The document discusses RESTful web services and compares them to other types of web services. RESTful services use HTTP and embrace principles like making everything a resource, using clean and descriptive URIs, and representing state through representations. They avoid bandwidth overhead and leverage existing web protocols and infrastructure. Other types of web services, like WS-*, focus more on tooling and standards but ignore aspects of HTTP and can be more complex.

2. Web Services
Web Service API : 80
(Legacy) System

3. Web Services
Web Service API : 80
(Legacy) System

4. The Types of Web Services
Big Web Services
WS-Notification
REST
WS-Security
RPC style
WSDL
REST-RPC hybrid
SOAP
REST

5. RESTful Web Services

6. Representational State Transfer (REST) is a
style of software architecture for
distributed hypermedia systems such as the
World Wide Web. The term Representational
State Transfer was introduced and
defined in 2000 by Roy Fielding in his
doctoral dissertation. Fielding is one of
the principal authors of the Hypertext
Transfer Protocol (HTTP) specification
versions 1.0 and 1.1.

7. Bookings
Application HTTP Routes
Passengers

8. Resources
Bookings
Application HTTP Routes
Passengers

9. Resources
POST /booking/{id}/
GET
Application /route/{id}/
PUT
DELETE /passenger/{id}/

10. Addressable
Resources
POST /booking/{id}/
GET
Application /route/{id}/
PUT
DELETE /passenger/{id}/

11. Uniform Addressable
Interface Resources
POST /booking/{id}/
GET
Application /route/{id}/
PUT
DELETE /passenger/{id}/

12. Addressable
Resources
GET /booking/123/
/booking/{id}/
Application /route/{id}/
/passenger/{id}/

13. Addressable
Resources
GET /booking/123/
/booking/{id}/
Application /route/{id}/
/passenger/{id}/
State and
Representation

14. Addressable
Resources
GET /booking/123/
/booking/{id}/
Application /route/{id}/
200 OK
/passenger/{id}/
id: 123,
pickupTime: ‘2010-12-13T09:00:00’,
passenger: { State and
link: {
href: ‘/passenger/234’, Representation
rel: ‘related’
}
}

15. REST = HTTP Used Right
REST was “developed” in parallel with the HTTP/1.1
protocol
Caching and conditional GET
Proxies
HTTP headers (e.g.content negotiation)
HTTP methods

16. Everything Is a Resource
There shall be nothing else

17. Everything Is a Resource
ROA
There shall be nothing else

18. Everything Is a Resource
•Version 1.0.3 of the software release
•The latest version of the software release
•Search results for the word ‘Galactica’
•The next prime number after 1024
•The relationship between Alice and Bob
•A list of open bugs in the bug database
There shall be nothing else

19. Clean and Descriptive URIs

20. Clean and Descriptive URIs
/software/releases/1.0.3.tar.gz
/software/releases/latest.tar.gz
/search/Galactica
/nextprime/1024
/relationships/Alice;Bob
/bugs/by-state/open

21. State(lessness)
Application vs. Resource

22. The Uniform Interface

23. The Uniform Interface
GET - safe, idempotent
PUT - idempotent
DELETE - idempotent
POST - “complex”

24. The Uniform Interface
200 - OK
201 - Created
301 - Moved Permanently
400 - Bad Request
404 - Not Found
409 - Conflict
500 - Internal Server Error

25. Connectedness
passenger
booking
route

26. Hypermedia as the Engine
of Application State
passenger
booking
route

27. Problems?
Transactions
Asynchronous tasks
Batch jobs
Relationships between
resources
Partial updates
Partial representations

28. REST WS*
Embraces HTTP Ignores HTTP
No bandwidth overhead Good tool support
Simplicity WSDL
Web already is RESTful “Standards”
HTTPS / HTTP Diges, Plethora of Security
OAuth Standards

29. Why?