使用BadRequest（WebApi）返回错误列表

Question

正如标题所示，我想要做的就是在“模型”不完整的情况下返回自定义的错误集合。

虽然积极地“SO'ing /谷歌搜索”，但我还没有找到解决方案来帮助解决我的问题。

我可以使用“ModelState”，但由于“自定义”，我想手动执行此操作。

代码如下：

API级别

// POST api/<controller>
[HttpPost]
[Route("")]
public async Task<IHttpActionResult> Post([FromBody]Order order)
{
    var modelResponse = new ModelResponse<Order>(order);
    if (order == null)
        return BadRequest("Unusable resource, object instance required.");

    //Check if all required properties contain values, if not, return response
    //with the details
    if (!modelResponse.IsModelValid())
        return this.PropertiesRequired(modelResponse.ModelErrors());

    try
    {
        await _orderService.AddAsync(order);
    }
    catch (System.Exception ex)
    {
        return InternalServerError();
    }
    finally
    {
        _orderService.Dispose();
    }

    return Ok("Order Successfully Processed.");
}

属性必需的操作结果

public List<string> Messages { get; private set; }
public HttpRequestMessage Request { get; private set; }

public PropertiesRequiredActionResult(List<string> message, 
    HttpRequestMessage request)
{
    this.Messages = message;
    this.Request = request;
}
public Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken)
{
    return Task.FromResult(Execute());
}

public HttpResponseMessage Execute()
{
    HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.BadRequest);
    response.Content = new ObjectContent()
        //new List<StringContent>(Messages); //Stuck here
    response.RequestMessage = Request;
    return response;
}

根据自定义属性查找不完整的属性

private T _obj;

public ModelResponse(T obj)
{
    _obj = obj;
}

private Dictionary<string, object> GetPropertyAttributes(PropertyInfo property)
{
    Dictionary<string, object> attribs = new Dictionary<string, object>();
    // look for attributes that takes one constructor argument
    foreach (CustomAttributeData attribData in property.GetCustomAttributesData())
    {

        if (attribData.ConstructorArguments.Count == 1)
        {
            string typeName = attribData.Constructor.DeclaringType.Name;
            if (typeName.EndsWith("Attribute")) typeName = typeName.Substring(0, typeName.Length - 9);
            attribs[typeName] = attribData.ConstructorArguments[0].Value;
        }

    }
    return attribs;
}
private IEnumerable<PropertyInfo> GetProperties()
{
    var props = typeof(T).GetProperties().Where(
            prop => Attribute.IsDefined(prop, typeof(APIAttribute)));

    return props;
}
public bool IsModelValid()
{
    var props = GetProperties();
    return props.Any(p => p != null);
}
public List<string> ModelErrors()
{
        List<string> errors = new List<string>();
        foreach (var p in GetProperties())
        {

            object propertyValue = _obj.GetType()
                .GetProperty(p.Name).GetValue(_obj, null);

            if (propertyValue == null)
            {
                errors.Add(p.Name + " - " + GetPropertyAttributes(p).FirstOrDefault());
            }
        }
        return errors;
}

属性样本

/// <summary>
/// The date and time when the order was created.
/// </summary>
[API(Required = "Order Created At Required")]
public DateTime Order_Created_At { get; set; }

因此，忽略后两个片段，更多的是提供完整的流程概述。 我完全理解有一些“开箱即用”的技术，但我喜欢自己设计。

到目前为止，是否可以使用“BadRequest”返回错误列表？

非常感激。

Answer 1

您可能正在寻找使用此方法：

BadRequestObjectResult BadRequest(ModelStateDictionary modelState)

它的用法是这样的，例子来自SO中的另一个问题 ：

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

根据模型错误，您会得到以下结果：

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

希望能帮助到你

Answer 2

在IHttpActionResult的自定义实现中，使用请求创建响应并传递模型和状态代码。

public List<string> Messages { get; private set; }
public HttpRequestMessage Request { get; private set; }

public HttpResponseMessage Execute() {
    var response = Request.CreateResponse(HttpStatusCode.BadRequest, Messages);
    return response;
}

Answer 3

我知道从这篇文章发布之日起就已经很晚了，以防其他人有同样的需求。

我是这样做的：

public object GetModelStateErrors(ModelStateDictionary modelState)
    {
        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 };

        return response;
    }

正如您所见， GetModelStateErrors是一个函数，它返回一个字符串数组，其中包含您已收到的错误集合，并接收ModelState对象以从中获取这些错误。

我这样实现了：

return Request.CreateResponse(HttpStatusCode.BadRequest, GetModelStateErrors(ModelState))

我使用Insomnia的反应是：

{
    "errors": [
        "The Correo field is required.",
        "The Telefono field is required."
    ]
}

希望有所帮助