asp.net-core - Blazor recaptcha 验证属性 IHttpContextAccessor 始终为 null

Question

我想尝试一下使用 Blazor 服务器端，到目前为止，我已经设法以某种方式克服了大多数令人头疼的问题，并且很享受它，直到现在。

我正在尝试为 Google Recaptcha v3 编写一个验证器，它需要用户的 IP 地址。通常我会通过以下方式获取 IHttpContextAccessor:

var httpContextAccessor = (IHttpContextAccessor)validationContext.GetService(typeof(IHttpContextAccessor));

但是现在返回 null!我还发现尝试以相同的方式获取 IConfiguration 失败了，但为此，我可以在 Startup.cs 中创建一个静态属性。

这是一天工作中的最后一个障碍，这让我感到困惑。

关于如何将该 IP 地址输入验证器有什么想法吗？

谢谢!

编辑:

我刚刚发现 httpContextAccessor 为空的错误!

((System.RuntimeType)validationContext.ObjectType).DeclaringMethodthrew an exception of type 'System.InvalidOperationException'

这是验证器:

public class GoogleReCaptchaValidationAttribute : ValidationAttribute
    {

    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        Lazy<ValidationResult> errorResult = new Lazy<ValidationResult>(() => new ValidationResult("Google reCAPTCHA validation failed", new String[] { validationContext.MemberName }));

        if (value == null || String.IsNullOrWhiteSpace(value.ToString()))
        {
            return errorResult.Value;
        }

        var configuration = Startup.Configuration;
        string reCaptchResponse = value.ToString();
        string reCaptchaSecret = configuration["GoogleReCaptcha:SecretKey"];
        IHttpContextAccessor httpContextAccessor = validationContext.GetService(typeof(IHttpContextAccessor)) as IHttpContextAccessor;
        var content = new FormUrlEncodedContent(new[]
        {
            new KeyValuePair<string, string>("secret", reCaptchaSecret),
            new KeyValuePair<string, string>("response", reCaptchResponse),
            new KeyValuePair<string, string>("remoteip", httpContextAccessor.HttpContext.Connection.RemoteIpAddress.ToString())
        });

        HttpClient httpClient = new HttpClient();
        var httpResponse = httpClient.PostAsync("https://www.google.com/recaptcha/api/siteverify", content).Result;
        if (httpResponse.StatusCode != HttpStatusCode.OK)
        {
            return errorResult.Value;
        }

        String jsonResponse = httpResponse.Content.ReadAsStringAsync().Result;
        dynamic jsonData = JObject.Parse(jsonResponse);
        if (jsonData.success != true.ToString().ToLower())
        {
            return errorResult.Value;
        }

        return ValidationResult.Success;

    }
}

Answer 1

这个问题是由于DataAnnotationsValidator 时引起的调用AddDataAnnotationsValidation ，它没有将 IServiceProvider 传递给 ValidationContext。

对于这个问题，您可以查看Make dependency resolution available for EditContext form validation so that custom validators can access services. #11397

private static void ValidateModel(EditContext editContext, ValidationMessageStore messages)
{
    var validationContext = new ValidationContext(editContext.Model);
    var validationResults = new List<ValidationResult>();
    Validator.TryValidateObject(editContext.Model, validationContext, validationResults, true);

    // Transfer results to the ValidationMessageStore
    messages.Clear();
    foreach (var validationResult in validationResults)
    {
        foreach (var memberName in validationResult.MemberNames)
        {
            messages.Add(editContext.Field(memberName), validationResult.ErrorMessage);
        }
    }

    editContext.NotifyValidationStateChanged();
}

要解决此问题，您可以实现自己的 DataAnnotationsValidator 和 AddDataAnnotationsValidation 。

按照以下步骤操作:

1. 自定义DataAnnotationsValidator

   public class DIDataAnnotationsValidator: DataAnnotationsValidator
   {
       [CascadingParameter] EditContext DICurrentEditContext { get; set; }
   
       [Inject]
       protected IServiceProvider ServiceProvider { get; set; }
       protected override void OnInitialized()
       {
           if (DICurrentEditContext == null)
           {
               throw new InvalidOperationException($"{nameof(DataAnnotationsValidator)} requires a cascading " +
                   $"parameter of type {nameof(EditContext)}. For example, you can use {nameof(DataAnnotationsValidator)} " +
                   $"inside an EditForm.");
           }
   
