Json-based Service Oriented Architecture for the web

JSON SOA-based Client/Server Application

Development

Kris Zyp

© SitePen, Inc. 2008. All Rights Reserved


Overview

SOA on the webService Method Description for defining servicesDojo based approach to SOA


SOA-Based Client/Server Model

Distribution of ProcessingUser response latencyProgramming modelVector of attackState management on server vs clientOffline capabilitiesInteroperability


Service Oriented Architecture on the Web

Web Service ProviderWeb Service Provider

CS Web CS Web ClientClient

Methods

Web Web ClientClient

Methods

Desktop Desktop ClientClient

Methods


Service Mapping Description

JSON-based service definition structureDefines

TransportParametersExpected ResponseDescription

Clients can use an SMD to build methods to auto-connect to endpoints


Service Types

RESTJSONPPlain GETFull read/write (PUT, POST, DELETE)

RPCJSON-RPC

Different URL forms/path/id?name=value


Dojo Includes SMDs for major web servicesSMDs for third party services

WikipediaYahooWikipedia

Web services can advertise their services


Dojo Support for SOA


Services


var services = new dojox.rpc.Service("/mySMD");

or

var services = new dojox.rpc.Service({

transport:”REST”,

services:{

newsService:{...}

}

});

services.newsService({query:"dojo"}.

addCallback(function(returnValue) {

alert("A news item: " + returnValue[0]);

});

var services = new dojox.rpc.Service("/mySMD");

or

var services = new dojox.rpc.Service({

transport:”REST”,

services:{

newsService:{...}

}

});

services.newsService({query:"dojo"}.

addCallback(function(returnValue) {

alert("A news item: " + returnValue[0]);

});

Example of Service Auto-Generation


Dojo Data


http://archive.dojotoolkit.org/nightly/dojotoolkit/dojox/grid/tests/test_yahoo_search.htmlhttp://www.sitepen.com/blog/2008/06/25/web-service-data-store/

ServiceStore

Adapts web services to dojo.data APIPlug services directly into widgetsSupports lazy loading


Read/Write (Real) REST Services

Full REST Services can plugin for full read/write ORM-style functionality:

GET - query and get by idPUT - update an objectPOST - create an objectDELETE - delete an object


schema:

{"description":"A person",

"type":"object",

"properties":

{"name": {"type":"string"},

"age" : {"type":"integer",

"maximum":125}}

}

instance:

{“name”:”Kris”,

"age":31}

schema:

{"description":"A person",

"type":"object",

"properties":

{"name": {"type":"string"},

"age" : {"type":"integer",

"maximum":125}}

}

instance:

{“name”:”Kris”,

"age":31}

JSON Schema


JSON Referencing

• Hyperlinking appplied to JSON

• Cyclic

• Multiple references

• Cross-message references

• Cross-site references


JsonRestStore

Full Read/Write APICreate, Read/Query, UpdateDelete

Standards Based (HTTP compliant)


Accompanied by Demo

JsonRestStore

Lazy loadingJSON ReferencingJSON SchemaTransactionalOffline Support


Push/Comet

Open Protocols for CometBayeuxXMPPREST Channels


Bayeux

• Service Negotiation

• Publish/Subscribe Protocol


REST Channels

• REST Based Push Protocol

• Based on HTTP standard semantics


HTTP/1.1 200 OK

X-Event: PUT

Content-Location: /foo/bar

New content of /foo/bar

HTTP/1.1 200 OK

X-Event: PUT

Content-Location: /foo/bar

New content of /foo/bar

HTTP Channels (REST Channels over HTTP)


Accompanied by Demo

{

“event”: “put”

“source”: “/foo/bar”

“content”: “New content of /foo/bar”

}

{

“event”: “put”

“source”: “/foo/bar”

“content”: “New content of /foo/bar”

}

REST Channels in JSON


Offline + REST

• REST + Thin Server = Easy Offline

• Dojo’s support for Offline SOA Applications


Security in SOA

• Security clearly distinct from UI code

• Assume users are directly accessing services

• Improved isolation of security


The browser is the platform of mashups

• Neutral ground, browser acts as a deputy/mediator

• JSON is the foundation for more complex data/code integration

• Cross-site mashup techniques emerging

http://www.sitepen.com/blog/2008/09/25/security-in-ajax/


Dojo Secure

Full framework for secure mashups Secure cross-site loading registry Adsafe style code validation Safe set of library functions Safe access to the DOM

http://www.sitepen.com/blog/2008/08/01/secure-mashups-with-dojoxsecure/


http://www.sitepen.com/blog/2008/07/18/clientserver-model-on-the-web/

Characteristics of good client/server application

• Clean Web API

• Interchangeability

• Presentation on the client

• Business logic on the server


Dojo’s SOA

• Service auto configuration

• Integration into Dojo Data model

• Full REST interaction support

• Comet and Offline capabilities

• All based on standards or emerging conventions, easy to switch to something else


The Open Web is more than just licensing


My other presentation

Applied JSON: REST, Ajax Databases


Technology

Json-based Service Oriented Architecture for the web