0

I am using a .net console application written in C# to download certain files from an ftp server routinely, it used to work properly until there was a file with Hebrew characters, named something like that:

1234--אבג.jpeg

so I've tried to download the same file using both chrome and FileZilla - and encountered no problems, with neither plain nor URL encoded version of the filename.

My problem is how to download the same file with my C# application

I have tried:

  • to escape the name as URL-encoded, worked for chrome but not my APP
  • to convert the string to utf-8
  • both System.Net.WebRequest and HttpClient
  • finding and taking the name from response of directory listing and pasting into the request, hoping it will have the proper format.

here is my code :

 public static string attachmentToFile(string name, string filename)
    {
        try
        {
      
            string ftpConnection = ConfigurationManager.AppSettings["FtpServer"].ToString();
            string ftpUser = ConfigurationManager.AppSettings["FtpUser"].ToString();
            string ftpPassword = ConfigurationManager.AppSettings["FtpPassword"].ToString();
            string attachmentPath = ConfigurationManager.AppSettings["attachmentFolder"].ToString();

            Directory.CreateDirectory(attachmentPath);

            attachmentPath += '\\' + name + Path.GetExtension(filename);


            FtpWebRequest attachmentRequest = (FtpWebRequest)WebRequest.Create(
                new Uri(ftpConnection + "/files_directory/" + filename)
                );


            attachmentRequest.Credentials = new NetworkCredential(ftpUser, ftpPassword);
            attachmentRequest.Method = WebRequestMethods.Ftp.DownloadFile;

            FtpWebResponse response = (FtpWebResponse)attachmentRequest.GetResponse();
            var stream = response.GetResponseStream();
            FileStream saveStream = new FileStream(attachmentPath, FileMode.OpenOrCreate);
            //stream.Seek(0, SeekOrigin.Begin);
            stream.CopyTo(saveStream);
            saveStream.Close();
            return attachmentPath;
        }
        catch (Exception ex)
        {
            Logger.LogError(MethodBase.GetCurrentMethod(), ex, "failed downloading file from server: " + filename);
            return null;
        }
    }

the error is

The remote server returned an error: (550) File unavailable (e.g., file not found, no access).

