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Web Oriented Architecture (reloaded)

Emiliano PecisTechnology Business Unit

Wake Up, Neo. SOA has you…

Red or Blue pill?

WOA SOA

Agenda

WOA & SOA

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“In other words, the Web model provides a single, open, and unified

information architecture that is consistent, easily consumed,

extremely scalable, securable, very reusable, resilient, and highly

federated.”

Dion Hinchcliffe Founder, Hinchcliffe & Co.

Dion Hinchcliffe’s Blog

WOA – Web Oriented Architecture

WOA & SOA

WOA versus SOA: not a competition

The elements of WOA

Make it simple with mashups

WOA – All About Resources

WOA and low case semantic web

ReST vs SOAP

Introducing REST

• Nouns: All resources, or nouns, are network-addressable with a global URL. Resources have “href” references to other related resources. The only way to address a resource is with a URL.

• Verbs: A common set of verbs are used to access all resources. The HTTP methods GET, PUT, POST, and DELETE map to retrieve, update, create, and delete (CRUD) functions.

• Representations: A resource might be represented as XML, JSON, HTML, text, image, and so on. Instantiating representation from or to the resource is handled on the server. A client can pick its preferred representation via a URI parameter or the “Accept:” header.

REST Patterns 1/2

• Give every “thing” an ID (URI):• http://example.com/orders/2007/11

• Link things together (Hypermedia links):• <order self='http://example.com/customers/1234' >

<amount>23</amount> <product ref='http://example.com/products/4554' /> <customer ref='http://example.com/customers/1234' /> </order>

• Use standard methods (HTTP verbs) • GET is safe and idempotent• PUT and DELETE are not safe but are idempotent• POST is neither safe nor idempotent

REST Patterns 2/2

• Resources with multiple representations• GET /customers/1234 HTTP/1.1

Host: example.com Accept: application/vnd.mycompany.customer+xml

• GET /customers/1234 HTTP/1.1Host: example.com Accept: text/x-vcard

• Communicate statelessly • Cookies shouldn’t be used to encode information that can be

transferred by other, more standardized means

REST Anti Patterns

• Tunneling everything through GET or POST• http://example.com/some-api?method=deleteCustomer&id=1234• Resources are not identified by URIs; rather, URIs are used to encode

operations and their parameters• The HTTP method does not necessarily match the semantics• Such links are usually not intended to be bookmarked• There is a risk that “crawlers” (e.g. from search engines such as Google)

cause unintended side effects

• Ignoring caching • Cache-control: no-cache (always)

• Ignoring status code• Misusing of 200 or 500 status code

Processes and Resources

REST API

Sponsored Slide: WLP is REST enabled

Developing a scalable WOA

WOA and (server side) scalability

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Application Servers

Web Servers

Ever Expanding Universe of Users

The need of a Datagrid

• Data grid brokers Data Supply with Data Demand

• Scale out Data Grid in middle tier using commodity hardware

Data Sources

Data Demand

Java Objects

What is a datagrid?

Caching

Applications request data from the Data Grid rather than backend data sources

Analytics

Applications ask the Data Grid questions from simple queries to advanced scenario modeling

Transactions

Data Grid acts as a transactional System of Record, hosting data and business logic

Events

Automated processing based on event

How does it work?

• Data spread and backed up across Members

• Transparent to developer

• Members have access to all Data

• All Data locations are known – no lookup & no registry!

• Synchronous Update

• Avoids potential Data Loss & Corruption

• Predictable Performance

• Backup Partitions are partitioned away from Primaries for resilience

• No engineering requirement to setup Primaries or Backups

• Automatically and Dynamically Managed

• Write-behind

How does it work?

• Membership changes (new members added or members leaving)

• Other members, using consensus, recover and repartition automatically

• No in-flight operations lost, no availability gap!

• Some latencies (due to higher priority of asynchronous recovery)

• Information Reliability & Continuous Availability are the priorities

How does it work?

Sponsored Slide: Oracle Coherence

• Implements Map interface• Implements JCache interface• Real-time filterable (bean) events • Filters completely extensible• Processors applied in parallel (grid)• A large range of filters out-of-the-box• Implements listeners

WOA actors

Client sideClient side Server sideServer side

WOA actors #1: AJAX

• Asynchronous JavaScript and XML• Combination: XMLHttpRequest, xml,

dom, html, json• Enables the partial page refresh

feature

WOA actors #2: JS frameworks

• More high level than pure javascript

• Examples: dojo, scriptaculous, prototype, jquery, mooTools, yui

• A lot of stuff done, just invoke it!• Ready for ajax and json

WOA actors #3: Json

• JavaScript Object Notation• More light than XML (data with

less structures)• Directly interpretrated by javascript• No effort for creating / (de)

serializing a tree dom• Tens folders more fast• More simple to traverse and get

attributes

WOA developers love…

• Agile MVC framework like Grails• Complete lightweight container

like Spring• Lightweight application server• ORM like Toplink or Hibernate• Data cache layer like Coherence

or ehcache

Sponsored Slide: Weblogic Suite

• Startup the container with just a web profile (no ejb, no rmi, no jca, no jms)

