ShowAllServicesMiddleware.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Options;
using System.Text;
using System.Threading.Tasks;

namespace WebApp
{
    public class ShowAllServicesMiddleware
    {
        private readonly ShowAllServicesConfig _config;
        private readonly RequestDelegate _next;

        public ShowAllServicesMiddleware(RequestDelegate next,
            IOptions<ShowAllServicesConfig> config)
        {
            _config = config.Value;
            _next = next;
        }

        public async Task Invoke(HttpContext httpContext)
        {
            if (httpContext.Request.Path.Equals(_config.Path))
            {
                var sb = new StringBuilder();
                sb.Append("<h1>All Services</h1>");
                sb.Append("<table><thead>");
                sb.Append("<tr><th>Type</th><th>Lifetime</th><th>Instance</th></tr>");
                sb.Append("</thead><tbody>");

                foreach (var serviceDescriptor in httpContext.RequestServices.GetService<IServiceCollection>())
                {
                    sb.Append("<tr>");
                    sb.Append($"<td>{serviceDescriptor.ServiceType.Name}</td>");
                    sb.Append($"<td>{serviceDescriptor.Lifetime}</td>");
                    sb.Append($"<td>{serviceDescriptor.ImplementationType?.Name}</td>");
                    sb.Append("</tr>");
                }
                sb.Append("</tbody></table>");

                await httpContext.Response.WriteAsync(sb.ToString());
            }
            else
            {
                await _next(httpContext);
            }
        }
    }

    // Extension method used to add the middleware to the HTTP request pipeline.
    public static class ShowAllServicesMiddlewareExtensions
    {
        public static IApplicationBuilder UseShowAllServicesMiddleware(this IApplicationBuilder builder)
        {
            return builder.UseMiddleware<ShowAllServicesMiddleware>();
        }
    }

    public class ShowAllServicesConfig
    {
        public string Path { get; set; } = "/appservices";
    }
}