REST is architectural style developed in parallel to the HTTP/1.1 protocol
The largest known implementation of a system conforming to the REST architectural style is the Web
It is possible to design a software system in accordance with Fielding's REST architectural style without using HTTP and without interacting with the World Wide Web
REST in short
REST is more like style of programming
Best example of REST is RSS
REST is KISS
Why Representational State Transfer?
If user go to www.milosev.com
he will get the web page (Representational)
browser will change his page (State)
if user click on a link he will change (Transfer) browser state
Concept
Consists of clients and servers
It doesn't use resources on a network or server
example: web page, user can use web page, without sending messages to the server
Client sends messaged to the server only when it goes to new state
Constraints
Client - server
clients are not concerned with data storage
servers are not concerned with the user interface or user state
Stateless
each request from any client contains all of the information necessary to service the request, and any state is held in the client
Cacheable
well-managed caching partially and completely eliminates some client-server interactions, further improving scalability and performance
Uniform interface
simplifies and decouples the architecture
principles:
individual resources are identified in requests
manipulation of resources through these representations
self descriptive messages
hypermedia as the engine of application state
Layered system
a client cannot ordinarily tell whether it is connected directly to the end server, or to an intermediary along the way
Code on demand (optional)
Servers are able to transfer logic to the client that it can execute (example: JavaScript)
Resources
An important concept in REST is the existence of resources
Client doesn't know is there cache, proxy, firewall, or anything else between client or server
Client must know format of the information which is back
