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在ASP中识别模型绑定失败的最佳方法是什么。NET Core 6.0+

model-validation model-binding asp.net-core-webapi asp.net-core c#

2

phougatv · 技术社区 · 3 年前

我已经浏览了MSDN文档:

我尝试创建一个场景,其中从swagger发送到API的值无法绑定到服务器上预期的模型。以下是场景的代码:

OrderController.cs

[HttpPost]
public async Task<IActionResult> CreateAsync(OrderViewModel viewModel)
{
    //map and add this model to the db
    //and return a 201 status code
}

还有我从招摇中发出的信息:

{
    null
}

这导致了模型绑定失败,我有一个结果过滤器,用于处理这种情况,如下所示: FailedValidationResultFilter

public class FailedValidationResultFilter : IResultFilter
{
    public void OnResultExecuted(ResultExecutedContext context)
    {
    }

    public void OnResultExecuting(ResultExecutingContext context)
    {
        //When model-binding fails
        var hasModelBindingFailed = context.ModelState.Any(pair => String.IsNullOrEmpty(pair.Key));
        if (hasModelBindingFailed)
        {
            //do something when model-binding fails.
            //and return BadRequestObjectResult
        }

        //When validation attributes fails
        var invalidParams = new Dictionary<String, String[]>(context.ModelState.Count);
        foreach (var keyModelStatePair in context.ModelState)
        {
            var key = keyModelStatePair.Key;
            var modelErrors = keyModelStatePair.Value.Errors;

            if (modelErrors is not null && modelErrors.Count > 0)
            {
                var errorMessages = modelErrors.Select(error => error.ErrorMessage).ToArray();
                invalidParams.Add(key, errorMessages);
            }
        }

        var problemDetails = new ProblemDetails
        {
            Type = "123",
            Title = "Invalid parameters",
            Status = StatusCodes.Status400BadRequest,
            Detail = "Your request parameters didn't validate.",
            Instance = ""
        };
        problemDetails.Extensions.Add(nameof(invalidParams), invalidParams);

        context.Result = new BadRequestObjectResult(problemDetails);
    }
}

我在调试时观察到,每当此输入的模型绑定失败时,它都会返回2个键值对:

{ "", "Some error message" }
{ "viewModel", "Again some error message" }

所以,我正在检查它们是否是一个带有空键的模型状态,如果是,则存在模型绑定错误。我不知道为什么,但这似乎不是发现模型绑定是否失败的正确方法。

问题:识别模型绑定是否失败的正确方法是什么?可以传递的另一种输入类型是什么,这会导致模型绑定失败,然后在过滤器中,第一个属性可能不会像我预期的那样为空?

0 回复 | 直到 3 年前

1

0

Qiang Fu 3 年前

ModelState.key是无效的属性名称。你发送 null 因此属性名称为空。但在我的测试中,关键是一个“$”
您可以尝试以下代码。
ViewModel.cs

    public class ViewModel
    {
        public int Number {  get; set; }
    }

ProblemDetails.cs

    public class ProblemDetails
    {
        public string Type { get; set; }
        public string Title { get; set; }
        public int Status { get; set; }
        public string Detail { get; set; }
        public string Instance { get; set; }
        public Dictionary<string, string> Extensions { get; set; }
    }

程序.cs

builder.Services.Configure<ApiBehaviorOptions>(options
    => options.SuppressModelStateInvalidFilter = true);

控制器

        [HttpPost("test")]
        public IActionResult test(ViewModel viewModel)
        {
            if (!ModelState.IsValid)
            {
                var problemDetails = new ProblemDetails
                {
                    Type = "123",
                    Title = "Invalid parameters",
                    Status = StatusCodes.Status400BadRequest,
                    Detail = "Your request parameters didn't validate.",
                    Instance = "",
                    Extensions = new Dictionary<string, string>()
                };
                foreach (var b in ModelState)
                {
                    problemDetails.Extensions.Add(b.Key, b.Value.Errors.FirstOrDefault().ErrorMessage);
                }
                return Ok(problemDetails);
            }
            return Ok(viewModel);           
        }

测验

您可以将代码放在ActionFilter中。
ValidationFilterAttribute.cs

    public class ValidationFilterAttribute : IActionFilter
    {
        public void OnActionExecuting(ActionExecutingContext context)
        {
            if (!context.ModelState.IsValid)
            {
                var problemDetails = new ProblemDetails
                {
                    Type = "123",
                    Title = "Invalid parameters",
                    Status = StatusCodes.Status400BadRequest,
                    Detail = "Your request parameters didn't validate.",
                    Instance = "",
                    Extensions = new Dictionary<string, string>()
                };
                foreach (var b in context.ModelState)
                {
                    problemDetails.Extensions.Add(b.Key, b.Value.Errors.FirstOrDefault().ErrorMessage);
                }
                context.Result = new ObjectResult(problemDetails);
            }
        }
        public void OnActionExecuted(ActionExecutedContext context) { }
    }

程序.cs

builder.Services.AddScoped<ValidationFilterAttribute>();
builder.Services.Configure<ApiBehaviorOptions>(options
    => options.SuppressModelStateInvalidFilter = true);

