Startup.cs

// © Microsoft Corporation. All rights reserved.

using System;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.SpaServices.ReactDevelopmentServer;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

namespace Calling
{
    public class Startup
    {
        private const string AllowAnyOrigin = nameof(AllowAnyOrigin);

        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        public IServiceProvider ConfigureServices(IServiceCollection services)
        {
            // Allow CORS as our client may be hosted on a different domain.
            services.AddCors(options =>
            {
                options.AddPolicy(AllowAnyOrigin,
                    builder =>
                    {
                        builder.AllowAnyOrigin().AllowCredentials().AllowAnyMethod().AllowAnyHeader();
                    });
            });

            services.AddMvc(options => options.EnableEndpointRouting = false);

            // In production, the React files will be served from this directory
            services.AddSpaStaticFiles(configuration =>
            {
                configuration.RootPath = "ClientApp/build";
            });

            return services.BuildServiceProvider();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            app.UseStaticFiles();
            app.UseSpaStaticFiles();

            app.UseCors(AllowAnyOrigin);
            app.UseMvc();

            app.UseSpa(spa =>
            {
                spa.Options.SourcePath = "ClientApp";

                if (env.IsDevelopment())
                {
                    spa.Options.StartupTimeout = TimeSpan.FromSeconds(120);
                    spa.UseReactDevelopmentServer(npmScript: "start --max_old_space_size=4096");
                }
            });
        }
    }
}