Learning_WebServices.txt

REST - REpresentational State Transfer  - No rules to be followed while creating.
SOAP - Set of rules which is needs to follow to create them - WSDL - Contract.
HTTP - Hyper Text Transfer Protocol

REST - Resource based URI - https://localhost:8080/employees/123 - URI /employees/{employeeID}
ContentTypes - text/xml, application/json

REST URI Types - 
                Instance Resource URI  - /employees/{employeeID} - identify specific type of resource
                Collections Resource URI - /employees - collecttion type URI - to create employee
                
Paging -  /emplooyees?offset=30&limit10 - Offset - StratingPoint

REST METHODS : GET, POST, DELETE, PUT 

PUT - update the message
POST - create new resource

Method IDEMPOTENCE

IDEMPOTENT - GET, DELETE, PUT - these are safe when we call mutiple times
NON - IDEMPOTENT - POST (Duplicate requests)

HTTP Codes : 200 - OK ,201 - Created ,204 - No Content
             302 - Found , 304 - Not modified 307 - Temporary 
             400 - Bad Request , 401 - Unauthorized , 403 - Forbidden , 404 - Not Found 
             500 - Internal Server Error
             
HATEOAS - HyperMedia As The Engine Of Application State  - providing the concurrent URL's in the main/first request like employeeAddress details like addressuri: "/employees/2/addresses"           

"links" : [
            {
              "href" : "/employees/1",
              "rel" : "self"
            }
            
             {
              "href" : "/employees/1",
              "rel" : "addresses"
            }
            {
              "href" : "/employees/1",
              "rel" : "worklocations"
            }
          ]

Richardson Maturity Model - There are 3  level
        Level One - Swap of POX (Plain Old XML) - SOAP - individual URI for resource
        Level Two - Usage of HTTP methods and status codes
        Level Three - Response have links that clients can use
        
        
REST Library - "JAX-RS" - javax.ws.rs* - Jersey library - Reference Implementation