ProblemNET is a middleware library that implements rfc7807. The middleware catches all exceptions and handles according to exception type.
For more information: https://tools.ietf.org/html/rfc7807

Install-Package ProblemNet

public class Startup
{
 public void ConfigureServices(IServiceCollection services)
 {
 services.AddProblemDetails(cfg => { cfg.DefaultTypeBaseUri = "https://sample.com/problemdetails/"; });
 services.AddMvc().
 UseProblemDetailsInvalidModelStateResponseFactory();
 }
 public void Configure(IApplicationBuilder app)
 {
 app.UseProblemDetailsExceptionHandler();
 ..
 ..
 ...
 }
}

There are different ways to create problems.

• Simple

   throw new ProblemDetailsException()
   {
   Type = "user-not-exists",
   Title = "User Not Exists",
   Status = (int)HttpStatusCode.NotFound,
   Detail = "Users cannot be found"
   };

  Will produce this response

   "type": "https://userservice.com/problemdetails/user-not-exists",
   "title": "User Not Exists",
   "status": 404,
   "detail": "Users cannot be found",
   "instance": "/api/Samples/problem-details-simple"

• Additional Members

   throw new ProblemDetailsException
   {
   Status = (int)HttpStatusCode.NotFound,
   Title = $"Users cannot be found",
   Extensions =
   {
   new KeyValuePair<string, object>("Order", new { OrderId = 1, OrderDate = DateTime.UtcNow, Status = "Approved" }),
   new KeyValuePair<string, object>("UserId", 123)
   }
   };

  Will produce this

   "type": "https://userservice.com/problemdetails/",
   "title": "Users cannot be found",
   "status": 404,
   "instance": "/api/Samples/problem-details-additional-members",
   "order": {
   "orderId": 1,
   "orderDate": "2019年09月07日T14:24:45.1783264Z",
   "status": "Approved"
   },
   "userId": 123

• Custom Validation Exception

  var validationProblems = new List<ValidationProblem>
   {
   new ValidationProblem("FirstName", "FirstName length must be less than 50 characters", "FirstName should only contain letters"),
   new ValidationProblem("Email", "Email address length must be greater than 5 characters", "Email address must be email format")
   };
  throw new ValidationProblemDetailsException(validationProblems.ToArray())
   {
   Detail = "Error while creating account. Please see errors for detail.",
   Status = (int)HttpStatusCode.BadRequest,
   Title = "Register Error"
   };
   

  Will produce this

   ```

• Exceptions Except Problem Details

  throw new NullReferenceException();

  Will produce the following output. If the environment is development, the content of the exception property will not be empty.

   "exception": { },
   "type": "https://httpstatuses.com/500",
   "title": "Internal Server Error",
   "status": 500,
   "detail": "An error occurred while processing your request",
   "instance": "/api/Samples/unhandled-exception"
   ```

The same http response headers will be produced regardless of exception type on the lines below. Middleware also ensures that problem responses never cached.

 cache-control: no-cache, no-store, must-revalidate 
 content-type: application/problem+json; charset=utf-8 
 date: 2019年9月07日 14:03:55 GMT 
 expires: 0 
 pragma: no-cache 
 server: Kestrel 
 transfer-encoding: chunked