爲什麼在ASP.Net中向StatusDescription添加一個換行符會關閉連接？

Question

當我使用ASP.Net MVC 3.0中的HttpStatusCodeResult返回帶有換行符的StatusDescription時，與我的客戶端的連接被強制關閉。應用程序位於IIS 7.0中。

實施例的控制器：

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

實施例的客戶端：

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

引發的異常：使用捲曲（捲曲7.25.0（I386-PC時

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 

的行爲是一致的-win32）libcurl/7.25.0 zlib/1.2.6）

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

捲曲：（56）的Recv失敗：連接被重置

編輯

最後我用這個自定義的ActionResult來得到想要的結果。

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

在HTTP標頭的中間不能有換行符。

HTTP協議指定標題的結尾是換行符。

因爲換行符位於標題的中間，所以標題不是有效的標題，並且出現此錯誤。

修復：不要在HTTP標頭的中間放置換行符。