asp.net - 为什么在 ASP.Net 中向 StatusDescription 添加换行符会关闭连接？

Question

当我使用 ASP.Net MVC 3.0 中的 HttpStatusCodeResult 返回带有换行符的 StatusDescription 时，与我的客户端的连接被强制关闭。应用程序托管在 IIS 7.0 中。

示例 Controller :

 public class FooController : Controller
 {
    public ActionResult MyAction()
    {
       return new HttpStatusCodeResult((int)HttpStatusCode.BadRequest, "Foo \n Bar");
    }
 }

示例客户端:

using (WebClient client = new WebClient())
{
   client.DownloadString("http://localhost/app/Foo/MyAction");
}

抛出异常:

System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a receive. 
  System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.
    System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host

使用 curl (curl 7.25.0 (i386-pc-win32) libcurl/7.25.0 zlib/1.2.6) 时的行为是一致的

curl http://localhost/app/Foo/MyAction

curl:(56)接收失败:连接已重置

编辑

我最终使用此自定义 ActionResult 来获得所需的结果。

public class BadRequestResult : ActionResult
{
   private const int BadRequestCode = (int)HttpStatusCode.BadRequest;
   private int count = 0;

   public BadRequestResult(string errors)
      : this(errors, "")
   {
   }

   public BadRequestResult(string format, params object[] args)
   {
      if (String.IsNullOrEmpty(format))
      {
         throw new ArgumentException("format");
      }

      Errors = String.Format(format, args);

      count = Errors.Split(new string[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries).Length;
   }

   public string Errors { get; private set; }

   public override void ExecuteResult(ControllerContext context)
   {
      if (context == null)
      {
         throw new ArgumentNullException("context");
      }

      HttpResponseBase response = context.HttpContext.Response;
      response.TrySkipIisCustomErrors = true;
      response.StatusCode = BadRequestCode;
      response.StatusDescription = String.Format("Bad Request {0} Error(s)", count);
      response.Write(Errors);
      response.End();
   }
}

Answer 1

HTTP header 中间不能有换行符。

HTTP 协议(protocol)指定 header 的结尾是换行符。

由于换行符位于 header 中间，因此 header 不是有效 header ，您会收到此错误。

修复:不要在 HTTP header 中间放置换行符。