- Resource Oriented Architecture (ROA) is a concept where every interactable item in an enterprise is represented as a resource that can be accessed using uniform interfaces like HTTP methods. This allows an enterprise to be distributed, ubiquitous, and agile. - WSO2 middleware can help build a ROA by exposing systems and data as resources, integrating systems, and providing tools to manage resources and APIs in a loosely coupled, secure manner. This moulds an enterprise according to the needs of a connected enterprise.

1. Moulding your Enterprise with
Resource Oriented Architecture
Shiroshica Kulatilake
Solutions Architect
WSO2

2. Agenda
• Needs of a Connected Enterprise
• Resource Oriented Architecture - Concepts
• How Resource Oriented Architecture complements
a Connected Enterprise
• Building a Resource Oriented Enterprise
Architecture with WSO2

3. Fulfilling the Needs of a Connected Enterprise

4. Needs of a Connected Enterprise
• Distributed
– Built on many interactions utilizing strengths of the
connected network
– Connects across several boundaries
• Ubiquitous
– Accessible via many end devices
– Accessible from any location
– Use of public modes for access e.g. Web
• Agile
– Flexible interacting with multiple partners
– Flexible in adapting to changing requirements
– Time to market is very low

5. How would an Enterprise Achieve these Needs

6. By creating an Enterprise Architecture Vision

7. Defining Enterprise Architecture
An enterprise architecture (EA) is a conceptual
blueprint that defines the structure and operation of
an organization.
The intent of an enterprise architecture is to determine
how an organization can most effectively achieve its
current and future objectives.

8. From an Enterprise Architect’s POV
• Distributed
– Integrate seamlessly with existing and new systems
– Ease of creating new services and composites
– Ease of exposing created services in a secure manner
• Ubiquitous
– Ease of accessing exposed services in a secure manner
– Create applications/mashups which are lightweight
– Make use of common Web Technology
• Agile
– Easy to learn and use technology
– Able to design and build in a short time period

9. Defining an Enterprise Architecture

10. Resource Oriented Architecture
- The Concepts

11. Resource Oriented Architecture
• Each and every interactable item in an enterprise is
represented as a Resource
• Representational State Transfer (REST) is the pattern
which is used to achieve this
• The complete system is modeled in a logical manner
• Loose Coupling is advocated
• State is determined based on the actions performed
on the resources and the representations

12. ROA : Unique Naming
• Resource names are unique in a global context
• URL is the unique identifier in ROA
• URL = URN + Context information
– http://wso2.com/customers/apac/1123
• It will have the context (where) plus the unique key

13. ROA : Logical Representation
• The URL will be an indefinite constant since clients
depend on this
• It should not include
– Implementational details
• http://wso2.com/customer.jsp?id=1123
– Contractual information
• http://wso2.com/customers/apac/v1/1123
• Meta information can be added as parameters to
the URL which would add more context and
flexibility
– http://wso2.com/customers/apac/1123?version:v1
• Self explanatory

14. ROA : Uniform Interfaces
• Accessing the resources should follow the same
pattern
– Action : Uniform Identifier
• ROA is based on REST which is powered by HTTP
• For all resources the interface methods used are the
same
– GET (Query), POST (Create), PUT (Update), DELETE (Remove)
– curl GET http://wso2.com/customers/apac/1123
• Uniform interfaces makes dealing with these
resources much simpler for clients

15. ROA : Freedom of Form
• A resource can have many representations
• Representation is independent of the name
• The form should be defined in the HTTP request
header
– curl -H “Accept: application/json” -O http://wso2.com/customers/apac/1123
• The Client has total control
• The server simply responds with the information in
the required representation

16. ROA : Loose Coupling
• The client is only bound to the URL and Resource
details that it received and not to the server
• Server implementation is independent and thus can
be refactored when needed provided it sends out
the same resource details
• Resource does not have any implementation
specifics

17. ROA : Late Binding
• The first call may not provide the actual resource -
but simply a collection with metadata
– curl -H “Accept: application/json” -O http://wso2.com/customers/apac/
– [“http://wso2.com/customers/apac/1123” , “http://wso2.
com/customers/apac/1126”]
• It would be subsequently that the actual resource is
requested
• This enables the ability to do fine grained access
control

18. ROA : HATEOAS
• Hypermedia As The Engine of Application State
• Application state is transferred with the responses
• Application state is transferred via links
• The Client needs to
– interact with the server only via hypermedia
– figure out possible actions through the resource
representation sent
GET http://wso2.com/customers/apac/1123
{
“name” : “Alice Grey”,
“ID” : 1123,
“promote”: “http://wso2.com/customers/apac/1123/promote”
}

19. When to use Resource Oriented Architecture
• Systems which have clearly defined entities, which
have clear associations and can be logically modeled
• Systems which will evolve rapidly
– Growth in entities
– Change in server implementation
• Systems where the client needs to use lightweight
web technologies
• Systems which can be developed quickly

20. ROA in a Connected Enterprise
• Distributed
– Multiple entities(Systems and Things) with context and
association
– Loosely coupled
– Not bound to contracts / services
– Can evolve easily into a large ecosystem
• Ubiquitous
– Works on technology that supports ubiquity
– Secure - OAuth, OpenID Connect
– Lightweight with low overhead
• Agile
– Easy to design
– Simple yet powerful technology

21. Building a Resource Oriented Architecture with
WSO2 Products

22. Steps to Build a Resource Oriented
Enterprise Architecture
• Identify the entities (nouns) in the system and their
relationships
– Design the resources
– Design the access methods (which verb action)
– Determine security
• Identify how state can be represented via responses
– Define additional resources plus links for state
• Design granularity
– Determine metadata for resources
– Identify security at each level of granularity
• Implement with REST

23. What does WSO2 offer ?

24. Platform of Platforms

25. Platforms which are well Integrated

26. Expose Base Services
- SOAP services
- REST services
- REST services - SOAP services
- REST services
- OData services

27. Integrate Systems and Data

28. Expose Managed APIs

29. Provide Tools to Manage

30. Summary
• ROA in essence would be considering all entities as
resources which are connected in a logical manner
• With ROA an enterprise can aim to be distributed,
ubiquitous and agile
• Fits in well with the needs of a Connected
Enterprise
• WSO2 middleware is capable of moulding your

31. References
1. http://searchcio.techtarget.com/definition/enterprise-architecture
2. http://inspire.ec.europa.
eu/reports/ImplementingRules/network/Resource_orientated_archit
ecture_and_REST.pdf
3. http://www.infoq.com/articles/roa-rest-of-rest
4. http://wso2.com/library/webinars/2015/09/resource-oriented-
architecture/
5. https://www.ics.uci.edu/~fielding/pubs/dissertation/rest_arch_style.
htm
6. http://wso2.com/library/webinars/2015/12/wso2-year-end-technical-
update-webinar/

32. Thank You