           DICurrentEditContext.AddDataAnnotationsValidationWithDI(ServiceProvider);
       }
   }
   

2. 自定义EditContextDataAnnotationsExtensions

   public static class EditContextDataAnnotationsExtensions
   {
       private static ConcurrentDictionary<(Type ModelType, string FieldName), PropertyInfo> _propertyInfoCache
       = new ConcurrentDictionary<(Type, string), PropertyInfo>();
   
       public static EditContext AddDataAnnotationsValidationWithDI(this EditContext editContext, IServiceProvider serviceProvider)
       {
           if (editContext == null)
           {
               throw new ArgumentNullException(nameof(editContext));
           }
   
           var messages = new ValidationMessageStore(editContext);
   
           // Perform object-level validation on request
           editContext.OnValidationRequested +=
               (sender, eventArgs) => ValidateModel((EditContext)sender, serviceProvider, messages);
   
           // Perform per-field validation on each field edit
           editContext.OnFieldChanged +=
               (sender, eventArgs) => ValidateField(editContext, serviceProvider, messages, eventArgs.FieldIdentifier);
   
           return editContext;
       }
       private static void ValidateModel(EditContext editContext, IServiceProvider serviceProvider,ValidationMessageStore messages)
       {
           var validationContext = new ValidationContext(editContext.Model, serviceProvider, null);
           var validationResults = new List<ValidationResult>();
           Validator.TryValidateObject(editContext.Model, validationContext, validationResults, true);
   
           // Transfer results to the ValidationMessageStore
           messages.Clear();
           foreach (var validationResult in validationResults)
           {
               foreach (var memberName in validationResult.MemberNames)
               {
                   messages.Add(editContext.Field(memberName), validationResult.ErrorMessage);
               }
           }
   
           editContext.NotifyValidationStateChanged();
       }
   
       private static void ValidateField(EditContext editContext, IServiceProvider serviceProvider, ValidationMessageStore messages, in FieldIdentifier fieldIdentifier)
       {
           if (TryGetValidatableProperty(fieldIdentifier, out var propertyInfo))
           {
               var propertyValue = propertyInfo.GetValue(fieldIdentifier.Model);
               var validationContext = new ValidationContext(fieldIdentifier.Model, serviceProvider, null)
               {
                   MemberName = propertyInfo.Name
               };
               var results = new List<ValidationResult>();
   
               Validator.TryValidateProperty(propertyValue, validationContext, results);
               messages.Clear(fieldIdentifier);
               messages.Add(fieldIdentifier, results.Select(result => result.ErrorMessage));
   
               // We have to notify even if there were no messages before and are still no messages now,
               // because the "state" that changed might be the completion of some async validation task
               editContext.NotifyValidationStateChanged();
           }
       }
   
       private static bool TryGetValidatableProperty(in FieldIdentifier fieldIdentifier, out PropertyInfo propertyInfo)
       {
           var cacheKey = (ModelType: fieldIdentifier.Model.GetType(), fieldIdentifier.FieldName);
           if (!_propertyInfoCache.TryGetValue(cacheKey, out propertyInfo))
           {
               // DataAnnotations only validates public properties, so that's all we'll look for
               // If we can't find it, cache 'null' so we don't have to try again next time
               propertyInfo = cacheKey.ModelType.GetProperty(cacheKey.FieldName);
   
               // No need to lock, because it doesn't matter if we write the same value twice
               _propertyInfoCache[cacheKey] = propertyInfo;
           }
   
           return propertyInfo != null;
       }
   
   }
   

3. 将 DataAnnotationsValidator 替换为 DIDataAnnotationsValidator

   <EditForm Model="@starship" OnValidSubmit="@HandleValidSubmit">
       @*<DataAnnotationsValidator />*@
       <DIDataAnnotationsValidator />
       <ValidationSummary />    
   </EditForm>
   

4. 对于IHttpContextAccessor，您需要在Startup.cs中注册，例如

   public void ConfigureServices(IServiceCollection services)
   {
       services.AddRazorPages();
       services.AddServerSideBlazor();
   
       services.AddHttpContextAccessor();
   }