底层连接已关闭：服务器违反了协议。FTP

Question

我正在使用以下代码上传文件，它工作得很好，但有时会抛出错误“The underlying connection was closed: The server committed a protocol violation”，并停止进程，当我再次运行它时，它可以顺利上传文件。

有一件事我注意到，如果我运行这个进程来上传多个文件，那么我有时会遇到这个错误。如果我上传的文件少于5个，那么它就可以正常工作。您有什么想法，我应该在哪里查找问题？

我在谷歌上搜索，没有找到一个确定的解决方案，甚至其中一个msdn博客说这是FTPwebrequest中的一个bug，但不确定。

环境：C#4.0，IIS FTP服务器。

提前感谢！

                FileInfo fileInf = new FileInfo(filename);
                FtpWebRequest reqFTP;

                // Create FtpWebRequest object from the Uri provided
                reqFTP = (FtpWebRequest)FtpWebRequest.Create
                         (new Uri(path + fileInf.Name));


                // Provide the WebPermission Credintials
                 reqFTP.Credentials = new NetworkCredential(user, pwd);

                // By default KeepAlive is true, where the control connection
                // is not closed after a command is executed.
                reqFTP.KeepAlive = false;


                // Specify the command to be executed.
                reqFTP.Method = WebRequestMethods.Ftp.UploadFile;

                // Specify the data transfer type.
                reqFTP.UseBinary = true;
                reqFTP.Timeout = -1;
                reqFTP.UsePassive = true;


                // Notify the server about the size of the uploaded file
                reqFTP.ContentLength = fileInf.Length;

                // The buffer size is set to 2kb
                int buffLength = 4096;
                byte[] buff = new byte[buffLength];
                int contentLen;

                // Opens a file stream (System.IO.FileStream) to read the file
                // to be uploaded
                FileStream fs = fileInf.OpenRead();


                try
                {
                    // Stream to which the file to be upload is written
                    Stream strm = reqFTP.GetRequestStream();

                    // Read from the file stream 2kb at a time
                    contentLen = fs.Read(buff, 0, buffLength);

                    // Till Stream content ends
                    while (contentLen != 0)
                    {
                        // Write Content from the file stream to the FTP Upload
                        // Stream
                        strm.Write(buff, 0, contentLen);
                        contentLen = fs.Read(buff, 0, buffLength);
                    }

                    // Close the file stream and the Request Stream
                    strm.Close();
                    fs.Close();
                }

答案

在我的情况下，将reqFTP.KeepAlive设置为"True"可以消除错误。

- Usher

Answer 1

将reqFTP.KeepAlive = false;更改为"reqFTP.KeepAlive = True;"以消除错误。

- Usher

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我尝试过了，仍然得到相同的错误。还有什么其他问题吗？ - eran otzap