FTP上载文件使用HTTP代理时不支持请求的FTP命令

Question

Can someone please take a look at the code below and tell me what I am doing wrong. I am just going in circles,,, any pointers greatly appreciated

public class FtpWebRequestUtil
{
    private static string RemoteHost;
    private static string RemoteFtpPath;
    public static NetworkCredential Credential = new NetworkCredential();

    public FtpWebRequestUtil()
    {
    }

    public FtpWebRequestUtil(string RemoteAddress, string RemotePath, string RemoteUser, string RemotePwd)
    {
        Credential.UserName = RemoteUser;
        Credential.Password = RemotePwd;
        RemoteHost = RemoteAddress;
        RemoteFtpPath = RemotePath;
    } 

    public string UploadFile(string localFilePath)
    {
        int startTime = Environment.TickCount;
       // Console.WriteLine("Uploading File " + localFilePath);
        try
        {
            FileInfo localFile = new FileInfo(localFilePath); //e.g.: c:\\Test.txt
            byte[] buf = new byte[2048];
            int iWork;
            string remoteFile = "ftp://" + RemoteHost + "/" + RemoteFtpPath + "/" + localFile.Name;

            FtpWebRequest req = (FtpWebRequest) FtpWebRequest.Create(remoteFile);
           // req.Proxy = 

            req.Credentials = Credential;


           // FtpWebRequest req = (FtpWe

            req.UseBinary = true;
            req.KeepAlive = true;
            req.Method = WebRequestMethods.Ftp.UploadFile;
            StreamWriter myStreamWriter = new StreamWriter(req.GetRequestStream());
            myStreamWriter.Write(new StreamReader("TestFiles\\" + localFile.Name).ReadToEnd());
            myStreamWriter.Close();
            FtpWebResponse myFtpWebResponse = (FtpWebResponse) req.GetResponse();
            Console.WriteLine("Upload File Complete, status: " + myFtpWebResponse.StatusDescription);

            myFtpWebResponse.Close();
            return "SUCCESS";
        }
        catch (Exception ex)
        {
            Console.WriteLine("There was an error connecting to the FTP Server.");
            Console.WriteLine(ex.Message);
            throw ex;
        }
        Console.WriteLine("Time taken for downloading file is " + (Environment.TickCount - startTime).ToString());
        return "FAILURE";
    }


    ************************                       *********************************
    FtpWebRequestUtil ftpClient = new FtpWebRequestUtil(FtpUrl, InputFolder, FtpUser, FtpPassword);
    try
    {
        Thread.Sleep(5000);
        ftpClient.UploadFile(UploadingFileName);
                }
        catch (Exception exception)
        {
            Assert.Fail(exception.Message);
        }
        finally
        {
            ftpClient = null;
        }
    }
}

Answer 1

req.Proxy = new WebProxy(); // initialize this FtpWebRequest property

Answer 2

It turns out that only the RETR , LIST , and NLST methods are supported by System.Net.FtpWebRequest when a HTTP proxy is configured and it doesn't matter that you are not setting a proxy in your code: if a HTTP proxy (not FTP proxy) is configured in the system proxy settings (in ie : Internet Options\\Connections\\LAN setting\\Proxy Server\\ Use a proxy server for your LAN), then you will get this error when trying to upload to the FTP server.

The workaround is use IE to change the system settings to switch off the use of the HTTP proxy. However if you have access to the affected code the solution is to set the Proxy property of the request to null, for example:

request.Proxy = null;

Answer 3

The exceptions itself is the answer - it is not supported. Probably you have some HTTP proxy that is preventing direct connection to FTP. According to MS documentation , if the specified proxy is an HTTP proxy, only the DownloadFile, ListDirectory, and ListDirectoryDetails commands are supported - so UploadFile is not.