使用验证属性的Web API单字符串参数验证

Question

我知道您可以在模型上使用Validation属性来验证它,如下所示:

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)
{

}

但是可以使用诸如此类的验证属性来验证单个字符串吗？

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一个包装器对象并使用[FromUri],ActionFilterAttribute在操作本身上使用自定义或使用正则表达式手动验证控制器操作中的参数.

Answer 1

如果您使用属性路由来管理进入控制器的路径，您可以随时执行以下操作：

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

}

有各种路由限制，如属性路由概述文档中所述。

它确实提出了一个问题，即为什么您接受长度为 10 的数字字符串作为您的 ID。将其解析为不超过的 int 时必须小心2,147,483,647，因为这是默认整数的最大大小。

Answer 2

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.
    }