrigger")
        .withConfiguration(new Configuration([cronExpression: "0 * * * * ?"]))
        .build()
    ])

automationManager.addRule(sRule)

$scriptExtension.importPreset('RuleSupport')
$scriptExtension.importPreset('RuleSimple')

class MyRule < SimpleRule
  def execute(_mod, _inputs)
    logger = org.slf4j.LoggerFactory.getLogger('org.openhab.automation.example')
    logger.info('Hello World from JRuby')
  end
end

s_rule = MyRule.new
s_rule.set_triggers([
        TriggerBuilder.create
                      .with_id('aTimerTrigger')
                      .with_type_uid('timer.GenericCronTrigger')
                      .with_configuration(Configuration.new({ 'cronExpression' => '0 * * * * ?' }))
                      .build
    ])

$automationManager.add_rule(s_rule)

# And the same rule using the bundled helper library:

rule "A Cron Rule in Ruby" do
  every :minute
  run do
    logger.info "Hello World from JRuby"
  end
end

# Script Locations

Scripts should be placed in the ${OPENHAB_CONF}/automation/jsr223/ directory. This directory will vary, based on the type of openHAB installation used (opens new window). For example, Linux installations created with a package installer will use /etc/openhab/automation/jsr223/, and manual installations will use /opt/openhab/conf/automation/jsr223/.

When openHAB starts, scripts are loaded at start level 40 by default (in no particular order). The start level for each script can be overridden by specifying a start level either in the filename (./my_script.sl50.py) or containing directory (./sl50/my_script.py). The runtime provides no explicit dependency mechanism or ordering, yet scripts are loaded one at a time so can be ordered via start level if desired. For example, with the following scripts and directory structure...

├── automation/jsr223
│   ├── dir1
│   │   ├── script_a.py
│   │   └── script_b.py
│   ├── script.sl38.py
│   ├── sl30
│   │   ├── script_x.py
│   │   └── script_y.py
│   └── script.py

... the load order will be: (sl30/script_x.py & sl30/script_y.py) at start level 30, script.sl38.py at start level 38, then (/dir1/script_a.py, /dir1/script_b.py, script.py) at start level 40. The script file watching mechanism itself is activated at start level 20, so scripts cannot be executed earlier than this.

Note that prior to openHAB 3, script ordering was performed alphanumerically based on file path. This is no longer supported as of openHAB 3 and later versions.

# ScriptExtension Objects (all JSR223 languages)

To facilitate JSR223 scripting, several openHAB-related variables are automatically predefined within ScriptExtension presets. They can be loaded into the script context using scriptExtension.importPreset(String preset), e.g. scriptExtension.importPreset("RuleSimple"). The default preset is preloaded, so it does not require importing. With scriptExtension.get("automationManager") the automationManager can be made available without loading a preset.

• Overview
  • Example rules for a first impression
  • Script Locations
  • ScriptExtension Objects (all JSR223 languages)
    • Default Preset (importPreset not required)
      • events operations
    • RuleSimple Preset
    • RuleSupport Preset
    • RuleFactories Preset
    • ScriptAction Preset
    • cache Preset
  • TriggerType Objects (all JSR223 languages)

# Default Preset (importPreset not required)

# events operations

• events.postUpdate(String, String)
• events.postUpdate(Item, Number)
• events.postUpdate(Item, String)
• events.postUpdate(Item, State)
• events.sendCommand(String, String)
• events.sendCommand(Item, Number)
• events.sendCommand(Item, String)
• events.sendCommand(Item, Command)
• events.storeStates(Item...)
• events.restoreStates(Map<Item, State>)

# RuleSimple Preset

These variables and classes are loaded using:

scriptExtension.importPreset("RuleSimple")

The primary usage of this preset is for defining rule (SimpleRule) subclasses. See language-specific documentation for examples.

# RuleSupport Preset

These variables and classes are loaded using:

scriptExtension.importPreset("RuleSupport")

# RuleFactories Preset

Note: Advanced usage

scriptExtension.importPreset("RuleFactories")

# ScriptAction Preset

This preset can be useful for scheduling asynchronous code execution with org.openhab.core.automation.module.script.action.Timer.

scriptExtension.importPreset("ScriptAction")
scriptExtension.importPreset("RuleSupport")
scriptExtension.importPreset("RuleSimple")

scriptExecution.createTimer(ZonedDateTime.now(), {
  org.slf4j.LoggerFactory.getLogger('Test logger').warn('Timer ran')
})

actions.scriptExecution.createTimer(time.toZDT(1000), () => {
  console.info('Timer ran');
})

createTimer(now.plusSeconds(1), [ |
  logInfo('Test logger', 'Timer ran')
])

after(1.second) do
  logger.info("Timer ran")
end

# cache Preset

The cache preset does not provide a default import and needs to be imported explicitly.

scriptExtension.importPreset("cache")

sharedCache.put("x", "y")

scriptExtension.importPreset("cache")

var valueX = sharedCache.get("x")

var { sharedCache, privateCache } = require('@runtime/cache')

sharedCache.remove("x")

sharedCache.put('foo', 'bar')
sharedCache.get('foo') // returns null if doesn't exist
shareCache.put('foo', null) // deletes the entry

scriptExtension.importPreset("cache")

# the preset is imported automatically by the helper library.
value_x = shared_cache[:x]
shared_cache.delete(:x)
shared_cache[:x] = "y"

It provides two different caches:

• sharedCache: This cache is shared over all languages and all scripts (file-based and UI). Usage of entries is tracked and entries will be removed if the last script that ever accessed an entry is removed.
• privateCache: This cache is private to a script engine, usually that means it is private to a script or rule, depending on the implementation of the scripting language. It is cleared when the script engine is unloaded (i.e. usually when the script is unloaded).

In both cases values that are either a ScheduledFuture<?> or a Timer are cancelled by calling .cancel() on the object if the object is removed automatically.

Both caches implement the org.openhab.core.automation.module.script.rulesupport.shared.ValueCache interface and therefore can be accessed by

• Object put(String key, Object value): Put a key/value pair to the cache. Returns old value if already set, otherwise null.
• Object remove(String key): Remove the key/value pair from the cache. Returns old value if already set, otherwise null.
• Object get(String key): Get the value for the given key from the cache. Non-existent keys return null.
• Object get(String key, Supplier<Object> supplier: Get the value for the given key. If no value is present, add the value that is return from the supplier.

# TriggerType Objects (all JSR223 languages)

The following trigger types are defined by openHAB (custom triggers can also be defined) and take the specified configuration parameters. All parameters are Strings. Read the JSR223 language specific documentation for examples of using these TriggerType objects.