Cheranga

using Demo.Products.Api;
using Demo.Products.Api.Core;
using Demo.Products.Api.Core.Filters;
using Demo.Products.Api.Extensions;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services
    .AddControllers(options => { options.Filters.Add<ApiValidationFilter>(); })

Cheranga

public static class FluentValidationExtensions
{
    public static void RegisterValidatorsInAssembly(this IMvcBuilder builder, Assembly assembly)
    {
        builder.RegisterValidatorsInAssemblyList(assembly);
    }

    public static void RegisterValidatorsInAssemblyList(this IMvcBuilder builder, params Assembly[] assemblies)
    {
        var assemblyList = assemblies?.ToList() ?? new List<Assembly>();

Cheranga

public interface ICustomValidatorFactory
{
    IValidator GetValidatorFor(Type type);
}

public class CustomValidatorFactory : ICustomValidatorFactory
{
    private readonly IServiceProvider _serviceProvider;

    public CustomValidatorFactory(IServiceProvider serviceProvider)

Cheranga

public static class ValidationResultExtensions
{   
    public static ProblemDetails ToProblemDetails(this IEnumerable<ValidationFailure> validationFailures)
    {
        var errors = validationFailures.ToDictionary(x => x.PropertyName, x => x.ErrorMessage);
        
        var problemDetails = new ProblemDetails
        {
            Type = "ValidationError",
            Detail = "invalid request, please check the error list for more details",

Cheranga

public class ApiValidationFilter : IAsyncActionFilter
{
    private readonly ICustomValidatorFactory _validatorFactory;

    public ApiValidationFilter(ICustomValidatorFactory validatorFactory)
    {
        _validatorFactory = validatorFactory;
    }
    
    public async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)

Cheranga

[HybridBindClass(new []{Source.Header, Source.Body})]
public class RequestDto
{
    [HybridBindProperty(Source.Header, name: "X-Correlation-ID")]
    public string CorrelationId { get; set; }

    public string Id { get; set; }
    public string Name { get; set; }
    public decimal Price { get; set; }
}

Cheranga

[ApiController]
public class CreateProductsController : ControllerBase
{
    private readonly ICreateProductService _service;

    public CreateProductsController(ICreateProductService service)
    {
        _service = service;
    }

Cheranga

public class AddProductRequestDtoValidator : ModelValidatorBase<AddProductRequestDto>
{
    public AddProductRequestDtoValidator()
    {
        RuleFor(x => x.Id).NotNull().NotEmpty().WithMessage("id is required");
        RuleFor(x => x.Name).MustAsync(async (s, token) =>
        {
            // simulating an asynchronous call
            await Task.Delay(TimeSpan.FromSeconds(1), token);
            return !string.IsNullOrWhiteSpace(s);

Cheranga

using Demo.Products.Api;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.

builder.Services.AddControllers().AddHybridModelBinder();
Bootstrapper.RegisterDependencies(builder);
...
...

Cheranga

public static class Bootstrapper
{
    public static void RegisterDependencies(WebApplicationBuilder builder)
    {
        // register fluent validation as part of the ASP.NET pipeline
        builder.Services.AddValidatorsFromAssembly(typeof(Program).Assembly)
            .AddFluentValidationAutoValidation();
        
        builder.Services.AddSingleton<ICreateProductService, CreateProductService>();
    }