Upload a file with encoding using FTP in C#

问题

The following code is good for uploading text files, but it fails to upload JPEG files (not completely - the file name is good but the image is corrupted):

private void up(string sourceFile, string targetFile)
{
    try
    {
        string ftpServerIP = ConfigurationManager.AppSettings["ftpIP"];
        string ftpUserID = ConfigurationManager.AppSettings["ftpUser"];
        string ftpPassword = ConfigurationManager.AppSettings["ftpPass"];

        //string ftpURI = "";
        string filename = "ftp://" + ftpServerIP + "//" + targetFile;
        FtpWebRequest ftpReq = (FtpWebRequest)WebRequest.Create(filename);
        ftpReq.Method = WebRequestMethods.Ftp.UploadFile;
        ftpReq.Credentials = new NetworkCredential(ftpUserID, ftpPassword);

        StreamReader stream = new StreamReader(sourceFile);
        Byte[] b = System.Text.Encoding.UTF8.GetBytes(stream.ReadToEnd());
        stream.Close();

        ftpReq.ContentLength = b.Length;
        Stream s = ftpReq.GetRequestStream();
        s.Write(b, 0, b.Length);
        s.Close();

        System.Net.FtpWebResponse ftpResp = (FtpWebResponse)ftpReq.GetResponse();
        MessageBox.Show(ftpResp.StatusDescription);
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.ToString());
    }
}

I have another solution that can upload a file:

private void Upload(string sourceFile, string targetFile)
{
    string ftpUserID;
    string ftpPassword;
    string ftpServerIP;
    ftpServerIP = ConfigurationManager.AppSettings["ftpIP"];
    ftpUserID = ConfigurationManager.AppSettings["ftpUser"];
    ftpPassword = ConfigurationManager.AppSettings["ftpPass"];
    FileInfo fileInf = new FileInfo(sourceFile);
    FtpWebRequest reqFTP;

    // Create FtpWebRequest object from the Uri provided
    reqFTP = (FtpWebRequest)(FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + "//" + targetFile)));

    // Provide the WebPermission Credintials
    reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);

    // Bypass default lan settings
    reqFTP.Proxy = null;

    // 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;

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

    // The buffer size is set to 2kb
    int buffLength = 2048;
    Byte[] buff;
    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
        long filesize = fs.Length;
        int i=0;
        contentLen = fs.Read(buff, 0, buffLength);

        // Till Stream content ends
        while (contentLen != 0)
        {
            Application.DoEvents();
            // Write Content from the file stream to the FTP Upload Stream
            strm.Write(buff, 0, contentLen);
            contentLen = fs.Read(buff, 0, buffLength);
            i = i + 1;
            //Double percentComp = (i * buffLength) * 100 / filesize;
            //ProgressBar1.Value = (int)percentComp;
        }

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

    catch (Exception ex)
    {
        MessageBox.Show(ex.Message, "Upload Error");
    }
}

But here I have the opposite problem - the picture is good, but the file name is corrupted.

I know it is because of the encoding, but I don't know how to make the bytes array have the desired encoding...

回答1:

Try this bit:

private static void up(string sourceFile, string targetFile)
{            
    try
    {
        string ftpServerIP = ConfigurationManager.AppSettings["ftpIP"];
        string ftpUserID = ConfigurationManager.AppSettings["ftpUser"];
        string ftpPassword = ConfigurationManager.AppSettings["ftpPass"];
        ////string ftpURI = "";
        string filename = "ftp://" + ftpServerIP + "//" + targetFile; 
        FtpWebRequest ftpReq = (FtpWebRequest)WebRequest.Create(filename);
        ftpReq.UseBinary = true;
        ftpReq.Method = WebRequestMethods.Ftp.UploadFile;
        ftpReq.Credentials = new NetworkCredential(ftpUserID, ftpPassword);

        byte[] b = File.ReadAllBytes(sourceFile);

        ftpReq.ContentLength = b.Length;
        using (Stream s = ftpReq.GetRequestStream())
        {
            s.Write(b, 0, b.Length);
        }

        FtpWebResponse ftpResp = (FtpWebResponse)ftpReq.GetResponse();

        if (ftpResp != null)
        {
            MessageBox.Show(ftpResp.StatusDescription);
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.ToString());
    }
}

回答2:

You should be using a Stream to read binary files, not a StreamReader. StreamReader is designed to read text files only.

回答3:

In your first code example, enable binary transfer: FtpWebRequest.UseBinary = true. Otherwise it will convert what it thinks are textual line endings between the various platform conventions (but are actually part of the image).

回答4:

Your second snippet does it the right way. It uses FileStream, not StreamReader. StreamReader is only suitable for text files.

回答5:

System.Text.Encoding.UTF8.GetBytes(stream.ReadToEnd());

Don't do this unless your stream's contents are text. Change your function to accept a boolean parameter "binary", and use the latter, working method if that flag is set.

回答6:

If you have this problem: The requested FTP command is not supported when using HTTP

you need set proxy in Null or Nothing.

ftpReq.Proxy = null;

You can see this blog.

http://mycodetrip.com/2008/10/29/fix-for-error-the-requested-ftp-command-is-not-supported-when-using-http-proxy_118/comment-page-1/#comment-2825

Thanks.

来源：https://stackoverflow.com/questions/3576436/upload-a-file-with-encoding-using-ftp-in-c-sharp