Handling Exceptions Separately in ASP.NET Core: MVC and Web API Controllers

Learn how to effectively manage separate exception handling flows for `MVC` and `Web API` controllers in a single ASP.NET Core application using custom middleware.
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Handling Exceptions Separately in ASP.NET Core: MVC and Web API Controllers

In the world of web development, effectively managing errors and exceptions is crucial for providing a seamless user experience. However, when working with a single ASP.NET Core MVC application that houses both MVC and Web API controllers, configuring distinct exception handling flows can be quite challenging. If you've faced this issue, you're not alone! Let's dive into how to implement separate exception handling strategies for your MVC and API components.

Problem Overview

In an ASP.NET Core application, it's essential to handle errors correctly and distinctly for different types of controllers. For example, when an MVC controller encounters an error, you'd want to render an error view, while for Web API controllers, the preferred approach is usually to return a JSON response that can be processed on the client side.

The challenge arises when both types of controllers are mixed within a single application. You may find it difficult to configure your error handling system so that:

MVC exceptions display user-friendly error pages.

API exceptions return clear, structured JSON error responses.

Solution: Using Middleware to Handle Exceptions Differently

To achieve this, we can utilize ASP.NET Core's middleware capabilities. The MapWhen method provides a powerful way to route requests and apply specific handling based on the request path. Below are the steps to implement this logic:

Step 1: Define Custom Exception Middleware

Before we can handle exceptions separately, we need to create two custom middleware classes: ApiExceptionMiddleware for handling API exceptions and MvcExceptionMiddleware for MVC exceptions.

Example:

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Step 2: Integrate Middleware into the Application Pipeline

Example:

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Step 3: Utilize the Error Handlers in Your Controllers

Now that we have our middleware set up, we can throw exceptions from both the MVC controllers (HomeController) and Web API controllers (CustomersController). The exceptions will be routed correctly based on the type of controller and processed by the corresponding middleware.

Sample Web API Controller:

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Sample MVC Controller:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By utilizing the MapWhen method and implementing custom exception middleware, you can easily manage error flows separately for your MVC and Web API controllers in a single ASP.NET Core application. This not only improves user experience but also enhances the maintainability of your code.

Implement these patterns in your next project to ensure a robust and user-friendly error-handling system! Happy coding!