while in Filezilla it's successful

Trace: CControlSocket::SendNextCommand()
Trace: CFtpLogonOpData::Send() in state 0
Status: Connecting to 11.111.111.11:1111...
Status: Connection established, waiting for welcome message...
Trace: CFtpControlSocket::OnReceive()
Response: 220---------- Welcome to Pure-FTPd [privsep] [TLS] ----------
Response: 220-You are user number 3 of 50 allowed.
Response: 220-Local time is now 09:16. Server port: 1111.
Response: 220-This is a private system - No anonymous login
Response: 220 You will be disconnected after 15 minutes of inactivity.
Trace: CFtpLogonOpData::ParseResponse() in state 1
Trace: CControlSocket::SendNextCommand()
Trace: CFtpLogonOpData::Send() in state 2
Command: AUTH TLS
Trace: CFtpControlSocket::OnReceive()
Response: 234 AUTH TLS OK.
Trace: CFtpLogonOpData::ParseResponse() in state 2
Status: Initializing TLS...
Trace: tls_layer_impl::client_handshake()
Trace: tls_layer_impl::continue_handshake()
Trace: tls_layer_impl::continue_handshake()
Trace: tls_layer_impl::continue_handshake()
Trace: tls_layer_impl::continue_handshake()
Trace: tls_layer_impl::continue_handshake()
Trace: TLS Handshake successful
Trace: Protocol: TLS1.2, Key exchange: ECDHE-RSA, Cipher: AES-256-GCM, MAC: AEAD
Trace: tls_layer_impl::verify_certificate()
Status: Verifying certificate...
Trace: CFtpControlSocket::SetAsyncRequestReply
Status: TLS connection established.
Trace: CControlSocket::SendNextCommand()
Trace: CFtpLogonOpData::Send() in state 6
Command: USER files@domain.co.il
Trace: CFtpControlSocket::OnReceive()
Trace: CFtpControlSocket::OnReceive()
Response: 331 User files@domain.co.il OK. Password required
Trace: CFtpLogonOpData::ParseResponse() in state 6
Trace: CControlSocket::SendNextCommand()
Trace: CFtpLogonOpData::Send() in state 6
Command: PASS ****************
Trace: CFtpControlSocket::OnReceive()
Response: 230 OK. Current restricted directory is /
Trace: CFtpLogonOpData::ParseResponse() in state 6
Trace: CControlSocket::SendNextCommand()
Trace: CFtpLogonOpData::Send() in state 10
Command: OPTS UTF8 ON
Trace: CFtpControlSocket::OnReceive()
Response: 504 Unknown command
Trace: CFtpLogonOpData::ParseResponse() in state 10
Trace: CControlSocket::SendNextCommand()
Trace: CFtpLogonOpData::Send() in state 11
Command: PBSZ 0
Trace: CFtpControlSocket::OnReceive()
Response: 200 PBSZ=0
Trace: CFtpLogonOpData::ParseResponse() in state 11
Trace: CControlSocket::SendNextCommand()
Trace: CFtpLogonOpData::Send() in state 12
Command: PROT P
Trace: CFtpControlSocket::OnReceive()
Response: 200 Data protection level set to "private"
Trace: CFtpLogonOpData::ParseResponse() in state 12
Status: Logged in
Trace: Measured latency of 16 ms
Trace: CFtpControlSocket::ResetOperation(0)
Trace: CControlSocket::ResetOperation(0)
Trace: CFtpLogonOpData::Reset(0) in state 15
Trace: CFtpControlSocket::FileTransfer()
Trace: CControlSocket::SendNextCommand()
Trace: CFtpFileTransferOpData::Send() in state 0
Status: Starting download of /files_directory/1234--אבג.jpeg
Trace: CFtpChangeDirOpData::Send() in state 0
Trace: CFtpChangeDirOpData::Send() in state 2
Command: CWD /files_directory
Trace: CFtpControlSocket::OnReceive()
Response: 250 OK. Current directory is /files_directory
Trace: CFtpChangeDirOpData::ParseResponse() in state 2
Trace: CFtpControlSocket::ResetOperation(0)
Trace: CControlSocket::ResetOperation(0)
Trace: CFtpChangeDirOpData::Reset(0) in state 2
Trace: CFtpFileTransferOpData::SubcommandResult(0) in state 1
Trace: CFtpControlSocket::SetAsyncRequestReply
Trace: CControlSocket::SendNextCommand()
Trace: CFtpFileTransferOpData::Send() in state 5
Trace: CFtpRawTransferOpData::Send() in state 1
Command: TYPE I
Trace: CFtpControlSocket::OnReceive()
Response: 200 TYPE is now 8-bit binary
Trace: CFtpRawTransferOpData::ParseResponse() in state 1
Trace: CControlSocket::SendNextCommand()
Trace: CFtpRawTransferOpData::Send() in state 2
Command: PASV
Trace: CFtpControlSocket::OnReceive()
Response: 227 Entering Passive Mode (11,111,111,11,111,11)
Trace: CFtpRawTransferOpData::ParseResponse() in state 2
Trace: CControlSocket::SendNextCommand()
Trace: CFtpRawTransferOpData::Send() in state 4
Trace: Binding data connection source IP to control connection source IP 10.0.0.13
Trace: tls_layer_impl::client_handshake()
Trace: Trying to resume existing TLS session.
Command: RETR 1234--אבג.jpeg
Trace: tls_layer_impl::continue_handshake()
Trace: CFtpControlSocket::OnReceive()
Response: 150-Accepted data connection
Response: 150 206.6 kbytes to download
Trace: CFtpRawTransferOpData::ParseResponse() in state 4
Trace: CControlSocket::SendNextCommand()
Trace: CFtpRawTransferOpData::Send() in state 5
Trace: tls_layer_impl::continue_handshake()
Trace: TLS Handshake successful
Trace: TLS Session resumed
Trace: Protocol: TLS1.2, Key exchange: ECDHE-RSA, Cipher: AES-256-GCM, MAC: AEAD
Trace: tls_layer_impl::verify_certificate()
Trace: CTransferSocket::OnConnect
Trace: CFtpControlSocket::OnReceive()
Response: 226-File successfully transferred
Trace: CFtpControlSocket::OnReceive()
Response: 226 0.120 seconds (measured here), 1.68 Mbytes per second
Trace: CFtpRawTransferOpData::ParseResponse() in state 5
Trace: CControlSocket::SendNextCommand()
Trace: CFtpRawTransferOpData::Send() in state 8
Trace: CTransferSocket::TransferEnd(1)
Trace: tls_layer_impl::shutdown()
Trace: tls_layer_impl::continue_shutdown()
Trace: CFtpControlSocket::TransferEnd()
Trace: CFtpControlSocket::ResetOperation(0)
Trace: CControlSocket::ResetOperation(0)
Trace: CFtpRawTransferOpData::Reset(0) in state 8
Trace: CFtpFileTransferOpData::SubcommandResult(0) in state 7
Trace: CFtpControlSocket::ResetOperation(0)
Trace: CControlSocket::ResetOperation(0)
Trace: CFtpFileTransferOpData::Reset(0) in state 7
Status: File transfer successful, transferred 211,556 bytes in 1 second
Status: Disconnected from server

