Spring-boot-web-rest

This is a Spring Boot application for Web based REST

Featuriz guide to Spring Framework 5.

Technology and Version

Spring	Version
Spring Boot	2.6.1
Spring web	5.3.13
Spring Test	5.3.13
Spring JPA	2.6.1
Mariadb	2.7.4
Lombok	1.18.22
Validation	2.6.1

How to use

This is a maven based spring boot project. Use maven to build this project and just run.
No other dependencies

Database

Check application.properties file.

• Entities can create tables
• You can add mock content to db by using data.sql file - This can be load automatically, check properties file.

Based on

This work is based on the tutorial from
Building REST services with Spring

Learning topics

The difference between REST and RPC:

• REST - Representational State Transfer
• RPC - Remote Procedure Call

Spring HATEOAS

Working with Spring HATEOAS

• This helps to write hypermedia-driven outputs.

  org.springframework.boot spring-boot-starter-hateoas

• A critical ingredient to any RESTful service is adding links to relevant operations

  { "id": 1, "name": "Bilbo Baggins", "role": "burglar", "_links": { "self": { "href": "http://localhost:8080/employees/1" }, "employees": { "href": "http://localhost:8080/employees" } } }

Simplifying Link Creation

• Create EmployeeModelAssembler by implementing RepresentationModelAssembler interface
• Convert Employee objects to EntityModel objects

Evolving REST APIs

Never delete a column in a database. 

• Replace the field
• A "virtual" getter & setter for the old name property

Proper Responses

• Include a Location response header

• Return the model-based version of the saved object

  $ curl -v -X PUT localhost:8080/employees/3 -H 'Content-Type:application/json' -d '{"name": "Samwise Gamgee", "role": "ring bearer"}'

  • TCP_NODELAY set
  • Connected to localhost (::1) port 8080 (#0)

  PUT /employees/3 HTTP/1.1 Host: localhost:8080 User-Agent: curl/7.54.0 Accept: / Content-Type:application/json Content-Length: 49

  < HTTP/1.1 201 < Location: http://localhost:8080/employees/3 < Content-Type: application/hal+json;charset=UTF-8 < Transfer-Encoding: chunked < Date: Fri, 10 Aug 2018 19:52:56 GMT { "id": 3, "firstName": "Samwise", "lastName": "Gamgee", "role": "ring bearer", "name": "Samwise Gamgee", "_links": { "self": { "href": "http://localhost:8080/employees/3" }, "employees": { "href": "http://localhost:8080/employees" } } }

Building links into your REST API

• Enter HATEOAS or Hypermedia as the Engine of Application State.
• Instead of clients parsing the payload, give them links to signal valid actions.
• Decouple state-based actions from the payload of data.
• In other words, when CANCEL and COMPLETE are valid actions, dynamically add them to the list of links.
• Clients only need show users the corresponding buttons when the links exist.

Try cancelling an order:

$ curl -v -X DELETE http://localhost:8080/orders/4/cancel
> DELETE /orders/4/cancel HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.54.0
> Accept: */*
>
< HTTP/1.1 200
< Content-Type: application/hal+json;charset=UTF-8
< Transfer-Encoding: chunked
< Date: Mon, 27 Aug 2018 15:02:10 GMT
<
{
  "id": 4,
  "description": "iPhone",
  "status": "CANCELLED",
  "_links": {
    "self": {
      "href": "http://localhost:8080/orders/4"
    },
    "orders": {
      "href": "http://localhost:8080/orders"
    }
  }
}

HTTP 200 status code indicating it was successful

If you try the same operation again…

$ curl -v -X DELETE http://localhost:8080/orders/4/cancel

* TCP_NODELAY set
* Connected to localhost (::1) port 8080 (#0)
> DELETE /orders/4/cancel HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.54.0
> Accept: */*
>
< HTTP/1.1 405
< Content-Type: application/problem+json
< Transfer-Encoding: chunked
< Date: Mon, 27 Aug 2018 15:03:24 GMT
<
{
  "title": "Method not allowed",
  "detail": "You can't cancel an order that is in the CANCELLED status"
}

HTTP 405 Method Not Allowed