Program.cs

using System.Text;
using System.Text.Json.Serialization;
using Blog;
using Blog.Data;
using Blog.Services;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.IdentityModel.Tokens;

var builder = WebApplication.CreateBuilder(args);
ConfigureAuthentication(builder);
ConfigureMvc(builder);
ConfigureServices(builder);

builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

var app = builder.Build();

LoadConfiguration(app);

app.UseAuthentication();
app.UseAuthorization();
app.UseStaticFiles();
app.MapControllers();

if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.Run();


void LoadConfiguration (WebApplication app)
{
    Configuration.JwtKey = app.Configuration.GetValue<string>("JwtKey");
    Configuration.ApiKeyName = app.Configuration.GetValue<string>("ApiKeyName");
    Configuration.ApiKey = app.Configuration.GetValue<string>("ApiKey");

    var smtp = new Configuration.SmtpConfiguration(); //instanciando a classe Smtp configuration 
    app.Configuration.GetSection("Smtp").Bind(smtp);
    Configuration.Smtp = smtp;

}

void ConfigureAuthentication(WebApplicationBuilder builder)
{
    var key = Encoding.ASCII.GetBytes(Configuration.JwtKey);
    builder.Services.AddAuthentication(options =>
    {
        options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
        options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
    }).AddJwtBearer(options =>
    {
        options.TokenValidationParameters = new TokenValidationParameters
        {
            ValidateIssuerSigningKey = true,
            IssuerSigningKey = new SymmetricSecurityKey(key),
            ValidateIssuer = false,
            ValidateAudience = false
        };
    });

}


void ConfigureMvc(WebApplicationBuilder builder)
{
    builder
        .Services
        .AddControllers()
        .ConfigureApiBehaviorOptions(options =>
        {
            options.SuppressModelStateInvalidFilter = true;
        })
        .AddJsonOptions(x =>
        {
            x.JsonSerializerOptions.ReferenceHandler = ReferenceHandler.IgnoreCycles;
            x.JsonSerializerOptions.DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingDefault; //objetos como null não irão renderizar 
        });
  
}

void ConfigureServices(WebApplicationBuilder builder)
{
    builder.Services.AddDbContext<BlogDataContext>();
    builder.Services.AddTransient<TokenServices>(); //sempre cria uma nova instância um novo Token
    builder.Services.AddTransient<EmailService>();
}