Reducing Duplicate Code with Custom Action Filters
Action filters in ASP.NET Core are a way to encapsulate cross-cutting concerns, such as logging, exception handling, and authorization, that apply to multiple actions or controllers. By creating custom action filters, you can reduce duplicate code across your application and promote better code organization and reusability. This section will guide you on how to define and apply custom action filters.

Video: Reducing Duplicate Code with Custom Action Filters

Creating Explicit Contracts with Request Objects

Request objects, also known as Data Transfer Objects (DTOs), are simple classes that represent the data contract between client and server. They provide a clear, explicit contract for an API, and they can significantly clean up your code by separating the data sent in a request from the domain entities in your application. This part will delve into the creation and use of request objects in your ASP.NET Core application.

Video: Creating Explicit Contracts with Request Objects

Moving Business Logic from a Controller to a Service

In a well-structured ASP.NET Core application, controllers should be lean and focused on handling HTTP requests and responses. Business logic should be moved to services to promote a clear separation of concerns. This segment covers the process of refactoring a bloated controller by moving business logic to a dedicated service.

Video: Moving Business Logic from a Controller to a Service

Consuming a Service from a Controller

Once business logic is encapsulated into a service, it needs to be consumed by your controllers. This final video will demonstrate how to inject and use services in your controllers using the built-in dependency injection features of ASP.NET Core.

Video: Consuming a Service from a Controller

Key Takeaways:

• Custom action filters can encapsulate cross-cutting concerns to reduce duplicate code across an application.
• Request objects provide an explicit data contract between client and server, simplifying the interaction and ensuring data integrity.
• Moving business logic to a service separates concerns and keeps controllers lean, focused solely on handling HTTP requests and responses.
• Consuming services in controllers is made seamless with ASP.NET Core's built-in dependency injection features.