H.A.T.E.O.A.S example

Suppose you have an e-commerce website with the following resources:

1. GET /products - Returns a list of products.
2. GET /products/{id} - Returns a specific product by ID.
3. POST /orders - Creates a new order.
4. GET /orders - Returns a list of all orders.
5. GET /orders/{id} - Returns a specific order by ID.

To implement HATEOAS in this API, each response should include links to related resources that the client can navigate to. For example:

1. GET /products - Returns a list of products, each with a link to the product's details:

   {
       "products": [
           {
               "id": 1,
               "name": "Product 1",
               "description": "Product 1 description",
               "price": 9.99,
               "_links": {
                   "self": {
                       "href": "/products/1"
                   }
               }
           },
           {
               "id": 2,
               "name": "Product 2",
               "description": "Product 2 description",
               "price": 19.99,
               "_links": {
                   "self": {
                       "href": "/products/2"
                   }
               }
           }
       ],
       "_links": {
           "self": {
               "href": "/products"
           }
       }
   }
   

2. GET /products/{id} - Returns a specific product by ID, with links to related resources:

   {
       "id": 1,
       "name": "Product 1",
       "description": "Product 1 description",
       "price": 9.99,
       "_links": {
           "self": {
               "href": "/products/1"
           },
           "order": {
               "href": "/orders",
               "method": "POST",
               "title": "Order Product 1"
           }
       }
   }
   

   In this example, the product details include a link to create a new order for this product, via a POST /orders request.

3. POST /orders - Creates a new order, with a link to the newly-created order:

   {
       "id": 123,
       "product_id": 1,
       "quantity": 1,
       "_links": {
           "self": {
               "href": "/orders/123"
           },
           "product": {
               "href": "/products/1"
           }
       }
   }
   

4. GET /orders - Returns a list of all orders, each with a link to the order's details:

   {
       "orders": [
           {
               "id": 123,
               "product_id": 1,
               "quantity": 1,
               "_links": {
                   "self": {
                       "href": "/orders/123"
                   }
               }
           },
           {
               "id": 124,
               "product_id": 2,
               "quantity": 2,
               "_links": {
                   "self": {
                       "href": "/orders/124"
                   }
               }
           }
       ],
       "_links": {
           "self": {
               "href": "/orders"
           }
       }
   }
   

5. GET /orders/{id} - Returns a specific order by ID, with links to related resources:

   {
       "id": 12345,
       "customer": {
           "id": 54321,
           "name": "John Smith"
       },
       "items": [
           {
               "id": 1,
               "name": "Product A",
               "price": 9.99,
               "quantity": 2,
               "links": [
                   {
                       "rel": "self",
                       "href": "/products/1"
                   }
               ]
           },
           {
               "id": 2,
               "name": "Product B",
               "price": 14.99,
               "quantity": 1,
               "links": [
                   {
                       "rel": "self",
                       "href": "/products/2"
                   }
               ]
           }
       ],
       "total": 34.97,
       "status": "delivered",
       "links": [
           {
               "rel": "self",
               "href": "/orders/12345"
           },
           {
               "rel": "customer",
               "href": "/customers/54321"
           }
       ]
   }