Collaborative.ws

Collaborative Point of View
Document Centric SOA
Jeremy Deane, Technical Architect, [email protected], October 2007 TABLE OF CONTENTS
LIST OF FIGURES
Remote Procedure Call vs. Document-Literal Collaborative Point of View
1. Document Centric SOA
Figure 1 Remote Procedure Call vs. Document-Literal
1.1 Background
HTTP Request or Response
HTTP Request or Response
HTTP HEADERS
HTTP HEADERS
an approach for building softwareservices, regardless of location orownership, that map directly to HTTP Body
HTTP Body
SOAP Envelope
SOAP Envelope
SOAP HEADERS
SOAP HEADERS
SOAP Body
SOAP Body
ever-changing business requirements.
RPC Parameters
XML Document
For instance, a new service can becomposed of existing services,creating a new business process, orcan simply delegate to anotherservice, extending a business process.
SOAP- RPC
SOAP- XML
implemented services based onSimple Object Access Protocol(SOAP) and remote procedure calls 1.2 Exchanging Business
Documents
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Figure 2 Document Centric Services
<<artifact>>
<<artifact>>
Linux Server
<<document>>
<<execution environment>>
Municipal Web Application
Client Laptop
Linux Server
Registration
Recycling Bill
<<execution environment>>
<<execution environment>>
Municipal Web Application
Registration
Web Service
XML Web Service
From Data
Registration
Registration
Recycling
Registration
Registration
Unix Server
Recycling
<<execution environment>>
Waste Mgmt. Application
<<document>>
Management
<<artifact>>
<<artifact>>
<<artifact>>
Web Service
1.3 Service Implementation Options
resource, identified by a unique ID.
registering to vote is an activity whilesubmitting a voter registrationdocument is updating a resource.
2Representational State Transfer (REST) originated from Roy Thomas Fielding's PhD Dissertation Collaborative Point of View
Figure 3 SOAP vs. REST
The most common resourcerepresentation format is an XML HTTP Request or Response
HTTP Request or Response
document, optionally defined by anXSD. A resource representation often HTTP HEADERS
HTTP HEADERS
contains not just data but links toother resources as well. The resource HTTP Body
HTTP Body
SOAP Envelope
SOAP HEADERS
XML Document
SOAP Body
XML Document
each service request results in anupdated application state, a specificresource’s state only changes in thecase of a PUT, POST or DELETE.
The Request and Response messagesimplement a standard format that SOAP- XML
REST - XML
includes a header and a body. Sincethe RESTful services are stateless, thesecurity information must be passedin each request. To secure a request, services is to use a RESTful approach.
1.4 RESTful Document Centric
Services
Resource Indicator (URI), over HTTP3.
steps, toolkits and execution engines.
3A RESTful service can also be invoked asynchronously using the Request-Reply Integration Pattern Collaborative Point of View
Figure 4 RESTFul Document Centric Service
<<document>>
Linux Server
<<execution environment>>
<<execution environment>>
Web Server
HTTP GET Request
HTTP Response: 200 (OK)
<<document>>
1.5 Service Provisioning
regardless of transport is addressing.
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Figure 5 NetKernel Enterprise Service Bus
Unix Server
<<document>>
<<execution environment>>
Linux Server
Demilitarized
Application Server
HTTP GET Request
<<execution environment>>
Apache Web Server
Application
HTTP Response: 200 (OK)
Security Filtering
<<document>>
Route and Transform Document
Linux Server
<<execution environment>>
NetKernel
<<document>>
<<document>>
sends the file onto the Oracledatabase using FTP. Linux Server
Linux Server
1.6 Service Governance
<<execution environment>>
<<execution environment>>
Oracle Database
PeopleSoft
Benefits
provides an accountability framework.
Warehouse
Application
Service accountability is requiredsince a service may span lines ofbusiness or several organizations.
Governance ensures that services arenot overused, or worse misused, byenforcing policies and maintaining 4Actional SOA Management Product Suite Collaborative Point of View
Figure 6 Actional Business Process Visibility
1.7 Summary
A Document Centric SOA consists ofreusable services exchanging businessdocuments. Using schemas to definethe contents of the documentscreates an enterprise domain modelindependent of a platform orapplication. An enterprise domainmodel provides an organization witharchitectural agility since integratedsystems do not rely on each other’smessage structure or data types. Thusthe replacement of a system ofrecord, such as legacy application,may require an update to the ESB butwill have little or no impact on theconsuming applications.
Using a RESTful approach toimplement document-centric serviceslowers the initial cost of entry andincreases the time to market. REST ispreferred over SOAP because REST isbased on the stable principles of theweb rather than a set of everchanging vendor-driven specifications.
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2. References
Service Oriented Architecture
• OASIS SOA Reference Architecture
http://www.oasisopen.org/committees/download.php/19679/soa-rm-cs.pdf • Service-Oriented Architecture: Concepts, Technology, and Design by Thomas Erl http://www.soabooks.com/chapters2.asp http://1060.org/upload/IntroductionToResourceOrientedComputing-1.pdf • Understanding Enterprise Service Bus Part I-III by Rick Robinson http://www-128.ibm.com/developerworks/webservices/library/ws-esbscen/ • Understanding SOA Governance by Lori MacVittie http://www.networkcomputing.com/showArticle.jhtml?articleID=191203018&queryText=centrasite Web Services
• W3C Web Services Architecture
• Web Services: Concepts, Architectures and Applications by Alonso, Casati, Kuno & Machiraju http://www.inf.ethz.ch/personal/alonso/WebServicesBook • Web Services Interoperability Organization • Resource-oriented vs. activity-oriented Web services by James Snell http://www-128.ibm.com/developerworks/xml/library/ws-restvsoap/ • RESTful Web Services by Leonard Richardson, Sam Ruby http://www.oreilly.com/catalog/9780596529260/ Extensible Markup Language (XML)
• Extensible Markup Language (XML)

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