我一直在努力解决一个问题。我正在基于eShopOnContainers GitHub项目See Here构建一个项目。我的项目在asp.net core 2.2上运行,我正在使用
MediatR 6.0,
我正在使用由命令处理程序处理的MediatR命令,并且通过许多文章以及在线eShopOnContainers示例,我实现了一个ValidatorBehavior
类,该类实现了IPipelineBehavior
。
public class ValidatorBehavior<TRequest, TResponse> : IPipelineBehavior<TRequest, TResponse>
where TRequest : IRequest<TResponse>
{
private readonly IEnumerable<IValidator<TRequest>> _validators;
public ValidatorBehavior(IEnumerable<IValidator<TRequest>> validators)
{
_validators = validators;
}
public async Task<TResponse> Handle(TRequest request, CancellationToken cancellationToken, RequestHandlerDelegate<TResponse> next)
{
var context = new ValidationContext(request);
var failures = _validators
.Select(v => v.Validate(context))
.SelectMany(result => result.Errors)
.Where(error => error != null)
.ToList();
if (failures.Any())
{
throw new PlanningDomainException(
$"Command Validation Errors for type {typeof(TRequest).Name}", new ValidationException("Validation exception", failures));
}
var response = await next();
return response;
}
}
我还包括一个MediatorModule,与示例项目中实现的一样。
public class MediatorModule : Autofac.Module
{
protected override void Load(ContainerBuilder builder)
{
builder.RegisterAssemblyTypes(typeof(IMediator).GetType().Assembly)
.AsImplementedInterfaces();
// Get the assembly name
var assembly = typeof(Startup).GetType().Assembly;
// Register all the Command classes (they implement IRequestHandler) in assembly holding the Commands
builder.RegisterAssemblyTypes(assembly)
.AsClosedTypesOf(typeof(IRequestHandler<,>));
// Register the DomainEventHandler classes (they implement INotificationHandler<>)
// in assembly holding the Domain Events
builder.RegisterAssemblyTypes(assembly)
.AsClosedTypesOf(typeof(INotificationHandler<>));
// Register the Command's Validators (Validators based on FluentValidation library)
builder.RegisterAssemblyTypes(assembly)
.Where(t => t.IsClosedTypeOf(typeof(IValidator<>)))
.AsImplementedInterfaces();
builder.Register<ServiceFactory>(context =>
{
var componentContext = context.Resolve<IComponentContext>();
return t => { object o; return componentContext.TryResolve(t, out o) ? o : null; };
});
builder.RegisterGeneric(typeof(LoggingBehavior<,>)).As(typeof(IPipelineBehavior<,>));
builder.RegisterGeneric(typeof(ValidatorBehavior<,>)).As(typeof(IPipelineBehavior<,>));
builder.RegisterGeneric(typeof(TransactionBehaviour<,>)).As(typeof(IPipelineBehavior<,>));
}
}
我的测试控制器是:
[Route("api/[controller]")]
[ApiController]
public class ApplicationsController : ControllerBase
{
private readonly IMediator _mediator;
public ApplicationsController(IMediator mediator)
{
_mediator = mediator ?? throw new ArgumentNullException(nameof(mediator));
}
[HttpPost]
[ProducesResponseType((int)HttpStatusCode.OK)]
[ProducesResponseType((int)HttpStatusCode.BadRequest)]
public async Task<IActionResult> Put([FromBody]ApplicationCreateCommand command, [FromHeader(Name = "x-requestid")] string requestId)
{
var c = await _mediator.Send(command);
return c ? Ok() : (IActionResult)BadRequest();
}
}
我遇到以下问题:
每当我尝试调用此API时,都会出现以下错误:
无法解析构造函数'Void .ctor(MediatR.IMediator)'的参数'MediatR.IMediator中介器。”
我正在通过使用.AddMediatR()
将中介程序作为服务添加来解决此问题,即使在示例项目中也从未那样添加。
ValidatorBehavior
被正确调用,但CommandValidator不存在。 _validators
列表实际上是空的,因此没有进行验证。我还在命令验证器中设置了断点,但是没有命中任何点。
这是我的命令验证器:
public class ApplicationCreateCommandValidator : AbstractValidator<ApplicationCreateCommand>
{
public ApplicationCreateCommandValidator()
{
RuleFor(cmd => cmd.CategoryType).NotEmpty().Must(BeValidCategoryType).WithMessage("The category type is not valid.");
RuleFor(cmd => cmd.CompetitionId).NotEmpty().WithMessage("The competition id must be specified.");
RuleFor(cmd => cmd.ParticipantId).NotEmpty().WithMessage("The participant id must be specified.");
}
private bool BeValidCategoryType(int categoryType)
{
return categoryType != 0;
}
}
一切正常!我不明白为什么不会。也许我没有在autofac中正确加载命令验证器,但是,我在网上找到的每个示例代码都指向相同的注册方法:
builder.RegisterAssemblyTypes(assembly)
.Where(t => t.IsClosedTypeOf(typeof(IValidator<>)))
.AsImplementedInterfaces();
如果您想仔细看看,我在git hub帐户中拥有该项目的全部源代码。 This is the API。
有人可以帮助我了解我在做什么错吗?这几天让我发疯。
答案 0 :(得分:1)
我的配置与您相似。我唯一能找到的区别是在start.cs文件中的行下方
public IServiceProvider ConfigureServices(IServiceCollection services)
{
services.AddMvc()
.AddFluentValidation(fv =>
{
fv.RegisterValidatorsFromAssemblyContaining<MediatorModule>();
fv.RunDefaultMvcValidationAfterFluentValidationExecutes = false;
}
);
}