- Restful webservices are services that follow the REST architectural style, using HTTP methods like GET, POST, PUT, PATCH, and DELETE to operate on resources identified by URIs. Resources are data entities and representations that are manipulated via their URIs and representations. A restful API should expose resources and operations on them through URI endpoints and HTTP methods instead of exposing methods directly. This document discusses the history of REST, defines key REST concepts like resources and URIs, and provides examples of how to design RESTful APIs and endpoints for resources and collections of resources.

1. Restful webservices design
Ahmed Elbassel
Email: elbassel.n13@gmail.com
Skype: ahmed_elbassel

2. Restful Webservices
- History
- What is webservices?
- Resource-Oriented Architecture
- HTTP methods
- Restful API design
- References

3. History
- Before 1999, people used to use SOAP to
integrate APIs.
- In 2000, REST was defined by Roy
Fielding in his PhD dissertation
"Architectural Styles and the Design of
Network-based Software Architectures"

4. History
- Properties:
- Scalability: to support large numbers of components and interactions among components.
- Simplicity of a Uniform Interface
- Modifiability of components to meet changing needs (even while the application is running)
- Portability of components by moving program code with the data
- Constraints:
- Client-Server
- Stateless: Each request from any client contains all the information necessary to service the
request
- Cacheable: Responses must, implicitly or explicitly, define themselves as cacheable, or not, to
avoid unsuitable response.
- Layered System: A client cannot ordinarily tell whether it is connected directly to the end
server, or to an intermediary along the way.

5. What is Restful Webservices?
- Representational state transfer (REST) or RESTful Web services are one way
of providing interoperability between computer systems on the Internet.
- Fielding used REST to design HTTP 1.1

6. Resource-Oriented Architecture
- In software engineering, a resource-oriented architecture (ROA) is a style of
software architecture and programming paradigm for designing and
developing software in the form of resources with "RESTful" interfaces.

7. HTTP methods
- HTTP implements REST, and we’re using HTTP to provide our restful
webservices.
HTTP Method Operation Note
POST Create It creates a new instance, it returns 201 code
PUT Update/Replace It updates or replaces the entire instance, it returns 200.
GET Read It reads from the server, it returns http code 200
PATCH Update/Modify It updates specific thing inside the instance, it returns 200
DELETE Remove It removes an instance, it returns 200

8. Restful API design
- It’s all about resources, REST tries to make every resource is a unique
location.
- URI: is used to locate the resource.
- To get tulip1 image in hard drive: /images/tulip1.jpg

9. Restful API design
Suppose we have the following Object:
User
Name: String
SSN: String
Job: String
addresses:
Address
Street: String
Building: String
Apartment: String

10. Restful API design - Moving from Verbs to Nouns
- Old API: getUser.
- Verb (get) + resource name(User)
- Old API: createUser.
- Verb(create) + resource name(User)
- Old API: deleteUser.
- Verb(delete) + resource name(User)
- Old API: updateUser.
- Verb(update) + resource name(user)
- HTTP provides the method name, your turn to provide the resource name:
- GET: /User/userId
- POST: /User
- DELETE: /User/userId
- PUT: /User/userId

11. Restful API design - More
- Old API: getUserAddress.
- Verb (get) + resource name(UserAddress)
- Old API: createUserAddress.
- Verb(create) + resource name(UserAddress)
- Old API: deleteUserAddress.
- Verb(delete) + resource name(UserAddress)
- Old API: updateUserAddress.
- Verb(update) + resource name(userAccont)
- HTTP provides the method name, your turn to provide the resource name:
- GET: /User/userId/addresses
- POST: /user/userId/addresses
- DELETE: /user/userId/adresses/id
- PUT: /User/userId/adresses

12. References
https://msdn.microsoft.com/en-us/library/dd203052.aspx
https://en.wikipedia.org/wiki/Resource-oriented_architecture
https://en.wikipedia.org/wiki/Representational_state_transfer