network.log

System.Net Information: 0 : [14564] FtpWebRequest#54024015::.ctor(ftp://files%40domain.co.il@11.111.111.11:1111/files_directory/22222222-IMG-222222-222222.jpg)
System.Net Information: 0 : [14564] FtpWebRequest#54024015::GetResponse(Method=RETR.)
System.Net Information: 0 : [14564] Current OS installation type is 'Client'.
System.Net Information: 0 : [14564] RAS supported: True
System.Net Information: 0 : [14564] FtpControlStream#13869071 - Created connection from 10.0.0.13:11111 to 11.111.111.11:1111.
System.Net Information: 0 : [14564] Associating FtpWebRequest#54024015 with FtpControlStream#13869071
System.Net Information: 0 : [14564] FtpControlStream#13869071 - Received response [220---------- Welcome to Pure-FTPd [privsep] [TLS] ----------
220-You are user number 3 of 50 allowed.
220-Local time is now 09:44. Server port: 1111.
220-This is a private system - No anonymous login
220 You will be disconnected after 15 minutes of inactivity.]

....

150 119.1 kbytes to download]
System.Net Information: 0 : [14564] FtpControlStream#13869071 - Received response [226-File successfully transferred
226 0.052 seconds (measured here), 2.24 Mbytes per second]

....

150 4312.7 kbytes to download]
System.Net Information: 0 : [14564] FtpControlStream#13869071 - Received response [226-File successfully transferred
226 1.874 seconds (measured here), 2.25 Mbytes per second]

....