控制器

        [HttpPost("test")]
        [ServiceFilter(typeof(ValidationFilterAttribute))]
        public IActionResult test(ViewModel viewModel)
        {
            return Ok(viewModel);           
        }

结果过滤器与操作过滤器 ActionFilter and ResultFilter different and Examples

2

0

phougatv 3 年前

经过大量的测试和试验,我希望我有正确的答案。那么,让我们开始吧。

场景一

当请求有效载荷为

null

当我们在请求中发送此有效载荷时,模型验证无法生成2个密钥( 其中一个是空字符串 )带有以下错误消息:

钥匙	错误消息
	需要一个非空的请求正文。
视图模型	viewModel字段是必需的。

场景二

当请求有效载荷为

{
    null
}

在这种情况下,将生成这2个密钥:

钥匙	错误消息
$	“n”是属性名称的无效开头。应为“”。路径:$\|行号:1 \| BytePositionInLine:2。
视图模型	viewModel字段是必需的。

现在,我已经使用以下代码来处理这两种场景:

//When model-binding fails because input is an invalid JSON
if (modelStateDictionary.Any(pair => pair.Key == DollarSign || String.IsNullOrEmpty(pair.Key)))
{
    problemDetails.Detail = RequestFailedModelBinding;
    context.Result = GetBadRequestObjectResult(problemDetails);
    return;
}

完整代码:

using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Filters;
using WebApi.ErrorResponse.ViaFilterAndMiddleware.ViewModels;
using static Microsoft.AspNetCore.Http.StatusCodes;

public class MyModelValidationResultFilter : IResultFilter
{
    #region Private Constants
    private const Char Dot = '.';
    private const String DollarSign = "$";
    private const String InvalidParameters = "Invalid parameters.";
    private const String RequestFailedModelBinding = "Your request failed model-binding.";
    private const String RequestPropertyFailedModelBinding = "Your request failed model-binding: '{0}'.";
    private const String RequestParametersDidNotValidate = "Your request parameters did not validate.";
    private const String MediaTypeApplicationProblemJson = "application/problem+json";
    #endregion Private Constants

    /// <summary>
    /// 
    /// </summary>
    /// <param name="context">The result executed context.</param>
    public void OnResultExecuted(ResultExecutedContext context)
    {

    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="context">The result executing context.</param>
    public void OnResultExecuting(ResultExecutingContext context)
    {
        if (context.ModelState.IsValid)
            return;

        var modelStateDictionary = context.ModelState;
        var problemDetails = new ProblemDetails
        {
            Title = InvalidParameters,
            Status = Status400BadRequest
        };

        //When model-binding fails because input is an invalid JSON
        if (modelStateDictionary.Any(pair => pair.Key == DollarSign || String.IsNullOrEmpty(pair.Key)))
        {
            problemDetails.Detail = RequestFailedModelBinding;
            context.Result = GetBadRequestObjectResult(problemDetails);
            return;
        }

        //When a specific property-binding fails
        var keyValuePair = modelStateDictionary.FirstOrDefault(pair => pair.Key.Contains("$."));
        if (keyValuePair.Key is not null)
        {
            var propertyName = keyValuePair.Key.Split(Dot)[1];
            problemDetails.Detail =
                String.IsNullOrEmpty(propertyName) ? RequestFailedModelBinding : String.Format(RequestPropertyFailedModelBinding, propertyName);
            context.Result = GetBadRequestObjectResult(problemDetails);
            return;
        }

        //When one of the input parameters failed model-validation
        var invalidParams = new List<InvalidParam>(modelStateDictionary.Count);
        foreach (var keyModelStatePair in modelStateDictionary)
        {
            var key = keyModelStatePair.Key;
            var modelErrors = keyModelStatePair.Value.Errors;
            if (modelErrors is not null && modelErrors.Count > 0)
            {
                IEnumerable<InvalidParam> invalidParam;
                if (modelErrors.Count == 1)
                {
                    invalidParam = modelErrors.Select(error => new InvalidParam(keyModelStatePair.Key, new[] { error.ErrorMessage }));
                }
                else
                {
                    var errorMessages = new String[modelErrors.Count];
                    for (var i = 0; i < modelErrors.Count; i++)
                    {
                        errorMessages[i] = modelErrors[i].ErrorMessage;
                    }

                    invalidParam = modelErrors.Select(error => new InvalidParam(keyModelStatePair.Key, errorMessages));
                }

                invalidParams.AddRange(invalidParam);
            }
        }

        problemDetails.Detail = RequestParametersDidNotValidate;
        problemDetails.Extensions[nameof(invalidParams)] = invalidParams;
        context.Result = GetBadRequestObjectResult(problemDetails);
    }

    /// <summary>
    /// Creates <see cref="BadRequestObjectResult"/> instance.
    /// The content-type is set to: 'application/problem+json'
    /// </summary>
    /// <param name="problemDetails">The problem details instance.</param>
    /// <returns>The bad request object result instance.</returns>
    private static BadRequestObjectResult GetBadRequestObjectResult(ProblemDetails problemDetails)
    {
        var result = new BadRequestObjectResult(problemDetails);
        result.ContentTypes.Clear();
        result.ContentTypes.Add(MediaTypeApplicationProblemJson);
        return result;
    }
}