Question

我知道您可以在模型上使用验证属性来验证它：

public class CommunicationQuery
{
    [RegularExpression("[0-9]{0,10}", ErrorMessage = "Please enter a valid policy number")]
    public string PolicyId { get; set; }
    [RegularExpression("[0-9]{0,10}", ErrorMessage = "Please enter a valid member number")]
    public string MemberId { get; set; }
}

public IEnumerable<Communication> Get([FromUri]CommunicationQuery documentQuery)
{

}

但是可以使用验证属性验证单个字符串吗？

public async Task<HttpResponseMessage> Get([RegularExpression("[0-9]{0,10}")]string id)
{

}

这似乎不起作用。我能够做到这一点的唯一方法是创建包装器对象并使用[FromUri]，在操作本身上使用自定义ActionFilterAttribute或手动验证控制器操作中的参数使用正则表达式。

Answer 1

其他两个解决方案仅适用于路由属性。但是，如果您想验证查询参数，可以执行以下操作：

public class MinWithStatusAttribute : ParameterBindingAttribute 
{
    private readonly int _minValue;
    public MinWithStatusAttribute(int minValue)
    {
        _minValue = minValue;
    }

    public override HttpParameterBinding GetBinding(HttpParameterDescriptor parameter) => new MinWithStatusParameterBinding(parameter, _minValue);
}

public class MinWithStatusParameterBinding : HttpParameterBinding, IValueProviderParameterBinding
{
    private readonly int _minValue;
    public HttpParameterBinding DefaultUriBinding; 

    public MinWithStatusParameterBinding(HttpParameterDescriptor desc, int minValue)
        : base(desc)
    {
        _minValue = minValue;
        var defaultUrl = new FromUriAttribute();
        this.DefaultUriBinding = defaultUrl.GetBinding(desc);
        this.ValueProviderFactories = defaultUrl.GetValueProviderFactories(desc.Configuration);
    }


    public override Task ExecuteBindingAsync(ModelMetadataProvider metadataProvider, HttpActionContext actionContext, CancellationToken cancellationToken)
    {
        return DefaultUriBinding.ExecuteBindingAsync(metadataProvider, actionContext, cancellationToken).ContinueWith((tsk) =>
        {
            var currentBoundValue = this.GetValue(actionContext);
            if (!(currentBoundValue is int)) return; //if it is not an Int, return.
            var currentBoundInt = (int)currentBoundValue;
            if (currentBoundInt >= _minValue) return; //If the value provided is greater than or equal to the min value, return. Else throw an error
            var preconditionFailedResponse = actionContext.Request.CreateResponse(HttpStatusCode.PreconditionFailed, $"The parameter {DefaultUriBinding.Descriptor.ParameterName} must be greater than or equal to {_minValue}" });
            throw new HttpResponseException(preconditionFailedResponse);
        }, cancellationToken);
    }

    public IEnumerable<ValueProviderFactory> ValueProviderFactories { get; } //IValueProviderParameterBinding
}

这是一个整数，但您可以轻松修改它以使用字符串正则表达式。现在它可以应用于您的查询参数：

public IHttpActionResult SendEmailToCandidate(int id, [MinWithStatus(3)]int company_id, [MinWithStatus(3)]int recruiter_id, string subject, string body)
    {
        //Do stuff in your controller method. If they enter less than 3 it will display an error with Http status code 412 precondition failed.
    }

Answer 2

如果您使用属性路由来管理进入控制器的路径，你可以做这样的事情：

[Route("{Id:regex([0-9]{0,10})}")]
public async Task<HttpResponseMessage> Get(string id)
{

}

Attribute Routing overview documentation中记载了各种路线约束。

它确实提出了一个问题，即为什么您要接受长度为10的数字字符串作为您的ID。在将其解析为不超过2,147,483,647的int时，您必须要小心，因为它是默认整数的最大大小。

使用验证属性的Web API单字符串参数验证

2 个答案: