Implement Global Exception Handling Middleware in .NET Project

Introduction

In building software with .NET, it's super important to handle errors effectively. Think of it like catching mistakes before they turn into big problems! One Smart way to do this is using Global Exception Handling as a middleware. It basically helps keep track of errors all over your project. This article will show you how to set up and use middleware to handle errors in your .NET project, making your software more reliable and less likely to crash. and it'll save you from writing the same code over and over again.

What is Global Exception Handling?

Global Exception Handling is like having a special safety net in your software. When something unexpected goes wrong (like a mistake or a problem), instead of crashing your whole program, it catches the problem and deals with it calmly. It's a way to handle errors smoothly, making sure your software keeps running smoothly even when things don't go as planned.

Integrate the Middleware for Exception Handling

Let's integrate the Middleware for Exception Handling in the .NET Project.

First, you need to add a class in your project named GlobalExceptionHandler.cs and write this code inside this class.

 public class GlobalExceptionHandler:IExceptionFilter
 {
     private readonly IHostEnvironment _hostEnvironment;
     private readonly ILoggerRepo? _loggerRepo;
     
     public GlobalExceptionHandler(IHostEnvironment hostEnvironment, ILoggerRepo loggerRepo)
     {
         _hostEnvironment = hostEnvironment;
         _loggerRepo = loggerRepo;
     }

     public void OnException(ExceptionContext context)
     {
         if (!_hostEnvironment.IsDevelopment())
         {
             // Don't display exception details unless running in Development.
             return;
         }
         var errorObject = new
         {
             ErrorObject = new
             {
                 Status = Convert.ToInt32(ConstantAndEnum.Status.Error),
                 ErrorCode = Convert.ToInt32(ConstantAndEnum.ErrorCode.General),
                 ErrorMessage = CommonMethods.GetErrorMesage("GeneralError.AnErrorOccured")
             }

         };
         context.Result = new JsonResult(errorObject);
     }
}

Code Explanation

• GlobalExceptionHandler is a class name and this class implemented the IExceptionFilter interface indicating that it will handle exceptions thrown during the execution of the application.
• The GlobalExceptionHandler class has a constructor that takes two parameters: `IHostEnvironment` and `ILoggerRepo`.
• IHostEnvironment typically provides information about the hosting environment (like Development, Production, etc.).
• ILoggerRepo seems to be a logger repository, probably an abstraction over logging functionality.
• OnException method is part of the `IExceptionFilter` interface and is called whenever an exception occurs during the execution of a controller action and method begins by checking if the application is running in a development environment. If not, it skips handling the exception details. If the application is running in development mode, it proceeds to handle the exception.

Then, we need to add a service for this middleware in the program.cs file.

builder.Services.AddScoped<GlobalExceptionHandler>(); //GlobalExceptionHandler is class name
var app = builder.Build();
app.ConfigureMiddleware();

Now that you've removed the try-catch block from your method, the method will be automatically invoked whenever an error occurs without the need for a try-catch block. After running the project and integrating this functionality into my API project, this type of response is generated when an error occurs.

And getting this API response as an ErrorObject when the exception occurs.

Conclusion

Implementing Global Exception Handling as middleware in a .NET project offers a robust approach to error management, ensuring smoother application operation even in the face of unexpected issues. By centralizing error handling and avoiding repetitive try-catch blocks, developers can enhance the reliability and stability of their software, ultimately delivering a more resilient user experience.

FAQs

Q 1. Why is Global Exception Handling important in .NET development?

Ans. Global Exception Handling acts as a safety net, preventing application crashes by gracefully handling unexpected errors. It ensures smoother operation and enhances software reliability, especially in production environments.

Q 2. How does Global Exception Handling differ from local exception handling?

Ans. While local exception handling addresses errors within a specific code block, Global Exception Handling intercepts exceptions across the entire application. This centralized approach streamlines error management and promotes consistent handling practices.

Q 3. Can Global Exception Handling be customized for different environments?

Ans. Yes, Global Exception Handling can be tailored based on the application's environment, such as development, staging, or production. This flexibility allows developers to adjust error-handling behavior according to specific deployment scenarios.

Q 4. What is the Global Exception Handling in .NET?

Ans. Global Exception Handling is like having a special safety net in your software. When something unexpected goes wrong (like a mistake or a problem), instead of crashing your whole program, it catches the problem and deals with it calmly.

Q 5. How does Global Exception Handling contribute to code maintainability?

Ans. By centralizing error handling logic, Global Exception Handling reduces code duplication and promotes cleaner, more maintainable codebases. Developers can focus on implementing business logic while ensuring consistent error-handling practices throughout the application.