150 1974.2 kbytes to download]
System.Net Information: 0 : [14564] FtpControlStream#13869071 - Received response [226-File successfully transferred
226 0.884 seconds (measured here), 2.18 Mbytes per second]
System.Net Information: 0 : [14564] FtpWebRequest#49652976::(Releasing FTP connection#13869071.)
System.Net Information: 0 : [14564] FtpWebRequest#44223604::.ctor(ftp://files%40domain.co.il@11.111.111.11:1111/files_directory/11111111-1111111111.jpg)
System.Net Information: 0 : [14564] FtpWebRequest#44223604::GetResponse(Method=RETR.)
System.Net Information: 0 : [14564] Associating FtpWebRequest#44223604 with FtpControlStream#13869071
System.Net Information: 0 : [14564] FtpControlStream#13869071 - Sending command [PASV]
System.Net Information: 0 : [14564] FtpControlStream#13869071 - Received response [227 Entering Passive Mode (11,111,111,11,111,111)]
System.Net Information: 0 : [14564] FtpControlStream#13869071 - Sending command [RETR files_directory/11111111-1111111111.jpg]
System.Net Information: 0 : [14564] FtpControlStream#13869071 - Received response [150-Accepted data connection
150 1953.3 kbytes to download]
System.Net Information: 0 : [14564] FtpControlStream#13869071 - Received response [226-File successfully transferred
226 0.929 seconds (measured here), 2.05 Mbytes per second]
System.Net Information: 0 : [14564] FtpWebRequest#44223604::(Releasing FTP connection#13869071.)
System.Net Information: 0 : [14564] FtpWebRequest#62468121::.ctor(ftp://files%40domain.co.il@11.111.111.11:1111/files_directory/1234--אבג.jpeg)
System.Net Information: 0 : [14564] FtpWebRequest#62468121::GetResponse(Method=RETR.)
System.Net Information: 0 : [14564] Associating FtpWebRequest#62468121 with FtpControlStream#13869071
System.Net Information: 0 : [14564] FtpControlStream#13869071 - Sending command [PASV]
System.Net Information: 0 : [14564] FtpControlStream#13869071 - Received response [227 Entering Passive Mode (11,111,111,11,111,111)]
System.Net Information: 0 : [14564] FtpControlStream#13869071 - Sending command [RETR files_directory/1234--אבג.jpeg]
System.Net Information: 0 : [14564] FtpControlStream#13869071 - Received response [550 Can't open files_directory/1234--אבג.jpeg: No such file or directory]
System.Net Information: 0 : [14564] FtpWebRequest#62468121::(Releasing FTP connection#13869071.)
System.Net Error: 0 : [14564] Exception in FtpWebRequest#62468121::GetResponse - The remote server returned an error: (550) File unavailable (e.g., file not found, no access)..
at System.Net.FtpWebRequest.SyncRequestCallback(Object obj)
at System.Net.FtpWebRequest.RequestCallback(Object obj)
at System.Net.CommandStream.Dispose(Boolean disposing)
at System.IO.Stream.Close()
at System.IO.Stream.Dispose()
at System.Net.ConnectionPool.Destroy(PooledStream pooledStream)
at System.Net.ConnectionPool.PutConnection(PooledStream pooledStream, Object owningObject, Int32 creationTimeout, Boolean canReuse)
at System.Net.FtpWebRequest.FinishRequestStage(RequestStage stage)
at System.Net.FtpWebRequest.GetResponse()

Michael Razgoner
  • 124
  • 1
  • 8
  • FTP has a "usebinary" property. Normal FTP mode is text which will filter characters. If you do not want any filtering than use the binary mode. – jdweng Oct 17 '20 at 12:54
  • 2
    And what's the problem you have? Any error? Problems with user input? File not found? be more specific – Gusman Oct 17 '20 at 12:55
  • As @Gusman said, be more specific about the issue you're seeing. You probably need to `HttpUtility.UrlEncode` the filename. – jeroenh Oct 17 '20 at 13:10
  • Show us FileZilla verbose log file as well as [`FtpWebRequest` log file](https://stackoverflow.com/q/9664650/850848). – Martin Prikryl Oct 17 '20 at 16:57
  • @jdweng The question is about file names, not file contents. Binary/Text mode is irrelevant here. – Martin Prikryl Oct 17 '20 at 16:57
  • @ Martin Prikryl I have edited in both logs you mentioned, still cannot find what FileZilla and chrome do right that I do wrong, except for "Command: OPTS UTF8 ON" but I don't know how to reproduce it in C# after searching – Michael Razgoner Oct 18 '20 at 13:49

1 Answers1

0

although I didn't find the exact reason for the error, after printing FileZilla verbose log and FtpWebRequest as suggested in the comments and reading some more I have read that it's hard to change certain configurations using System.Net.WebRequest and HttpClient, so I used a 3d party library (FluentFTP) there were many configurations available but I didn't need to do anything in my case and the problem was solved by the default configurations.

Michael Razgoner
  • 124
  • 1
  • 8