Custom Exception Middleware

Install

• Package Manager Console

Install-Package CustomExceptionMiddleware

• .Net CLI

dotnet add package CustomExceptionMiddleware

Minimum requirements to use: .NET Standard 2.0

Compilation requirements: .NET 5

How to use

It's very simple to use, go to Startup.cs on Configure() method and add this code:

app.UseCustomExceptionMiddleware();

Example output

{
    "ErrorMessage": "Custom not found exception message"
}

Custom use

1. Create object options
   It's possible create a CustomExceptionOptions to customize the return middleware object, to create this options add this:

   app.UseCustomExceptionMiddleware(new CustomExceptionOptions
   {
       CustomErrorModel = new
       {
           Success = false
           Type = "ErrorType"
       }
   });

   Example output

   {
       "Type": "TestType",
       "Success": false,
       "ErrorMessage": "Custom not found exception message"
   }
   

2. Use an action options
   Other options to customize the return object is using an action to create a CustomErrorModel

   app.UseCustomExceptionMiddleware(options =>
   {
       options.CustomErrorModel = new
       {
           Success = false
           Type = "ErrorType"
       };
   });

   Example output

   {
       "Type": "TestType",
       "Success": false,
       "ErrorMessage": "Custom not found exception message"
   }
   

Configure Exceptions

This middleware use some custom exceptions to catch and personalize the response status code.

The custom middleware supports the following Exceptions:

Exception	Status code description	Status code
DomainException	BadRequest	400
CannotAccessException	Forbidden	403
NotFoundException	NotFound	404
Exception	InternalServerError	500

DomainException is an abstract exception, so to use it's necessary create other exception and inherit. The others exceptions only throw an exception

Custom exception example

public class InvalidStateException : DomainException
{
    public InvalidStateException(string message) : base(message)
    { }
}

Throw exceptions

throw new InvalidStateException("Custom domain exception message");
throw new CannotAccessException("Custom cannot access exception message");
throw new NotFoundException("Custom not found exception message");
throw new Exception("Custom exception message");