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Actinium (Ac) App-server 2.0 for Californium

Version 2.0 is now based on Nashorn and provides module loading mechanism

Our novel runtime container Actinium (Ac) exposes scripts, their configuration, and their lifecycle management through a RESTful programming interface using the Constrained Application Protocol (CoAP). We endow the JavaScript language with an API for direct interaction with mote-class IoT devices, the CoapRequest object, and means to export script data as Web resources. With Actinium, applications can be created by simply mashing up resources provided by CoAP servers on devices, other scripts, and classic Web services.

Maven

Actinium can only be built using JDK 1.8 because of its dependencies to some JDK internal classes (you are more than welcome to help us getting rid of them). Use mvn clean install in the root directory to build the Actinium (Ac) server. A standalone JAR will be created in the ./run/ directory.

The dependencies are available from the default Maven repositories.

Run with java -jar actinium-*.jar.

If newer JDKs are used to run maven, -DuseToolchain can be used to switch back to the required JDK 1.8

mvn clean install -DuseToolchain

Eclipse

The project also includes the project files for Eclipse. Make sure to have the following before importing the Californium (Cf) projects:

Then choose [Import... » Git » Projects from Git » Local] to import californium.actinium into Eclipse.

Run org.eclipse.californium.actinium.AcServer as Java application.

Usage

Prerequisites

Make sure the ./appserver/ directory with config.cfg exists when you run Actinium (Ac), which can be found in the ./run/ directory (must be copied when running from Eclipse). ./appserver/installed/ contains several example scripts. ./appserver/apps/ contains the configurations of app instances. Some of the start automatically depending on the start_on_startup flag.

Installing a New App

Send a POST with JavaScript code to install?[appname] where [appname] is used as (file)name for the app code.

Example:

	Request:  POST coap://localhost:5683/install?helloWorld
	Payload:  app.root.onget = function(request) {
                  request.respond(2.05, "Hello World");
	          }
	Response: Application appname successfully installed to /install/helloWorld

The example app ist stored in ./appserver/installed/ as helloWorld.js. The server now has a new resource /install/helloWorld.

Starting a New App Instance

Send a POST with "name=[instance name]" to /install/helloWorld where [instance name] is used as name of the instance as well as filename for the configuration. You can instantiate an installed app several times by choosing different instance names.

Example:

	Request:  POST coap://localhost:5683/install/helloWorld
	Payload:  name=hello-1
	Response: Application hello-1 successfully installed to /apps/running/hello-1

The example instance is stored in ./appserver/apps/ as config_hello-1.cfg. The server now has two new resources, /apps/appconfigs/hello-1 to change the configuration of the instance and /apps/running/hello-1 to interact with the running app.

Communicating With a Running App

Send GET, POST, PUT, or DELETE to a resource under /apps/running/ depending on what functionality was implemented in the JavaScript code.

Configuring an App Instance

Some of the instance properties can be changed during runtime, some are fixed (e.g., the name). The changes are committed to the config resource of the app under /apps/appconfigs/. For this, use a POST with key = value pairs as payload to update existing keys. Use PUT to clear all existing keys and start fresh with the keys in the PUT payload.

There are also three special commands to control the running instance via POST: start, restart, and stop.

Example:

	a) Request:  GET coap://localhost:5683/apps/appconfigs/hello-1
	   Response: All app properties
	   
	b) Request:  POST coap://localhost:5683/apps/appconfigs/hello-1
	   Payload:  enable_request_delivery = false
	   Response: successfully changed keys: [enable_request_delivery]
	   [App hello-1 cannot receive any more request]
	   
	c) Request:  POST coap://localhost:5683/apps/appconfigs/hello-1
	   Payload:  restart
	   Response: put running = restart
	   [App hello-1 is restarting]

Programming Your Own Apps

To respond to CoAP requests, simply set the following onX functions on a JavaScriptResource. They have the request as argument, which can be responded through its respond(code, payload) method. app.root is the root resource of your app under /apps/running/.

Example:

	app.root.onget = fnc;
	app.root.onpost = fnc;
	app.root.onput = fnc;
	app.root.ondelete = fnc;
	
	fnc = function(request) { 
		request.respond(2.05, "Hello World"); 
	}

Sub-resources can be added to the root resource as shown below:

	res = new JavaScriptResource('mySubResource');
	app.root.add(res);

You can dump information to the console through the app object:

	app.dump("Hello World");
	app.error("Houston, we have a problem");

AcShell

The AcShell can be used to run a single app from the command line. Start with:

Windows:
	java -cp target/actinium-*.jar org.eclipse.californium.actinium.AcShell file.js

Linux:
	java -cp target/actinium-*.jar org.eclipse.californium.actinium.AcShell file.js