Overview

This endpoint follows Domain-Driven Design principles to retrieve a specific Book aggregate root from the Catalog bounded context by its unique identifier. The operation is implemented as a query that doesn’t modify state, adhering to CQRS patterns.

The query handler maps the domain entity to a BookDto response through an auto-mapper profile, ensuring that domain implementation details remain encapsulated. The endpoint respects the aggregate boundaries and only exposes data appropriate for the presentation layer.

If the requested book doesn’t exist, the service returns a Not Found response rather than a null object, following the Fail Fast principle.

This endpoint is also integrated with our distributed caching strategy to optimize read-heavy operations and reduce database load.

Architecture

Behavior

The endpoint implements the following behavior:

1. Validates the provided GUID format for the book ID
2. Queries the book repository to fetch the book entity
3. If the book is not found, returns a 404 Not Found response
4. Maps the domain entity to a DTO using the configured auto-mapper
5. Returns the book data with a 200 OK status code

Implementation Details

The endpoint is implemented using:

• CQRS pattern with a dedicated query handler
• Domain-Driven Design principles
• Repository pattern for data access
• Auto-mapping for entity-to-DTO conversion
• Proper error handling with domain-specific exceptions

GET (/api/v1/books/{id})

Parameters

• id (path) (required) - The unique identifier (GUID) of the book to retrieve

Request Body

No request body is required for this endpoint.

Example Usage

curl -X GET "https://api.bookworm.com/api/v1/books/0195e692-600b-715e-a17b-b3a8faf4ed07"

Responses

200 OK

404 Not Found

Returns when the requested book ID does not exist in the system.

Success Response

{
  "id": "0195e692-600b-715e-a17b-b3a8faf4ed07",
  "name": "The Great Gatsby",
  "description": "A classic novel by F. Scott Fitzgerald.",
  "imageUrl": "URL_ADDRESS.com/great-gatsby.jpg",
  "price": 10.99,
  "discountPrice": 9.99,
  "status": "InStock",
  "authors": [
    {
      "id": "0195e692-600b-7290-a47f-982b9d7f15f3",
      "name": "F. Scott Fitzgerald"
    },
    {
      "id": "0195e692-600b-7d32-99b0-ae7abd82a863",
      "name": "John Smith"
    }
  ],
  "category": {
    "id": "0195e692-600b-7424-a426-dac7227720fe",
    "name": "Fiction"
  },
  "publisher": {
    "id": "0195e692-600b-78b3-9b7f-3e342d9f2815",
    "name": "Scribner"
  },
  "averageRating": 4.5,
  "totalReviews": 100,
}

Error Response

{
  "type": "https://tools.ietf.org/html/rfc7231#section-6.5.4",
  "title": "Not Found",
  "status": 404,
  "detail": "Book with id 123e4567-e89b-12d3-a456-426614174000 not found."
}