4

我以为我会尝试使用 Blazor 服务器端，到目前为止，我已经设法以一种或另一种方式克服了大多数令人头疼的问题，并享受它，直到现在。

我正在尝试为需要用户 IP 地址的 Google Recaptcha v3 编写验证器。通常我会得到 IHttpContextAccessor ：

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

但现在返回 null！我还发现尝试以相同方式获取 IConfiguration 失败，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 地址放入验证器的任何想法？

谢谢！

编辑：

我刚刚发现使 httpContextAccessor 为空的错误！

((System.RuntimeType)validationContext.ObjectType).DeclaringMethodthrew 类型为“System.InvalidOperationException”的异常

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;

    }
}
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1 回答 1

4

对于这个问题，是由于DataAnnotationsValidator调用AddDataAnnotationsValidation时没有将 IServiceProvider 传递给ValidationContext.

对于这个问题，您可以检查Make dependency resolution available for EditContext form validation 这样自定义验证器可以访问服务。#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();
}

对于解决方法，您可以实现自己的DataAnnotationsValidator和AddDataAnnotationsValidation.

请按照以下步骤操作：

  1. 风俗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. 风俗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. 替换DataAnnotationsValidator为DIDataAnnotationsValidator

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

  4. 对于IHttpContextAccessor, 你需要在Startup.cslike中注册

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

    services.AddHttpContextAccessor();
}
于 2019-09-11T09:27:13.310 回答