Add Response Headers to ASP.NET Core Middleware

Question

I want to add a processing time middleware to my ASP.NET Core WebApi like this

public class ProcessingTimeMiddleware  
{
    private readonly RequestDelegate         


        

Answer 1

Alternatively you can also add a middleware directly in the Startup.cs Configure method.

        app.Use(
            next =>
            {
                return async context =>
                {
                    var stopWatch = new Stopwatch();
                    stopWatch.Start();
                    context.Response.OnStarting(
                        () =>
                        {
                            stopWatch.Stop();
                            context.Response.Headers.Add("X-ResponseTime-Ms", stopWatch.ElapsedMilliseconds.ToString());
                            return Task.CompletedTask;
                        });

                    await next(context);
                };
            });

        app.UseMvc();