Program.cs

usingMicrosoft.AspNetCore.Mvc;
usingSystem.Net;
usingMicrosoft.AspNetCore.Mvc.ModelBinding;
usingMicrosoft.AspNetCore.Http.Extensions;

varbuilder=WebApplication.CreateBuilder();
builder.Services.AddControllersWithViews();

varapp=builder.Build();
app.UseRouting();
app.MapControllers();
app.Run();

[ApiController]
publicclassHomeController:Controller
{
[HttpGet("")]
publicActionResult<string>Index()
{
try
{
thrownewApplicationException("Catch this one");
}
catch(Exceptionex)
{
returnthis.ApiProblemDetails(HttpStatusCode.InternalServerError,exception:ex);
}
}
}




publicclassApiProblemsDetails:ProblemDetails
{
publicstringRequestPath{get;set;}

publicobjectRequestPayload{get;set;}

publicIReadOnlyDictionary<string,string>ValidationMessages{get;set;}=newDictionary<string,string>();

publicstringStackTrace{get;set;}
}

publicstaticclassControllerExtensions
{
publicstaticActionResultApiProblemDetails(thisControllerself,HttpStatusCodestatusCode,
stringtitle="",
stringdetail="",
IReadOnlyDictionary<string,string>validationMessages=null,
ModelStateDictionarymodelState=null,
Exceptionexception=null,
objectrequest=null)
{
vardetails=newApiProblemsDetails
{
Title=title,
Detail=detail,
RequestPath=self.Request.GetDisplayUrl(),
Status=(int)statusCode
};

if(validationMessages!=null)
details.ValidationMessages=validationMessages;

if(modelState!=null)
{
varmodelStateMessages=modelState
.Where(x =>x.Value.Errors.Count>0)
.ToDictionary(
 kvp =>kvp.Key,
 kvp =>string.Join(",",kvp.Value.Errors.Select(e =>e.ErrorMessage).ToArray())
);

if(details.ValidationMessages==null)
details.ValidationMessages=modelStateMessages;
else
details.ValidationMessages=details.ValidationMessages.Union(modelStateMessages).ToDictionary(x =>x.Key, x =>x.Value);
}

varhost=self.HttpContext.RequestServices.GetService(typeof(IWebHostEnvironment))asIWebHostEnvironment;

if(exception!=null&&host.EnvironmentName==Environments.Development)
{
if(string.IsNullOrWhiteSpace(details.Detail))
details.Detail="Exception Message: "+exception.Message;
else
details.Detail+="\n\n Exception Message: "+exception.Message;

details.StackTrace=exception.StackTrace;
}

if(request!=null)
details.RequestPayload=request;

returnself.StatusCode((int)statusCode,details);
}
}