validation

AppHost.cs

public class AppHost : AppHostBase
{
    public AppHost() : base("Web",typeof(MyServices).Assembly){}

    public override void Configure(Container container)
    {
        Plugins.Add(new ValidationFeature());

        // Register custom validator
        container.Register<IAddressValidator>(
            new AddressValidator());
    }
}

MyServices.cs

public class MyServices : Service
{
    public object Post(CreateUser request)
    {
        var id = Db.Insert(request.ConvertTo<User>());
        var user = Db.SingleById<User>(id);
        return user;
    }
}

Users.cs

[Route("/users", "POST")]
public class CreateUser : IReturn<User>
{
    public string Name { get; set; }
    public string Company { get; set; }
    public int Age { get; set; }
    public int Count { get; set; }
    public string Address { get; set; }
}

public class User
{
    [AutoIncrement]
    public int Id { get; set; }
    public string Name { get; set; }
    public string Company { get; set; }
    public int Age { get; set; }
    public int Count { get; set; }
    public string Address { get; set; }
}

Validation.cs

public interface IAddressValidator
{
    bool ValidAddress(string address);
}

public class AddressValidator : IAddressValidator
{
    public bool ValidAddress(string address)
    {
        return address != null
           && address.Length >= 20
           && address.Length <= 250;
    }
}

public class UserValidator : AbstractValidator<CreateUser>
{
    // Resolved from IoC
    public IAddressValidator AddressValidator { get; set; }

    public UserValidator()
    {
        //Validation rules for all requests
        RuleFor(r => r.Name).NotEmpty();
        RuleFor(r => r.Age).GreaterThan(0);
        RuleFor(x => x.Address).Must(x => 
            AddressValidator.ValidAddress(x));
    }
}