Representational State Transfer

1. Representational State Transfer (REST)
 : Architectural style that parallels and informs the design of HTTP/1.1

2. REST Constraints
 1) Client-Server: Separation of concerns, user interface and data storage
  (+) improves portability of user interface, improves scalability by simplifying server
 2) Stateless: no context is stored on the server
  (+) improves visibility, reliability, scalability
  (-) increases overhead
 3) Cache
  (+) allows some interactions to be eliminated and reduces average latency
  (-) stale data reduces reliability
 4) Layered system
  (+) improves scalability (load balancing)
  (-) adds latency and overhead
 5) Uniform Interface
  (+) encourages independent evolvability
  (-) Degrades efficiency
 6) Code on demand (optional)

http://whatisrest.com/rest_constraints/index

3. Architectural Elements
 - Data Elements: Resources / Resource identifiers / Representations / Representation metadata / Control data
 - Connectors: Client / Server / Cache / Resolver / Tunnel
 - Components: Origin server / Gateway / Proxy / User agent

http://www.ics.uci.edu/~fielding/pubs/dissertation/top.htm

4. Introduction to RESTful Web Service
 1) The Richardson Maturity Model: Model of RESTful maturity

Level Zero	Level One	Level Two	Level Three
Single well-known endpoint	Multiple endpoints	Multiple endpoints, identifying resources	Multiple endpoints, identifying resources
uses HTTP as only transport	uses HTTP as only transport	understands HTTP	understands HTTP
No hypermedia	No hypermedia	No hypermedia	uses links to communicate protocols

https://martinfowler.com/articles/richardsonMaturityModel.html

2) HATEOAS: Hypermedia As The Engine Of Application State

https://medium.freecodecamp.com/restful-services-part-iii-hateoas-and-the-richardson-maturity-model-48d4e4c79b8d#.vdqz8mwh3