Specifying the API

The very first thing a project usually starts with is a definition of the operations the API will expose. According to the REST principles, an operation is exposed by an HTTP method and a URI. The action performed by each operation should not contradict the natural meaning of its HTTP method. The following table specifies the operations of our API in detail:

Method	URI	Description
GET	/category	Retrieves all available categories in the catalog.
GET	/category/{category-id}/	Retrieves all the items available under a specific category.
GET	/category/{category-id}/{item-id}	Retrieves an item by its ID under a specific category.
POST	/category	Creates a new category; if it exists, it will update it.
POST	/category/{category-id}/	Creates a new item in a specified category. If the item exists, it will update it.
PUT	/category/{category-id}	Updates a category.
PUT	/category/{category-id}/{item-id}	Updates an item in a specified category.
DELETE	/category/{category-id}	Deletes an existing category...