Persilsoft.ValidationService.FluentValidation 1.0.4

An implementation of Persilsoft.Validation using FluentValidation.

Example

Let's start by creating a class to register an order with its details.

public class CreateOrderDto(string customerId, string shipAddress, string shipPostalCode, IEnumerable<CreateOrderDetailDto> orderDetails)
{
    public string CustomerId => customerId;
    public string ShipAddress => shipAddress;
    public string ShipPostalCode => shipPostalCode;
    public IEnumerable<CreateOrderDetailDto> OrderDetails => orderDetails;
}

public class CreateOrderDetailDto(int productId, decimal unitPrice, short quantity)
{
    public int ProductId => productId;
    public decimal UnitPrice => unitPrice;
    public short Quantity => quantity;
}

Now, let's implement validators for each model.

using Persilsoft.Validation.Abstracts;
using Persilsoft.Validation.Interfaces;

public class CreateOrderDtoValidator : AbstractModelValidator<CreateOrderDto>
{
    public CreateOrderDtoValidator(IValidationService<CreateOrderDto> validationService,
        IModelValidator<CreateOrderDetailDto> detailValidator)
        : base(validationService)
    {
        AddRuleFor(dto => dto.CustomerId)
            .NotEmpty("Customer Id is required.")
            .Length(7, "Customer Id must have 7 characters.");

        AddRuleFor(dto => dto.ShipAddress)
            .NotEmpty("Ship address is required.")
            .MinimumLength(20, "Ship address must have a minimum lenght of 20 characters.")
            .MaximumLength(50, "Ship address must have a maximum lenght of 50 characters.");

        AddRuleFor(dto => dto.ShipPostalCode)
            .NotEmpty("Ship postal code is required")
            .Length(5, "Ship postal code must have 5 characters.");

        AddRuleFor(dto => dto.OrderDetails)
            .NotNull("Order details is required.")
            .NotNull("Order details must not be empty");

        AddRuleForEach(dto => dto.OrderDetails)
            .SetValidator(detailValidator);
    }
}

using Persilsoft.Validation.Abstracts;
using Persilsoft.Validation.Interfaces;

internal class CreateOrderDetailDtoValidator :
    AbstractModelValidator<CreateOrderDetailDto>
{
    public CreateOrderDetailDtoValidator(IValidationService<CreateOrderDetailDto> validationService)
        : base(validationService)
    {
        AddRuleFor(d => d.ProductId)
            .GreaterThan(0, "Product Id must be greater than 0.");

        AddRuleFor<int>(d => d.Quantity)
            .GreaterThan(0, "Quantity must be greater than 0.");

        AddRuleFor(d => d.UnitPrice)
            .GreaterThan<decimal>(0, "Unit price must be greater than 0.");
    }
}

Next, let's register the validators and the validation service.

using ServiceCollectionExtensions;

builder.Services.AddModelValidator<CreateOrderDto, CreateOrderDtoValidator>();
builder.Services.AddModelValidator<CreateOrderDetailDto, CreateOrderDetailDtoValidator>();
builder.Services.AddValidationService();

Now, let's implement an Endpoint that receives the model, and we'll inject the validation hub for the model.

using Persilsoft.Exceptions.CustomExceptions;
using Persilsoft.Validation.Interfaces;

app.MapPost("/order/register", async (CreateOrderDto order, IModelValidatorHub<CreateOrderDto> modelValidatorHub) =>
{
    if (!await modelValidatorHub.Validate(order))
        throw new ValidationException(modelValidatorHub.Errors);

    Console.WriteLine("Sending the new order to the Database");
    await Task.Delay(750);

    return Results.Ok("Order registered!");
})
.WithName("Order");

Note:
You can use constructor injection.

You can implement a custom exception handler to handle the ValidationException and format the output appropriately, or you can include the Persilsoft.Exceptions package, which already includes a ready-to-use handler.

using ServiceCollectionExtensions;

builder.Services.AddValidationExceptionHandler();

If you will use the Persilsoft.Exceptions handler, it will be necessary to configure the Localization middleware in your AspNet Core application.

builder.Services.Configure<RequestLocalizationOptions>(options =>
{
    var SupportedCultures = new[] { "en-US", "es-PE" };
    var NeutralCulture = SupportedCultures[1];

    options.SetDefaultCulture(NeutralCulture)
    .AddSupportedCultures(SupportedCultures)6
    .AddSupportedUICultures(SupportedCultures);
});

Finally, we add the localization and exception handling middlewares to the AspNet Core pipeline

app.UseRequestLocalization();
app.UseExceptionHandler(e => { });

Note:
It's important that the localization middleware is added before the exception handling middleware; otherwise, you won't see the messages in the appropriate language.