尝试从 FitNesse REST URI 读取响应时出现连接关闭错误

Question

你遇到过这个问题吗？我运行的代码与 上一个问题，当处于 nUnitTest 模式且 URI 包含“/?test&format=xml”时，nUnit 测试失败并出现 IOException，“无法从传输连接读取数据：连接已关闭。”

然而，当时运行的 Fiddler 跟踪显示了我所期望的 xml。

我已经（几乎）完全按照通过浏览器发送请求标头的方式重新创建了请求标头。

最后，如果我从 URI 中去掉“/?test&format=xml”，我就会得到我原本期望的 html。

源代码：

    public virtual bool Run()
    {
        var request = CreateRequest();
        var response = GetResponse(request);
        var responseString = ReadResponse(response);
        this.SetResults(responseString);
        return this.IsSuccessful;
    }

    protected internal virtual HttpWebRequest CreateRequest()
    {
        var address = TestConfig.Address;

        var request = (HttpWebRequest)WebRequest.Create(address);

        request.Accept = "*/*";
        request.UseDefaultCredentials = true;
        request.CachePolicy = new RequestCachePolicy(RequestCacheLevel.NoCacheNoStore);

        return request;
    }

    protected internal virtual HttpWebResponse GetResponse(HttpWebRequest request)
    {
        var response = (HttpWebResponse) request.GetResponse();

        return response;
    }

    protected internal virtual string ReadResponse(HttpWebResponse response)
    {
        var stream = response.GetResponseStream();
        var responseString = ReadResponse(stream);

        stream.Close();
        response.Close();

        return responseString;
    }

    protected internal virtual string ReadResponse(Stream stream)
    {
        var reader = new StreamReader(stream);
        var responseString = reader.ReadToEnd();
        return responseString;
    }

Answer 1

错误消息“无法从传输连接读取数据：连接已关闭。”与您看到 Fiddler 获取 html 响应正文的事实并没有真正联系起来。

检查 HttpWebResponse 的 StatusCode（如果正常，应为 200），还将请求包装在 try/catch 块中（示例来自 http://msdn.microsoft.com/en-us/library/system.net.httpwebresponse.statuscode(v=vs.80) .aspx）

try 
   {    
        // Creates an HttpWebRequest for the specified URL. 
        HttpWebRequest myHttpWebRequest = (HttpWebRequest)WebRequest.Create(url); 
        // Sends the HttpWebRequest and waits for a response.
        HttpWebResponse myHttpWebResponse = (HttpWebResponse)myHttpWebRequest.GetResponse(); 
        if (myHttpWebResponse.StatusCode == HttpStatusCode.OK)
           Console.WriteLine("\r\nResponse Status Code is OK and StatusDescription is: {0}",
                                myHttpWebResponse.StatusDescription);
        // Releases the resources of the response.
        myHttpWebResponse.Close(); 

    } 
catch(WebException e) 
   {
        Console.WriteLine("\r\nWebException Raised. The following error occured : {0}",e.Status); 
   }
catch(Exception e)
{
    Console.WriteLine("\nThe following Exception was raised : {0}",e.Message);
}

如果您快速创建和处置 HttpWebRequest 对象，您可能会在套接字关闭时进入 time_wait 状态，然后您无法重新打开它，直到它完全关闭关闭。如果是这种情况，请考虑使用其他端口或更改连接的生存时间。