An FTP secure client library for C#

I'd suggest a check on the buffer length, something like below. (not tested)

private string readLine()
{
while (true)
{
if (useStream)
bytes = stream.Read(buffer, buffer.Length, 0);
else
bytes = clientSocket.Receive(buffer, buffer.Length, 0);

if (bytes == 0)
{
throw new Exception("Invalid buffer length");
}

mes += ASCII.GetString(buffer, 0, bytes);

if (bytes < buffer.Length)
{
break;
}
}

if (bytes == 0)
{
throw new Exception("Invalid buffer length");
}

This wont solve the issue:

char[] seperator = {'\n'};
string[] mess = mes.Split(seperator); // mes does not contain '\n'.

if(mes.Length > 2)
{
mes = mess[mess.Length-2]; //Exception: mes.length = 1, the split above didn't work. Confused | :confused:

}
else
{
mes = mess[0];
}

Unsure | :~

I am recieveing the error message: "The requested name is valid, but no data of the requested type was found" at the following line

FTP ftp = new FTP();

ftp.debug = true;
ftp.remoteHost = "ftp://.../";
ftp.remotePort = 990;
<big>ftp.loginWithoutUser();</big>  <-- Error here

string cmd = "AUTH SSL";
ftp.sendCommand(cmd);

When debugging through it the line in the FTP class that is throwing the excetioin is

IPEndPoint ep = new IPEndPoint(Dns.Resolve(remoteHost).AddressList[0], remotePort);

Not really sure what this may mean, any help would be great.

Thanks!

Devin Sackett

Hi,

The error (to me) suggests a DNS resolution problem, i.e. the DNS server was
contacted successfully, but was unable to provide any DNS records for the
host, perhaps because the DNS server is not authoritative for the domain
and no cache records exist, or perhaps an inherent problem with the DNS
server itself.

The name couldn't be resolved, because there is no entry in the responsible
DNS-server

If you can, try changing your DNS server to something else and run the tests
again

I recevied this as well because I put ftp:// before the server name in TargetFtpSource. Removing that solved the issue.

Is there a reason that no downloadSecure method exists?

Thx & regards

hi,
in this example i show only how to upload files on FTP secure,it's not a Complete FTP client but you can add it

Try the following code:

///
/// Download a file to the Assembly's local directory,
/// keeping the same file name.
///
///
public void downloadSecure(string remFileName)
{
    downloadSecure(remFileName, "", false);
}

///
/// Download a remote file to the Assembly's local directory,
/// keeping the same file name, and set the resume flag.
///
///
///
public void downloadSecure(string remFileName, Boolean resume)
{
    downloadSecure(remFileName, "", resume);
}

///
/// Download a remote file to a local file name which can include
/// a path. The local file name will be created or overwritten,
/// but the path must exist.
///
///
///
public void downloadSecure(string remFileName, string locFileName)
{
    downloadSecure(remFileName, locFileName, false);
}

///
/// Download a remote file to a local file name which can include
/// a path, and set the resume flag. The local file name will be
/// created or overwritten, but the path must exist.
///
///
///
///
public void downloadSecure(string remFileName, string locFileName, Boolean resume)
{
    if (!logined)
    {
        login();
    }

    setBinaryMode(true);

    sendCommand("PBSZ 0");
    sendCommand("PROT P");
    sendCommand("PASV");

    if (retValue != 227)
    {
        throw new IOException(reply.Substring(4));
    }

    Console.WriteLine("Downloading file " + remFileName + " from " + remoteHost + "/" + remotePath);

    if (locFileName.Equals(""))
    {
        locFileName = remFileName;
    }

    if (!File.Exists(locFileName))
    {
        Stream st = File.Create(locFileName);
        st.Close();
    }

    FileStream output;
    if (resume)
    {
        output = new FileStream(locFileName, FileMode.Open);
    }
    else
    {
        output = new FileStream(locFileName, FileMode.Truncate);
    }

    Socket cSocket = createDataSocket();
    isUpload = false;
    this.getSslDataStream(cSocket);

    long offset = 0;

    if (resume)
    {

        offset = output.Length;

        if (offset > 0)
        {
            sendCommand("REST " + offset);
            if (retValue != 350)
            {
                //throw new IOException(reply.Substring(4));
                //Some servers may not support resuming.
                offset = 0;
            }
        }

        if (offset > 0)
        {
            if (debug)
            {
                Console.WriteLine("seeking to " + offset);
            }
            long npos = output.Seek(offset, SeekOrigin.Begin);
            Console.WriteLine("new pos=" + npos);
        }
    }

    sendCommand("RETR " + remFileName);
    stream2.AuthenticateAsClient(
        remoteHost,
        null,
        System.Security.Authentication.SslProtocols.Ssl3 |
        System.Security.Authentication.SslProtocols.Tls,
        true);

    if (stream2.IsAuthenticated)
    {
        if (!(retValue == 125 || retValue == 150))
        {
            throw new IOException(reply.Substring(4));
        }

        while (true)
        {

            bytes = stream2.Read(buffer, 0, buffer.Length);
            output.Write(buffer, 0, bytes);

            if (bytes <= 0)
            {
                break;
            }
        }
        output.Close();
    }
    if (cSocket.Connected)
    {
        cSocket.Close();
    }

