Angular / ASP.NET Core 2.1 CORS issue

Question

The situation is that I had an existing angular application and I am changing the the backend service to ASP.NET Core 2.1. I have successfully create the API and I have enabled CORS in my service registration in the startup.cs file but when I try to access any specific url of my api it this error message

Access to XMLHttpRequest at ' https://localhost:44329/api/ThinkTank/Index ' from origin ' http://localhost:4200 ' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource

I think it is a problem with my startup page so I put it below

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;

namespace CPDEPCoreApi
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        readonly string MyAllowSpecificOrigins = "https://localhost:44329";
        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.AddCors(options =>
            {
                options.AddPolicy(MyAllowSpecificOrigins,
                builder =>
                {
                    builder.WithOrigins("https://localhost:44329")
                    .AllowAnyHeader()
                    .AllowAnyMethod(); ;
                });
            });
            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;
            });


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

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

Thanks in advance for your help.

Answer 1

Your origin is localhost:4200 not localhost:44329 (that's your server).

Change this line builder.WithOrigins("https://localhost:44329") to builder.WithOrigins("http://localhost:4200")