How to benchmark API requests in ASP.NET Core

June 18, 2020 1-minute read

.NET

The code for this example can be found on Github

It’s helpful to see how long API requests are taking. In .NET core it’s not difficult to add a middleware that will add a response header to your response which tells you how long the request took on the server. We’ve added x-time-elapsed.

alt text

BenchmarkMiddleware.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc.Filters;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading.Tasks;

namespace BenchmarkApiRequests
{
    public class BenchmarkMiddleware
    {
        private readonly RequestDelegate next;

        public BenchmarkMiddleware(RequestDelegate next)
        {
            this.next = next;
        }

        public async Task InvokeAsync(HttpContext context)
        {
            Stopwatch stopwatch = Stopwatch.StartNew();
            context.Response.OnStarting(() =>
            {
                stopwatch.Stop();
                context.Response.Headers.Add("x-time-elapsed", stopwatch.Elapsed.ToString());
                return Task.CompletedTask;
            });
            await this.next(context);

        }
    }
    public static class BenchmarkMiddlewareExtensions
    {
        public static IApplicationBuilder UseBenchmarkMiddleware(
            this IApplicationBuilder builder)
        {
            return builder.UseMiddleware<BenchmarkMiddleware>();
        }
    }
}

Startup.cs

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
    }

    app.UseBenchmarkMiddleware();

...