Startup.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using System.Net;
using System.Net.Http;

namespace VariableGroupUsage
{
    public class Startup
    {
        public Startup(IConfiguration configuration, IHostingEnvironment env)
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(env.ContentRootPath)
                //.AddEnvironmentVariables()
                .AddConfiguration(configuration)
                .AddJsonFile(@"Properties\appsettings.json", optional: false, reloadOnChange: true);

            Configuration = builder.Build();
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.Configure<CookiePolicyOptions>(options =>
            {
                // This lambda determines whether user consent for non-essential cookies is needed for a given request.
                options.CheckConsentNeeded = context => true;
                options.MinimumSameSitePolicy = SameSiteMode.None;
            });

            if (Configuration.GetValue<string>("Connection:ProxyServer").Length > 0)
            {
                services.AddHttpClient("DevOpsClient", c =>
                {
                    c.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));
                    c.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic",
                        Convert.ToBase64String(System.Text.ASCIIEncoding.ASCII.GetBytes(string.Format("{0}:{1}", "", Configuration.GetValue<string>("AzureDevOps:PersonalAccessToken")))));
                }).ConfigurePrimaryHttpMessageHandler(() => new HttpClientHandler
                {
                    DefaultProxyCredentials = CredentialCache.DefaultCredentials,
                    Proxy = new WebProxy(new Uri(Configuration.GetValue<string>("Connection:ProxyServer")), BypassOnLocal: false),
                    UseProxy = true,
                });
            }
            else
            {
                services.AddHttpClient("DevOpsClient", c =>
                {
                    c.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));
                    c.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic",
                        Convert.ToBase64String(System.Text.ASCIIEncoding.ASCII.GetBytes(string.Format("{0}:{1}", "", Configuration.GetValue<string>("AzureDevOps:PersonalAccessToken")))));
                });
            }
            services.AddSingleton<IConfiguration>(Configuration);

            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
                app.UseHsts();
            }

            app.UseHttpsRedirection();
            app.UseStaticFiles();
            app.UseCookiePolicy();

            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller=Home}/{action=Index}/{id?}");
            });
        }
    }
}