在ASP.NET Web API中處理ModelState驗證

Question

我想知道如何使用ASP.NET Web API實現模型驗證。我有我的模型，像這樣：

public class Enquiry 
{ 
    [Key] 
    public int EnquiryId { get; set; } 
    [Required] 
    public DateTime EnquiryDate { get; set; } 
    [Required] 
    public string CustomerAccountNumber { get; set; } 
    [Required] 
    public string ContactName { get; set; } 
} 

然後我有一個郵政行動在我的API控制器：

public void Post(Enquiry enquiry) 
{ 
    enquiry.EnquiryDate = DateTime.Now; 
    context.DaybookEnquiries.Add(enquiry); 
    context.SaveChanges(); 
} 

如何添加if(ModelState.IsValid)然後處理錯誤消息向下傳遞給用戶？

Answer 1

關注的分離，我會建議你使用行爲過濾模型驗證，所以你不需要關心太多怎麼辦確認在您的API控制器：

using System.Net; 
using System.Net.Http; 
using System.Web.Http.Controllers; 
using System.Web.Http.Filters; 

namespace System.Web.Http.Filters 
{ 
    public class ValidationActionFilter : ActionFilterAttribute 
    { 
     public override void OnActionExecuting(HttpActionContext actionContext) 
     { 
      var modelState = actionContext.ModelState; 

      if (!modelState.IsValid) 
       actionContext.Response = actionContext.Request 
        .CreateErrorResponse(HttpStatusCode.BadRequest, modelState); 
     } 
    } 
} 

Answer 2

這樣，例如：

public HttpResponseMessage Post(Person person) 
{ 
    if (ModelState.IsValid) 
    { 
     PersonDB.Add(person); 
     return Request.CreateResponse(HttpStatusCode.Created, person); 
    } 
    else 
    { 
     // the code below should probably be refactored into a GetModelErrors 
     // method on your BaseApiController or something like that 

     var errors = new List<string>(); 
     foreach (var state in ModelState) 
     { 
      foreach (var error in state.Value.Errors) 
      { 
       errors.Add(error.ErrorMessage); 
      } 
     } 
     return Request.CreateResponse(HttpStatusCode.Forbidden, errors); 
    } 
} 

這將返回這樣的響應（假設JSON，但XML基本原理相同）：

HTTP/1.1 400 Bad Request 
Content-Type: application/json; charset=utf-8 
(some headers removed here) 

["A value is required.","The field First is required.","Some custom errorm essage."] 

當然你也可以建立你的錯誤對象/列出你喜歡的任何方式，例如添加字段名，字段的ID等

即使它是一個「單向」 Ajax調用像一個新的實體的POST，你還是應該返回的東西給調用者 - 指示請求是否成功。想象一下你的用戶將通過AJAX POST請求添加一些關於他們自己的信息的網站。如果他們試圖輸入的信息無效 - 他們如何知道他們的保存操作是否成功？

執行此操作的最佳方法是使用良好的舊的HTTP狀態碼，如200 OK等。這樣，你的JavaScript就可以使用正確的回調（錯誤，成功等）正確處理失敗。

下面是關於這種方法的更高級版本的一個很好的教程，用一個ActionFilter和jQuery：http://asp.net/web-api/videos/getting-started/custom-validation

Answer 3

也許不是你要找的，但也許是不錯的人知道：

如果您使用的是.NET網絡API 2你可以只需做下面的事情G：

if (!ModelState.IsValid) 
    return BadRequest(ModelState); 

根據模型的錯誤，你會得到這樣的結果：

{ 
    Message: "The request is invalid." 
    ModelState: { 
     model.PropertyA: [ 
      "The PropertyA field is required." 
     ], 
     model.PropertyB: [ 
      "The PropertyB field is required." 
     ] 
    } 
} 

Answer 4

你也可以拋出異常，如記錄在這裏： http://blogs.msdn.com/b/youssefm/archive/2012/06/28/error-handling-in-asp-net-webapi.aspx

注意，要做到這一點文章提出什麼，請記住，包括System.Net.Http

Answer 5

您可以使用屬性從System.ComponentModel.DataAnnotations命名空間來設置驗證規則。詳情請參閱Model Validation - By Mike Wasson。

另請參閱視頻ASP.NET Web API, Part 5: Custom Validation - Jon Galloway

其他參考資料

1. Take a Walk on the Client Side with WebAPI and WebForms
2. How ASP.NET Web API binds HTTP messages to domain models, and how to work with media formats in Web API.
3. Dominick Baier - Securing ASP.NET Web APIs
4. Hooking AngularJS validation to ASP.NET Web API Validation
5. Displaying ModelState Errors with AngularJS in ASP.NET MVC
6. How to render errors to client? AngularJS/WebApi ModelState
7. Dependency-Injected Validation in Web API

