Startup.cs

using AttendanceProAPI.Data;
using AttendanceProAPI.Models;
using AttendanceProAPI.Services;
using AttendanceProAPI.Services.Interfaces;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.PlatformAbstractions;
using Microsoft.IdentityModel.Tokens;
using Microsoft.OpenApi.Models;
using System.Collections.Generic;
using System.IO;
using System.Security.Claims;

namespace AttendanceProAPI
{
    public class Startup
    {
        private const string CorsPolicyName = "EnableCORS";
        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.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
                .AddJwtBearer(options => 
                {
                    options.Authority = Configuration["Auth0Domain"];
                    options.Audience = Configuration["Auth0Audience"];
                    options.TokenValidationParameters = new TokenValidationParameters
                    {
                        NameClaimType = ClaimTypes.NameIdentifier
                    };
                });
            services.AddCors(options =>
            {
                options.AddPolicy(CorsPolicyName, builder =>
                {
                    builder.AllowAnyOrigin().AllowAnyHeader().AllowAnyMethod().Build();
                });
            });
            //Dependency Injection
            services.AddDbContext<DataContext>(x => x.UseNpgsql(Configuration.GetConnectionString("AttendanceProDB")));
            services.AddScoped<IAuth0Service, Auth0Service>();
            services.AddScoped<IStudentService, StudentService>();
            services.AddScoped<ICourseService, CourseService>();
            services.AddScoped<ISendGridService, SendGridService>();
            services.AddScoped<IBlobStorageService, BlobStorageService>();
            services.AddHttpClient<IAuth0Service, Auth0Service>();
            services.AddControllers();
            services.Configure<Auth0Settings>(Configuration);
            services.Configure<SendGridSettings>(Configuration);
            services.AddSwaggerGen(c =>
            {
                c.SwaggerDoc("v1", new OpenApiInfo { Title = "AttendancePro API" });
                c.AddSecurityDefinition("Bearer", new OpenApiSecurityScheme
                {
                    Description = "JWT Authorization header using the Bearer scheme for Attendance Platform. Example: \"Authorization: Bearer {token}\"",
                    Name = "Authorization",
                    In = ParameterLocation.Header,
                    Type = SecuritySchemeType.ApiKey
                });
                c.AddSecurityRequirement(new OpenApiSecurityRequirement()
                {
                    {
                        new OpenApiSecurityScheme
                        {
                            Reference = new OpenApiReference
                            {
                                Type = ReferenceType.SecurityScheme,
                                Id = "Bearer"
                            },
                            Scheme = "oauth2",
                            Name = "Bearer",
                            In = ParameterLocation.Header,

                        },
                        new List<string>()
                    }
                });
                var filePath = Path.Combine(PlatformServices.Default.Application.ApplicationBasePath, "AttendanceProAPI.xml");
                c.IncludeXmlComments(filePath);
            });
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            app.UseCors(options => options.AllowAnyOrigin().AllowAnyHeader().AllowAnyMethod());
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseSwagger();
                app.UseSwaggerUI(c => c.SwaggerEndpoint("/swagger/v1/swagger.json", "AttendanceProAPI v1"));
            }

            app.UseHttpsRedirection();

            app.UseRouting();

            app.UseAuthentication();

            app.UseAuthorization();

            app.UseCors();

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