• Weblogic Server supports Spring with a dedicated console

• Weblogic Server uses Toplink as ORM

• Weblogic Suite includes Oracle Coherence for the datagrid

• Coherence*Web is used to manage sessions in a datagrid fashion and to cache WLP objects

Scaling a SOA with the Datagrid

What does the scalable architecture need to ensure

• Avoid processing where possible • Avoid I/O where possible• Avoid serialization and de-serialization• Avoid sending large documents over network• Avoid distributed file schemes as your app scales up• Avoid driving increasing traffic to backend systems • Architect for performance from the beginning aka not

throwing hardware at the problem!

Data Grid for SOA Services

Benefits

• Up to10 fold reduction in latency times used Cached data

• Cache available to other nodes in the cluster.

• Data grid provides backup of cache to peer nodes

• Cache can be persisted to the database using a number of mechanisms.

Service Bus

Portal

Orchestration Engine

ServiceProvider

[data item]

[data item]

Service

MySelfServPortal

CoherenceGrid

NearCache

CacheThis is a very large piece of customer data that has to be obtained in one go from the system.

Restifying and caching a SOA

• Problem• Siebel CRM works properly, but doesn’t scale as expected

• Challenges• Customer requires rapid access to accurate information• All data must be available for a Social CRM Mashup• Customer wants to cache better the most frequently invoked services

• Solution (*)• Implement a solution that is able to restify and cache all needed WS-SOAP

exposed by Siebel

(*) Custom solution, it’s not a product: just for demo purpose

Restifying and caching a SOA

RSD: parse the URL

http://siebel.com/rsd/catalog/product/id/5461

?n1=v1&n2=v2…

get / put / post / delete

RSD: check if cachedCheck the cache only

if GET method has been used Assign a XML payload

to a variable

Send the payload to Coherence through the OSB Transport

if Coherence is not UP a WS call will be done

If the item is not in the cache a WS call will be

done)

Skipcache variable will be tested to decide if it is the case to return the cached value or

invoke the WS

RSD: check if cachedCheck the cache only

if GET method has been used Assign a XML payload

to a variable

Send the payload to Coherence through the OSB Transport

if Coherence is not UP a WS call will be done

If the item is not in the cache a WS call will be

done)

Skipcache variable will be tested to decide if it is the case to return the cached value or

invoke the WS

RSD: check if cachedCheck the cache only

if GET method has been used Assign a XML payload

to a variable

Send the payload to Coherence through the OSB Transport

if Coherence is not UP a WS call will be done

If the item is not in the cache a WS call will be

done)

Skipcache variable will be tested to decide if it is the case to return the cached value or

invoke the WS

RSD: the configuration file

GET /rsd/catalog/categories/id/3473

The following URI parts select the needed WS parts:

This is the SOAP

operation to invoke

This is the SOAP

payload to load

This is the SOAP

response to return

But, what about the

URL parameters

?

RSD: the configuration file

GET /rsd/catalog/categories/id/3473

RSD: check if cachedCheck the cache only

if GET method has been used Assign a XML payload

to a variable

Send the payload to Coherence through the OSB Transport

if Coherence is not UP a WS call will be done

If the item is not in the cache a WS call will be

done)

Skipcache variable will be tested to decide if it is the case to return the cached value or

invoke the WS

RSD: check if cachedCheck the cache only

if GET method has been used Assign a XML payload

to a variable

Send the payload to Coherence through the OSB Transport

if Coherence is not UP a WS call will be done

If the item is not in the cache a WS call will be

done)

Skipcache variable will be tested to decide if it is the case to return the cached value or

invoke the WS

P

BBackup

Node

PrimaryNodeGet / Put (Cachekey)

Service Data

Coherence Data Grid

OSB ResultCache

Ora

cle

Serv

ice B

us

1. check cache

2. if results not in cache, invoke service & cache results

Resource

SOAP/XML

REST/JSON

Ora

cle

Web

log

ic

Porta

l O

ther

Porta

ls

•Siebel•WCM•Wiki•Blog•Forum•…

Any Web Services

Clie

nt /b

row

ser

Restful Datagrid Reasonings

• In REST each resource has a unique URL• This URL is the primary key for the Datagrid (Coherence)• The cached value is stored in JSON format to be as

“client ready” as possible• REST and JSON give developers more flexibility,

ensuring a strong light-matter coupling between content and its rapresentation

• Javascript frameworks, like Jquery, allows developers to get JSON data from the datagrid and manipulate them as they prefer

Q&A