harcon-radiation

Harcon-Radiation - An extension to the harcon library to automatically expose selected entities through REST and/or Websocket.

!Note: Please be aware, that from version 1.3.0, harcon-radiation requires Node 4.0.0 or above...

================ harcon-radiation is a small, yet handy tool extending the harcon library to provide a REST-, and Websocket-based interface to it.

Every time you publish or revoke an object-based entity, the harcon-radiation reacts to the changes and maintain the interfaces transparently.

Installation

$ npm install harcon-radiation

Quick setup

var harcon = new Harcon( { ... } );
var radiation = new Radiation( harcon );
var rest = require('connect-rest');
var connect = require('connect');
...
var app = connect();
...
app.use( radiation.rester( rest, options ) ); // Activates the REST services
...
server = http.createServer(app);
io = radiation.io( io.listen( server ) ); // Activates the Websocket services
...
harcon.addicts( {
	name: 'julie',
	context: 'book',
	rest: true,
	websocket: true,
	log: function( data, callback ){
		callback( null, 'Done.' );
	}
} );

The example shows how you can attach the radiation to a connect/express instance and link to your harcon instance. You can activate the REST and Websocket interfaces only or both as you wish. Any object-based entities published to harcon possessing attributes 'rest' and 'websocket' will be exposed through those interfaces automatically.

Regulate publishing process

The default behavior is to publish all services. However, one can define rules to make exceptions. By setting the option hideInnerServices, harcon-radiation will hide inner services and won't publish them

var radiation = new Radiation( harcon, { hideInnerServices: true } );

harcon-radiation ignores a service in 2 cases:

• its name starts with a given prefix

	var radiation = new Radiation( harcon, { hideInnerServices: true, innerServicesPrefix: '_' } );

• its name matches to a given pattern

	var radiation = new Radiation( harcon, { hideInnerServices: true, innerServicesFn: function(name){
		return name.startsWith('inner') || name.startsWith('sys');
	} } );

Call in from remote

REST interface means a POST service using the same addressing logic as was implemented in harcon. An division-aware URI composed by name or context and a service function's name

post -> 'http://localhost:8080/Inflicter/book/log'

with body

{ params: [ 'Hello!'] }

will do perfectly.

Using Websockets is also straightforward:

var socket = ioclient( 'http://localhost:8080/Inflicter' );
socket.emit('ignite', { division: 'Inflicter', event: 'book.log', params: [ 'Helloka!' ] } );

The lib will open the namespace 'Inflicter' listening incoming packets. By sending an 'ignite' message passing the communication you want to deliver will do fine.

harcon-radiation supports JSON-RPC 2.0 if you create the instace as follows:

	var radiation = new Radiation( harcon, { jsonrpcPath: '/JSONRPC' } );

This will accept POST request on the given path in regard with the JSON-RPC 2.0 standard. Setting the 'jsonrpcPath' attribute will also open a Websocket namespace listening incoming JSON-RPC 2.0 packets.

Note: be aware the limitations of JSON-RPC. It does not support orchestration like divisions or contexts, therefore addressing should be limited to entityname.service.

Emit message to websocket listeners

You can send out / broadcast messages to connected listeners if your business entity calls the method 'shifted', which is a built-in service of harcon letting entities to inform the system about state changes. harcon-radiation uses this mechanism to send out those messages to the websocket listeners.

	this.shifted( { mood: 'happy' } );

That will send the message 'mood' to the connected clients with the data 'happy'. All properties of the object sent will be turned into separate messages to be broadcasted. And the payload of the messages will be set by the value of the given property.

Note: Considering the nature of the JSON-RPC 2.0, this level of service is available only for the 'normal' websockets clients.

Security

harcon-radiation is using connect-rest inside and allows you to use the security features of that REST lib. Your components might possess a protector function which should retrieve protector function used by the connect-rest when it is called. The service parameter can be used to differentiate the different security aspects your services cover.

harcon.addicts( {
	name: 'julie',
	rest: true,
	security: {
		protector: function(service){
			return function( req, res, pathname, path, callback ){
				callback();
			}
		}
	}
} );

About the protector functions, please find the description here.

License

(The MIT License)

Copyright (c) 2016 Imre Fazekas

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Bugs

See https://github.com/imrefazekas/harcon-radiation/issues.

Changelog

• 1.6: JSON-RPC support added
• 1.1-1.4: refactoring
• 1.0.0 : moving to harcon v2
• 0.8.0 : addressing via names added
• 0.5.0 : refactoring and moving to harcon v1
• 0.1.0 : initial release