JSON exception throwback

Question

I am developing an API with ASP.NET Kernel and I am struggling with exception handling.

If any exception occurs or on any controller where I want to return user errors with different status codes, I want to return exception reports in JSON format. I don’t need the HTML in the error answers.

I'm not sure if I need to use middleware or anything else for this. How should I return JSON exceptions in the ASP.NET API?

Answer 1

Well, I have a working solution that I am very satisfied.

• : Configure ( ASP.NET).

  public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
  {
      // logging stuff, etc.
  
      app.UseStatusCodePagesWithReExecute("/error/{0}");
      app.UseExceptionHandler("/error");
  
      app.UseMvc(); // if you are using Mvc
  
      // probably other middleware stuff 
  }
  

• , JSON, :

  public class ExceptionMessageContent
  {
  
      public string Error { get; set; }
      public string Message { get; set; }
  
  }
  

• , . , .

  [Route("[controller]")]
  public class ErrorController : Controller
  {
  
      [HttpGet]
      [Route("")]
      public IActionResult ServerError()
      {
  
          var feature = this.HttpContext.Features.Get<IExceptionHandlerFeature>();
          var content = new ExceptionMessageContent()
          {
              Error = "Unexpected Server Error",
              Message = feature?.Error.Message
          };
          return Content( JsonConvert.SerializeObject( content ), "application/json" );
  
      }
  
  
      [HttpGet]
      [Route("{statusCode}")]
      public IActionResult StatusCodeError(int statusCode)
      {
  
          var feature = this.HttpContext.Features.Get<IExceptionHandlerFeature>();
          var content = new ExceptionMessageContent() { Error = "Server Error", Message = $"The Server responded with status code {statusCode}" };
          return Content( JsonConvert.SerializeObject( content ), "application/json" );
  
      }
  }
  

, , . 500 . , 404 . , , ExceptionMessageContent, :

// inside controller, returning IActionResult

var content = new ExceptionMessageContent() { 
    Error = "Bad Request", 
    Message = "Details of why this request is bad." 
};

return BadRequest( content );

Answer 2

( , ) - , . docs:

, , . , . .

JSON, :

public class JsonExceptionFilter : IExceptionFilter
{
    public void OnException(ExceptionContext context)
    {
        var result = new ObjectResult(new
        {
            code = 500,
            message = "A server error occurred.",
            detailedMessage = context.Exception.Message
        });

        result.StatusCode = 500;
        context.Result = result;
    }
}

, , . ObjectResult JSON.

MVC Startup:

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc(options =>
    {
        options.Filters.Add(typeof(JsonExceptionFilter));
    });
}