在Web API中使用数组作为参数时出现不受支持的媒体类型错误？

Question

我遇到了我在Web Api中从未见过的新错误

Response = StatusCode: 415, ReasonPhrase: 'Unsupported Media Type', Version: 1.1, Content: System.Net.Http.ObjectContent`1[[System.Web.Http.HttpError, System.Web.Http, Version=5.2.7.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]], Headers:  {    Content-Type: application/json; charset=utf-8  } Message = Processing of the HTTP request resulted in an exception. Please see the HTTP response returned by the 'Response' property of this exception for details. Data = System.Collections.ListDictionaryInternal InnerException =  TargetSite = System.Threading.Tasks.Task`1[System.Object] ReadContentAsync(System.Net.Http.HttpRequestMessage, System.Type, System.Collections.Generic.IEnumerable`1[System.Net.Http.Formatting.MediaTypeFormatter], System.Net.Http.Formatting.IFormatterLogger, System.Threading.CancellationToken) StackTrace =    at System.Web.Http.ModelBinding.FormatterParameterBinding.ReadContentAsync(HttpRequestMessage request, Type type, IEnumerable`1 formatters, IFormatterLogger formatterLogger, CancellationToken cancellationToken)     at System.Web.Http.ModelBinding.FormatterParameterBinding.ReadContentAsync(HttpRequestMessage request, Type type, IEnumerable`1 formatters, IFormatterLogger formatterLogger)     at System.Web.Http.ModelBinding.FormatterParameterBinding.<ExecuteBindingAsyncCore>d__18.MoveNext()  --- End of stack trace from previous location where exception was thrown ---     at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)     at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)     at System.Web.Http.Controllers.HttpActionBinding.<ExecuteBindingAsyncCore>d__12.MoveNext()  --- End of stack trace from previous location where exception was thrown ---     at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)     at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)     at System.Web.Http.Controllers.ActionFilterResult.<ExecuteAsync>d__5.MoveNext()  --- End of stack trace from previous location where exception was thrown ---     at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)     at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)     at System.Web.Http.Controllers.ExceptionFilterResult.<ExecuteAsync>d__6.MoveNext() HelpLink =  Source = System.Web.Http HResult = -2146233088

这是控制器内部的动作

[HttpGet]
[Route("show_many")]
[ArrayInput("ids", Separator = ',')]
public async Task<HttpResponseMessage> GetByIds(int[] ids)
{
}

似乎执行未达到ArrayInput或方法GetByIds。 我相信int数组会导致此问题作为参数。 当我执行基本邮递员请求时，一切正常。

我正在通过HttpClient从SDK调用此终结点。 我也尝试在客户端标头中设置content-type，例如

client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));

但这也没有帮助。

Uri看起来像http://example.com/show_many?ids=1,2,3

这里有什么问题？

更新

我注意到，此错误发生在Microsofot.AspNet.WebApi 5.2.7中，但未在5.2.3中发生。

此外，我注意到client.DefaultRequestHeaders.Accept.Add（new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue（“ application / json”））; 仅创建Accept标头，而不创建Content-Type。 Content-type应该是一个响应头，但是不幸的是，仅将content-type添加到请求头实际上会绕过此问题（在邮递员中）。

Answer 1

可能您的Accept标头与415无关。请确保您正确地形成了url。

您也可以指定[FromUri]进行参数设置，并像api?ids[]=1&ids[]=2一样构建您的uri。 看到这个答案 。

或者，如果您想进一步控制uri的形成方式，请查看以下答案。

https://stackoverflow.com/a/17553324/1083512

Answer 2

问题是[ArrayInput（“ ids”，Separator ='，'）]及其与WebApi 5.2.7不兼容。

Answer 3

传递数组参数时：应将其连接为JSON格式的字符串，然后在将数组参数值传递给WebAPI接口之前，调用jQuery将字符串转换为JSON。