RESTful HATEOAS standards using Java based Katharsis
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The document explains RESTful APIs, emphasizing the use of HTTP methods (GET, POST, PUT, PATCH, OPTIONS, DELETE) and the concept of HATEOAS (Hypermedia as the Engine of Application State) for self-describing APIs. It discusses JSON API standards for requesting and modifying resources, while highlighting considerations like how requests and responses are structured. The 'bikeshed moment' concept illustrates how trivial issues can overshadow complex tasks, and Katharsis is introduced as an elegant, modular HATEOAS framework for Java based on JSON API standards.
![Filter/Sort/Group/Pagination
• GET /api/tasks?filter[tasks][name]=Make%20Coffee
• GET /api/tasks?sort[tasks][name]=asc
• GET /api/tasks?group[tasks]=name
• GET /api/tasks?include[tasks]=project
• GET /api/tasks?page[offset]=0&page[limit]=10](https://image.slidesharecdn.com/katharsis-160720022249/85/RESTful-HATEOAS-standards-using-Java-based-Katharsis-13-320.jpg)
![Pagination using Links
"links": {
"self": “http://example.com/articles/22“,
"first": “http://example.com/articles?page[offset]=0”
"prev": “http://example.com/articles?page[offset]=1”
"next": "http://example.com/articles?page[offset]=3",
"last": "http://example.com/articles?page[offset]=10"
}](https://image.slidesharecdn.com/katharsis-160720022249/85/RESTful-HATEOAS-standards-using-Java-based-Katharsis-14-320.jpg)
RESTful HATEOAS standards using Java based Katharsis
- 1. RESTful HATEOAS standards using Java based Katharsis
- 2. Keith D. Moore • Independent Software Consultant • KD Moore Consulting • http://www.kdmooreconsulting.com • keith@kdmooreconsulting.com • @keithdmoore94 • in/keithdmoore94
- 3. What is a RESTful API? An application program interface (API) that uses HTTP methods like GET, POST, PUT, PATCH, OPTIONS and DELETE to make requests and receive responses.
- 4. HTTP Methods for REST • GET - this is a read method (get all/get one) • POST - this is a create method • PUT - this is an update method (usually a full replacement) • PATCH - this is an update method (usually partial) • OPTIONS - typically used for preflight requests or metadata • DELETE - this a delete method
- 5. HATEOAS • (Hypermedia as the Engine of Application State) is a constraint of the REST application architecture. A hypermedia-driven site provides information to navigate the site's REST interfaces dynamically by including hypermedia links with the responses. • Allows a client to navigate a set of resources with very little documentation. • Allows for resource urls to change without impacting the client. • Essentially provides the ability to create a self-describing API
- 6. Parkinson's law of triviality is C. Northcote Parkinson's 1957 argument that members of an organization give disproportionate weight to trivial issues. He observed that a committee whose job was to approve the plans for a nuclear power plant spent the majority of its time on discussions about relatively minor but easy-to-grasp issues, such as what materials to use for the staff bike-shed, while neglecting the proposed design of the plant itself, which is far more important but also a far more difficult and complex task.
- 7. The Bikeshed moment • How are the requests/responses going to be formatted? • Are we going to use a PATCH method for full and partial updates? • What is the format for a pagination or sorting request? • How will requests be structured that act on resource relationships? • How will error responses be formatted?
- 8. JSON API to the rescue • JSON API is a specification for how a client should request that resources be fetched or modified, and how a server should respond to those requests. • http://jsonapi.org (there really is a specification for it) • Even has its own media type: application/vnd.api+json • Lots of MUST, MUST NOT, SHOULD, MAY, etc. • There are still some decisions to be made but this gives you a framework to make some of the more fine grained decisions. • Several implementations in a variety of languages. Both client-side and server-side.
- 9. REST URI’s • GET /api/tasks: returns all tasks • GET /api/tasks/1: returns the task with ID 1 • POST /api/tasks: creates a task with the data sent in the body • PATCH /api/tasks/1: updates the task with ID 1 with the data sent in the body (only send what you want to update) • DELETE /api/tasks/1: delete the task with ID 1 • OPTIONS /api/tasks: metadata about the member resource
- 10. Sample Response { "data": { "type": "articles", "id": "1", "attributes": { “title”: “Having fun with JSON”, “description”: “Explore the fun you can have with JSON.” }, "relationships": { "author": { "links": { "self": "/articles/1/relationships/author", "related": “/articles/1/author" } } } } }
- 11. atharsis • a Greek word meaning "cleansing" or “purging” • Elegant and powerful HATEOAS framework for Java based on the JSON API standard • Uses ResourceRepository and ResourceRelationshipRepository • Annotation based or interface based • Modular • Core • Spring • JAX-RS • Servlet • Vertx • Examples • Very few dependencies
- 12. Let’s look at Katharsis in Action
- 13. Filter/Sort/Group/Pagination • GET /api/tasks?filter[tasks][name]=Make%20Coffee • GET /api/tasks?sort[tasks][name]=asc • GET /api/tasks?group[tasks]=name • GET /api/tasks?include[tasks]=project • GET /api/tasks?page[offset]=0&page[limit]=10
- 14. Pagination using Links "links": { "self": “http://example.com/articles/22“, "first": “http://example.com/articles?page[offset]=0” "prev": “http://example.com/articles?page[offset]=1” "next": "http://example.com/articles?page[offset]=3", "last": "http://example.com/articles?page[offset]=10" }
- 15. References and Links • http://jsonapi.org • https://en.wikipedia.org/wiki/HATEOAS • http://katharsis.io • https://en.wikipedia.org/wiki/Law_of_triviality