Answer 6

我不得不實施一個問題accepted solution pattern在我的ModelStateFilter總是返回false（以及隨後400），用於actionContext.ModelState.IsValid某些模型對象：

public class ModelStateFilter : ActionFilterAttribute 
{ 
    public override void OnActionExecuting(HttpActionContext actionContext) 
    { 
     if (!actionContext.ModelState.IsValid) 
     { 
      actionContext.Response = new HttpResponseMessage { StatusCode = HttpStatusCode.BadRequest}; 
     } 
    } 
} 

我只接受JSON，所以我實現了一個自定義模型綁定器類：

public class AddressModelBinder : System.Web.Http.ModelBinding.IModelBinder 
{ 
    public bool BindModel(HttpActionContext actionContext, System.Web.Http.ModelBinding.ModelBindingContext bindingContext) 
    { 
     var posted = actionContext.Request.Content.ReadAsStringAsync().Result; 
     AddressDTO address = JsonConvert.DeserializeObject<AddressDTO>(posted); 
     if (address != null) 
     { 
      // moar val here 
      bindingContext.Model = address; 
      return true; 
     } 
     return false; 
    } 
} 

這一點我通過

config.BindParameter(typeof(AddressDTO), new AddressModelBinder()); 

Answer 7

這裏我的模型後，直接註冊，您可以檢查一個

public HttpResponseMessage CertificateUpload(employeeModel emp) 
    { 
     if (!ModelState.IsValid) 
     { 
      string errordetails = ""; 
      var errors = new List<string>(); 
      foreach (var state in ModelState) 
      { 
       foreach (var error in state.Value.Errors) 
       { 
        string p = error.ErrorMessage; 
        errordetails = errordetails + error.ErrorMessage; 

       } 
      } 
      Dictionary<string, object> dict = new Dictionary<string, object>(); 



      dict.Add("error", errordetails); 
      return Request.CreateResponse(HttpStatusCode.BadRequest, dict); 


     } 
     else 
     { 
     //do something 
     } 
     } 

}

Answer 8

C＃

顯示模型的狀態誤差一個

public class ValidateModelAttribute : ActionFilterAttribute 
    { 
     public override void OnActionExecuting(HttpActionContext actionContext) 
     { 
      if (actionContext.ModelState.IsValid == false) 
      { 
       actionContext.Response = actionContext.Request.CreateErrorResponse(
        HttpStatusCode.BadRequest, actionContext.ModelState); 
      } 
     } 
    } 

...

[ValidateModel] 
    public HttpResponseMessage Post([FromBody]AnyModel model) 
    { 

的Javascript

$.ajax({ 
     type: "POST", 
     url: "/api/xxxxx", 
     async: 'false', 
     contentType: "application/json; charset=utf-8", 
     data: JSON.stringify(data), 
     error: function (xhr, status, err) { 
      if (xhr.status == 400) { 
       DisplayModelStateErrors(xhr.responseJSON.ModelState); 
      } 
     }, 
.... 


function DisplayModelStateErrors(modelState) { 
    var message = ""; 
    var propStrings = Object.keys(modelState); 

    $.each(propStrings, function (i, propString) { 
     var propErrors = modelState[propString]; 
     $.each(propErrors, function (j, propError) { 
      message += propError; 
     }); 
     message += "\n"; 
    }); 

    alert(message); 
}; 

Answer 9

或者，如果您正在爲您的應用程序錯誤的簡單集合..這是我實現這一點：

public override void OnActionExecuting(HttpActionContext actionContext) 
    { 
     var modelState = actionContext.ModelState; 

     if (!modelState.IsValid) 
     { 

      var errors = new List<string>(); 
      foreach (var state in modelState) 
      { 
       foreach (var error in state.Value.Errors) 
       { 
        errors.Add(error.ErrorMessage); 
       } 
      } 

      var response = new { errors = errors }; 

      actionContext.Response = actionContext.Request 
       .CreateResponse(HttpStatusCode.BadRequest, response, JsonMediaTypeFormatter.DefaultMediaType); 
     } 
    } 

錯誤消息響應將如下所示：

{ 
    "errors": [ 
    "Please enter a valid phone number (7+ more digits)", 
    "Please enter a valid e-mail address" 
    ] 
}