.NET: Add Global Exception Handler to .NET Core Razor Pages

The following can be added to your Startup.cs file as a global exception handler. From here, you can grab the exception and do...whatever you want with it. I wrapped the exception logic in a try catch just to ensure we don't throw a new unhandled exception.

copy

app.UseExceptionHandler(exceptionHandlerApp =>
{
	exceptionHandlerApp.Run(async context =>
	{
		//being extra careful with the try catch to not throw exception in exception handler
		try
		{
			var ex = context.Features.Get<IExceptionHandlerFeature>();
			if (ex != null && ex.Error != null)
			{
				//do someting with the error
			}
		}
		catch (Exception ex)
		{ 
			//don't do anything here but maybe add a breakpoint to understand if you enounter an additional error
		}

		
		//return a 500 response code
		context.Response.StatusCode = StatusCodes.Status500InternalServerError;

		//return plain text content
		context.Response.ContentType = Text.Plain;

		//return simple text response
		await context.Response.WriteAsync("An exception was thrown.");

		////if you want to check for an error related to the request path
		//var exceptionHandlerPathFeature = context.Features.Get<IExceptionHandlerPathFeature>();
		//if (exceptionHandlerPathFeature?.Error is FileNotFoundException)
		//{
		//    await context.Response.WriteAsync(" The file was not found.");
		//}
		//if (exceptionHandlerPathFeature?.Path == "/")
		//{
		//    await context.Response.WriteAsync(" Page: Home.");
		//}		
	});
});