    Console.WriteLine("");

    readReply();

    if (!(retValue == 226 || retValue == 250))
    {
        throw new IOException(reply.Substring(4));
    }

}

And don't forget to read the other posts containing

this.getSslDataStream(cSocket);

Chears

One of FTPS servers I am using requires private key. In CuteFTP pro, there is a place for you to point to the location of the private key. I can't seem to find a way to do this in FTP secure client library?

it's a simple FTPS client library not a Complete FTP CLIENT like CuteFTP but i will see concerning "private key" in next version Wink | ;)

thank you for the idea.

Thanks alot for this article. I've been looking for something to do raw ftp in .net and this works great!

Been struggling with the ftpWebRequest today and this feels much more "controllable"

Quick (maybe studpid) question - why do you force passive mode on createDatasocket()?

Wouldn't it be better to set it up as an option to choose between active / passive mode?

Thanks again - great work

thank you for your message;

from http://www.nsftools.com/tips/RawFTP.htm#PASV[^] :

Tells the server to enter "passive mode". In passive mode, the server will wait for the client to establish a connection with it rather than attempting to connect to a client-specified port. The server will respond with the address of the port it is listening on, with a message like:
227 Entering Passive Mode (a1,a2,a3,a4,p1,p2)
where a1.a2.a3.a4 is the IP address and p1*256+p2 is the port number.

before sending a file (upload) , i must know the IP & Port number.

Hangs at the second call to AuthenticateAsClient() in GetSSLStream().

Everything connects, logs in, changes directory, etc., but once I call UploadSecure, that's where I get a hang.

First you must verify that the server accept SSL connection(990)! and you must send the command "AUTH SSL" before creating the SSL Stream like this:

string cmd = "AUTH SSL";
ftp.sendCommand(cmd);

//Create  SSL Stream
ftp.getSslStream();
ftp.setUseStream(true);

please to post the error message.

modified on Tuesday, December 16, 2008 4:18 AM

I am also having this issue. I Hang at the sslStream.AuthenticateAsClient( line after i call the uploadSecure method. any ideas?

Try sending the command before calling AuthenticateAsClient() on data connection as described here :

http://www.eggheadcafe.com/conversation.aspx?messageid=32558264&threadid=32544218[^]

brian64p was correct
"The FTP server wouldn't respond to authentication sent over
the data connection until the command that initiated
the data transfer was given.

The correct sequence (for those that come after) was PASV command,
open socket/stream, send command to request data, validate stream."

===============================
Here what I did to fix the problem AuthenticateAsClient()
I declare stream2 as SslStream (

private SslStream stream2;

I created a new function called getSslDataStream

public void getSslDataStream(Socket Csocket) {
   SslStream _sslStream = new SslStream(new NetworkStream(Csocket));
   stream2 = _sslStream;
}

Then in the uploadSecure function right after issuing the command STOR

public void uploadSecure(string fileName, Boolean resume) {
  ....
  Socket cSocket = createDataSocket();
  isUpload = true;
  this.getSslDataStream(cSocket);

  ....
  sendCommand("STOR " + Path.GetFileName(fileName)) // fileName is the relative file
  stream2.AuthenticateAsClient(remoteHost,
      null,
      System.Security.Authentication.SslProtocols.Ssl3 |
      System.Security.Authentication.SslProtocols.Tls,
      true);
  if (stream2.IsAuthenticated) {
     if (!(retValue == 125 || retValue == 150)) {
        throw new IOException(reply.Substring(4));
     }
     .....
     this.stream2.Close();
  }
  if (cSocket.Connected)
  {
     cSocket.Close();
  }
  readReply();
  ......
  }
}

Hopefully, this will save somebody 2 days of reading about FTP file over SSL & trying out the code in variety of ways.

modified on Friday, July 17, 2009 6:54 PM

Hi,
Can any one tell me if this code works for FTPS using Explicit SSL on port 21 instead of port 990? I'm using port 991.

My code hangs even after making all changes suggested by "sonnguyen79"

Any help is greatly appreciated!!

Thanks!

An FTP secure client library for C#

Introduction

SSL Stream?

Using the Code

1. Pre-Authenticate

2. Create SSL Stream

3. Upload File

Points of Interest

License

Comments and Discussions