Startup.cs

using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Microsoft.IdentityModel.Tokens;
using Microsoft.OpenApi.Models;
using CityGuideApi.Data;
using CityGuideApi.Helpers;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.Json.Serialization;
using System.Threading.Tasks;

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

        public IConfiguration Configuration { get; }

        public void ConfigureServices(IServiceCollection services)
        {
            var key = Encoding.ASCII.GetBytes(Configuration.GetSection("AppSettings:Token").Value);
            services.Configure<CloudinarySettings>(Configuration.GetSection("CouldinarSettings"));
            services.AddControllers();
            services.AddControllersWithViews()
                    .AddNewtonsoftJson(options =>options.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore);
            services.AddDbContext<DataContext>(x => x.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
            services.AddAutoMapper(typeof(Startup));

            services.AddMvc().AddJsonOptions(o =>
            {
                o.JsonSerializerOptions.ReferenceHandler = ReferenceHandler.Preserve;
            });
            services.AddSwaggerGen(c =>
            {
                c.SwaggerDoc("v1", new OpenApiInfo { Title = "CityGuideApi", Version = "v1" });
            });
            services.AddCors();

            services.AddScoped<IAppRepository, AppRepository>();
            services.AddScoped<IAuthRepository, AuthRepository>();
            services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme).AddJwtBearer(options => {
                options.TokenValidationParameters = new Microsoft.IdentityModel.Tokens.TokenValidationParameters
                {
                    ValidateIssuerSigningKey=true,
                    IssuerSigningKey=new SymmetricSecurityKey(key),
                    ValidateIssuer=false,
                    ValidateAudience=false

                };
            
            
            });
                
        }

        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseSwagger();
                app.UseSwaggerUI(c => c.SwaggerEndpoint("/swagger/v1/swagger.json", "CityGuideApi v1"));
            }

            app.UseCors(x => x
            .AllowAnyOrigin()
            .AllowAnyMethod()
            .AllowAnyHeader());
            app.UseHttpsRedirection();

            app.UseRouting();

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

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