CODEWITHSUNDEEP
javasshftpsftpjsch
Bipin Karkee
Bipin Karkee

Reputation: 43

How to return the system type in an SFTP?

FTP and SFTP are different, but I wanted to know is there a equivalent to a "SYST" command in FTP for SFTP. If I have an SFTP connection using JSch and I wanted to return the system type, how would I do that? I am converting FTP connection to SFTP. If there is no way to do with an SFTP, is there a workaround for it?

public String getSystemType()
        throws IOException, FtpException
{
    if(out == null)
        return null;
    acquire();    // Acquire the object

    try {
        ftpCommand("SYST");             //sends command to FTP to retrieve the system type.
        if(!reply.substring(0, 3).equals("215"))
            throw new FtpException(reply);
    } finally { 
        release();    // Release the object
    }

    return reply.substring(4);
}

I need this "system type" to parse the result of information of a file or directory from a location. It could be a Windows server or a UNIX server. Depending on that I need to parse it to retrieve

1) Name
* 2) Permission ..not available in MSDOS format list
* 3) Type
* 4) Owner ..not available in MSDOS format list
* 5) Group ..not available in MSDOS format list
* 6) Size

* Parse a UNIX format list. With skipping number of lines.
     * The columns of a typical UNIX format list is like:
     * drwxr-xr-x   6 appli    appli        1024 May 17 20:33 java
     * -rw-------   1 appli    appli        1005 May  1 21:21 mp3list
     * drwxr-xr-x   5 appli    appli        1024 May 17 16:56 perl
     * drwxr-xr-x   6 appli    appli        1024 Apr 30 23:18 public_html

// Some UNIX format list doesn't contain the column for group like this:
            // -rw-r--r--   1 daemon         0 Dec  7 10:15 .notar
            // -r--r--r--   1 daemon       828 Mar 30  1995 HOW_TO_SUBMIT
            // -r--r--r--   1 daemon       627 Mar 30  1995 README
            // -r--r--r--   1 daemon       876 Mar 30  1995 WELCOME
            // drwxr-xr-x   2 ftp          512 Oct 13  1999 bin

Upvotes: 1

Views: 925

Answers (2)

Martin Prikryl
Martin Prikryl

Reputation: 202692

You can use SSH version string.

It is like:

  • SSH-2.0-OpenSSH_5.3
  • SSH-2.0-7.34 FlowSsh: Bitvise SSH Server (WinSSHD) 7.34
  • SSH-2.0-1.36_sshlib GlobalSCAPE
  • SSH-2.0-mod_sftp/0.9.8

In JSch you can retrieve it by using Session.getServerVersion.

SFTP itself provides information about the remote system only using an optional extension "vendor-id", which is rarely supported. It's definitely not supported by JSch itself and neither by the most widespread SFTP server implementation, the OpenSSH.

Though note that with SFTP, you typically do not need to parse the directory listing. In SFTP most of the listing data come in a form of binary structure, not a textual listing like with FTP.

Upvotes: 1

Kenster
Kenster

Reputation: 25458

The most widely deployed SFTP server is the server included with OpenSSH. It implements version 3 draft 2. Jsch also implements that version of SFTP.

The FTP SYST command returns a string describing the server's system type. Sftp version 3 draft 2 doesn't implement anything like the FTP SYST command that I can see. There's no command that returns the server's operating system or a set of capabilities.

Without knowing why you need the information, it's impossible to say how to work around this.

Upvotes: 1

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