Openhab Javascript Library

This library aims to be a fairly high-level ES6 library to support automation in Openhab.

API Documentation

Requirements

• ES6 (e.g. GraalJS)
• CommonJS support

Installation

• Install the Openhab 'Experimental Rule Engine' in Paper UI
• Install the GraalJS bundle to upgrade JS runtime to ES6
• Ensure that you have created the automation scripting directories
• Go to the javascript community lib directory: cd $OPENHAB_CONF/automation/lib/javascript/community
• npm i ohj (you may need to install npm)

Usage

You should create scripts in $OPENHAB_CONF/automation/jsr223/javascript/personal.

The API can be imported as a standard CommonJS module: require('ohj'). The ohj module itself has various sections that can be imported as properties of the primary import, e.g.

//use destructing
const { rules, triggers } = require('ohj');
//or simply
const rules = require('ohj').rules;

Fluent API

The fluent section of the API can be used to write rules in a high-level, readable style.

The cleanest way to use the API is with a with statement. This is so that it's possible to use the exported functions without a prefix. An alternative approach (to allow 'use strict') would be to explicitly import the functions that you use, such as const {when, then} = require('ohj').fluent. The following examples will use the with style of importing.

Note that for the timeOfDay API, you must create a vTimeOfDay String item, which is updated like in the Openhab pattern. A future release will check this.

Fluent Examples

with(require('ohj').fluent){

    //turn on the kitchen light at SUNSET
    when(timeOfDay("SUNSET")).then(sendOn().toItem("KitchenLight"));

    //turn off the kitchen light at 9PM
    when(cron("0 0 21 * * ?")).then(sendOff().toItem("KitchenLight"));

    //set the colour of the hall light to pink at 9PM
    when(cron("0 0 21 * * ?")).then(send("300,100,100").toItem("HallLight")

    //when the switch S1 status changes to ON, then turn on the HallLight
    when(item('S1').changed().toOn()).then(sendOn().toItem('HallLight'));

    //when the HallLight colour changes pink, if the function fn returns true, then toggle the state of the OutsideLight
    when(item('HallLight').changed().to("300,100,100")).if(fn).then(sendToggle().toItem('OutsideLight'));
}

//and some rules which can be toggled by the items created in the 'gRules' Group:

with(require('ohj').fluent.withToggle) {

    //when the HallLight receives a command, send the same command to the KitchenLight
    when(item('HallLight').receivedCommand()).then(sendIt().toItem('KitchenLight'));
 
    //when the HallLight is updated to ON, make sure that BedroomLight1 is set to the same state as the BedroomLight2
    when(item('HallLight').receivedUpdate()).then(copyState().fromItem('BedroomLight1').toItem('BedroomLight2'));

    //when the BedroomLight1 is changed, run a custom function
    when(item('BedroomLight1').changed()).then(() => {
        // do stuff
    });
}