REST is a style of software architecture for distributed hypermedia systems such as the World Wide Web. It uses a stateless, client-server, cacheable communications protocol and standard interface to access and manipulate representations of web resources. The key aspects of REST include using a uniform interface, separating concerns through resources and representations, and hypermedia as the engine of application state. REST contrasts with SOAP which is message-oriented and focuses on integrated applications rather than interacting with resources. While REST and SOA share some principles like loose coupling and statelessness, REST emphasizes resources and representations over messages and operations.

1. REST Introduction

2. Agenda
• REST Concept
• REST Constrains
• REST Data Elements
• REST V.S. SOAP
• REST V.S. SOA
• How to be RESTful
• Q&A

3. REST Concept
REST is
• Representational State Transfer between Resourcebetween Resource
• A style of software architecture
• A Virtual state-machine
A network of web pages (a virtual state-machine),
where the user progresses through an application by selecting links (state
transitions), resulting in the next page (representing the next state of the
application) being transferred to the user and rendered for their use.

4. • Client-Server
• Separation principle
• Components Independent
• Stateless
• Session state on the client
• Visibility, reliability and scalability
• Trade off (network performance, etc.)
• Cacheable
• A response can be cacheable
• Efficiency but reduce reliability
• Layered system
• System scalability
• Code on demand (optional)
• Extension after deployment
• Uniform Interface
• Simple
REST Constraints

5. • Resources and Resource Identifiers
• Uniform Interface (GET, PUT, POST, DELETE)
• Resource Oriented
• Simple and simple is beautiful
REST Data Elements
HTTP Method CRUD Desc.
POST CREATE Create -
GET RETRIEVE Retrieve Safe,Idempotent,Cacheable
PUT UPDATE Update Idempotent
DELETE DELETE Delete Idempotent

6. Representations
• HTML / XML / images / sounds / …
REST Data Elements

7. SOAP
• Simple Object Access Protocol
• RPC protocol that go through firewalls
• Communication protocol between applications
• A format for sending messages
REST V.S. SOAP

8. REST
•“The Web is the universe of globally accessible information”
• Resource oriented
• User-driven interactions via forms
• Few operations (generic interface) on many resources
• URI: Consistent naming mechanism for resources
• Focus on scalability and performance of large scale distributed
hypermedia systems
SOAP
•“The Web is the universal transport for messages”
• Activity/Service oriented
• Orchestrated reliable event flows
• Many operations (service interface) on few resources
• Lack of standard naming mechanism
• Focus on design of integrated (distributed) applications
REST V.S. SOAP

9. Two of most common styles of use of Web Services
•Service-oriented architecture
• “Message oriented” (SOAP)
• Contract provided by WSDL
•REST
• Focus on interacting with stateful resources, rather than
messages or operations.
REST V.S. SOA

10. REST V.S. SOA
Correlation
• REST is an architectural style that inherently helps to attain some
of the basic SOA principles.
SOA principles
•Standardized Service Contracts
•Service Loose Coupling
•Service Abstraction
•Service Reusability
•Service Autonomy
•Service Statelessness
•Service Discoverability
•Service Composability
REST principles
•Unique identifiability of the
resources through URIs
•Uniform interface to access the
resources
•Navigability of the resource
representations through
hypermedia
•Statelessness

11. Q&A
REST Introduction

12. Thank you!
REST Introduction