Handling Errors in Web API Using Exception Filters and Exception Handlers

ExceptionHandlers.cs

public override void OnException(HttpActionExecutedContext actionExecutedContext)

ExceptionHandlers2.cs

public class DivideByZeroExceptionFilter : ExceptionFilterAttribute
{
public override void OnException(HttpActionExecutedContext actionExecutedContext)
{
if (actionExecutedContext.Exception is DivideByZeroException)
{
actionExecutedContext.Response = new HttpResponseMessage()
{ Content = new StringContent("We apologize but an error occured within the application. Please try again later.", System.Text.Encoding.UTF8, "text/plain"), StatusCode = System.Net.HttpStatusCode.InternalServerError};
}
}

}

ExceptionHandlers3.cs

[DivideByZeroExceptionFilter]
public void Delete(int id)
{
throw new DivideByZeroException();
}

ExceptionHandlers4.cs

config.Filters.Add(new DivideByZeroExceptionFilter());

ExceptionHandlers5.cs

//A global exception handler that will be used to catch any error
public class MyExceptionHandler : ExceptionHandler
{
//A basic DTO to return back to the caller with data about the error
private class ErrorInformation
{
public string Message { get; set; }
public DateTime ErrorDate { get; set; }
}

public override void Handle(ExceptionHandlerContext context)
{

//Return a DTO representing what happened
context.Result = new ResponseMessageResult(context.Request.CreateResponse(HttpStatusCode.InternalServerError,
new ErrorInformation { Message="We apologize but an unexpected error occured. Please try again later.", ErrorDate=DateTime.UtcNow }));

//This is commented out, but could also serve the purpose if you wanted to only return some text directly, rather than JSON that the front end will bind to.
//context.Result = new ResponseMessageResult(context.Request.CreateResponse(HttpStatusCode.InternalServerError, "We apologize but an unexpected error occured. Please try again later."));
}
}

ExceptionHandlers6.cs

config.Services.Replace(typeof(IExceptionHandler), new MyExceptionHandler());