Understand the Complete API Architecture
Let's review how all application components work together.
The frontend sends an HTTP request to the Express server.
Global middleware handles security headers, CORS, and request parsing.
The router identifies the requested endpoint.
Validation middleware checks incoming data.
Authentication middleware verifies the JWT when required.
Authorization middleware checks permissions and resource ownership.
The controller invokes the service layer.
The service performs business logic and interacts with the Mongoose model.
Mongoose communicates with MongoDB and returns the result.
Finally, the controller sends a JSON response to the client.
The centralized error middleware handles unexpected errors throughout the application.
The application follows a layered architecture.
Middleware handles cross-cutting request concerns.
Services contain business logic.
Mongoose provides database access.
Centralized error handling provides consistent responses.