The SignInScheme for a remote authentication handler cannot be set to itself

Question

I'm trying to add a Google Jwt Validation in .NetCore WebApi

I have a standalone frontend that is already logging in to Google and generating a Jwt. I want to pass this Jwt into the backend with each service call to ensure that the user is authenticated. (anyone with a google account is authenticated)

Here's what I have so far.

My frontend makes a request with the following header
Authorization: Bearer <Token>

My controller has a simple [Authorize] attribute

        [HttpGet]
        [Authorize]
        public IEnumerable<WeatherForecast> Get()
        {
            var rng = new Random();
            return Enumerable.Range(1, 5).Select(index => new WeatherForecast
            {
                Date = DateTime.Now.AddDays(index),
                TemperatureC = rng.Next(-20, 55),
                Summary = Summaries[rng.Next(Summaries.Length)]
            })
            .ToArray();
        }

And my startup.cs looks like

using System.Text;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.AspNetCore.Authentication.Google;
using Microsoft.IdentityModel.Tokens;
using Microsoft.AspNetCore.Identity;

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

        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.AddControllers();
            services.AddAuthentication(options =>
            {
                options.DefaultScheme = GoogleDefaults.AuthenticationScheme;
                options.DefaultChallengeScheme = "None";
            })
            .AddGoogle(options =>
                {
                    options.ClientId = "redacted";
                    options.ClientSecret = "redacted";
                });
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseRouting();

            app.UseAuthentication();
            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }
    }
}

Lazar Đorđević · Answer 1 · 2020-07-08T16:31:15.030

Useful line of when you working with JWT :

int userId = int.Parse(User.FindFirst(ClaimTypes.NameIdentifier).Value);

I used this or similar piece of when I need to check if request is from registered user, or ID of user.

In startup.cs:

services.AddAuthentication(options =>
            {
                options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
                options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
            })
                   .AddJwtBearer(options =>
                   {
                       options.TokenValidationParameters = new TokenValidationParameters
                       {
                           ValidateIssuerSigningKey = true,
                           IssuerSigningKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes(Configuration.GetSection("AppSettings:Secret").Value)),
                           ValidateIssuer = false,
                           ValidateAudience = false
                       };
                       options.Events = new JwtBearerEvents
                       {
                           OnMessageReceived = context =>
                           {
                               var accessToken = context.Request.Query["access_token"];

                               // If the request is for our hub...
                               var path = context.HttpContext.Request.Path;
                               if (!string.IsNullOrEmpty(accessToken) &&
                                   (path.StartsWithSegments("/chat")))
                               {
                                   // Read the token out of the query string
                                   context.Token = accessToken;
                               }
                               return Task.CompletedTask;
                           }
                       };
                   });

I used SignalR to implement messaging system so maybe you don't need every line of code, but this is how I used JWT on back-end for my project.

About google-authentication you could check this post: google Jwt authentication and Microsoft documentation

I was able to use khellang's package listed in this post https://stackoverflow.com/questions/48727900/google-jwt-authentication-with-aspnet-core-2-0 — moondc, Jul 08 '20 at 17:02

The SignInScheme for a remote authentication handler cannot be set to itself

1 Answers1