.NET Core WebApi FluentValidation验证数据 ASP.NET Core WebApi中使用FluentValidation验证数据模型的方法（.net是干嘛的）

PM> Install-Package FluentValidation.AspNetCore

public void ConfigureServices(IServiceCollection services) 
{ 
  // mvc + validating
  services.AddMvc()
  .SetCompatibilityVersion(CompatibilityVersion.Version_2_1)
  .AddFluentValidation();
}

public class User
{
  public string Gender { get; set; }
  public string FirstName { get; set; }
  public string LastName { get; set; }
  public string SIN { get; set; }
}

public class UserValidator : AbstractValidator<User>
{
  public UserValidator()
  {
   // 在这里添加规则
  }
}

public static class Utilities
{
  public static bool IsValidSIN(int sin)
  {
   if (sin < 0 || sin > 999999998) return false;

   int checksum = 0;
   for (int i = 4; i != 0; i--)
   {
     checksum += sin % 10;
     sin /= 10;

     int addend = 2 * (sin % 10); 
     
     if (addend >= 10) addend -= 9;
     
     checksum += addend;
     sin /= 10;
   }
     
   return (checksum + sin) % 10 == 0;
  }
}

public class UserValidator : AbstractValidator<User>
{
  public UserValidator()
  {
   RuleFor(x => x.FirstName)
   .NotEmpty()
   .WithMessage("FirstName is mandatory.");

   RuleFor(x => x.LastName)
   .NotEmpty()
   .WithMessage("LastName is mandatory.");

   RuleFor(x => x.SIN)
   .NotEmpty()
   .WithMessage("SIN is mandatory.")
   .Must((o, list, context) =>
   {
     if (null != o.SIN)
     {
      context.MessageFormatter.AppendArgument("SIN", o.SIN);
      return Utilities.IsValidSIN(int.Parse(o.SIN));
     }
     return true;
   })
   .WithMessage("SIN ({SIN}) is not valid.");
  } 
}

public void ConfigureServices(IServiceCollection services) 
{ 
  // 添加验证器
  services.AddSingleton<IValidator<User>, UserValidator>();
  // mvc + validating
  services
    .AddMvc()
    .SetCompatibilityVersion(CompatibilityVersion.Version_2_1)
    .AddFluentValidation();
}

public void ConfigureServices(IServiceCollection services) 
{ 
  // Validators
  services.AddSingleton<IValidator<User>, UserValidator>();
  // mvc + validating
  services
    .AddMvc()
    .SetCompatibilityVersion(CompatibilityVersion.Version_2_1)
    .AddFluentValidation();

  // override modelstate
  services.Configure<ApiBehaviorOptions>(options =>
  {
    options.InvalidModelStateResponseFactory = (context) =>
    {
     var errors = context.ModelState
       .Values
       .SelectMany(x => x.Errors
             .Select(p => p.ErrorMessage))
       .ToList();
      
     var result = new
     {
       Code = "00009",
       Message = "Validation errors",
       Errors = errors
     };
      
     return new BadRequestObjectResult(result);
    };
  });
}

[Route("api/[controller]")]
[ApiController]
public class DemoValidationController : ControllerBase
{
  [HttpPost]
  public IActionResult Post(User user)
  {
   return NoContent();
  }
}