FTP exception 501 “pathname” more than 8 characters

Question

I am trying to access a file via a URI using the FTP protocol. For obvious security reasons I had to make some changes but this is where the problems seem to be coming from.

My URI is as follows: ftp://user:pasword@host.net/u/Bigpathname/XYZ/ABC/BigPathname/bigpathname/xyz/abc/MY_LOG.LOG

And I see this exception:

sun.net.ftp.FtpProtocolException: CWD Bigpathname:501 A qualifier in "Bigpathname" is more than 8 characters

This is really confusing as I can access the file from a Windows 7 command line with the CD command just fine. Both one directory at a time and as a full path.

I found one article mentioning that MVS file names must be 8 or fewer characters but this does not explain how I can get to these same files from my command line! They do exist there is data there that I can download manual but I can not get there via a URI in Java.

PS I use .toURL().openStream() to get files on my local machine just fine, it only fails when I try to get them from my server.

EDIT October 1st

I am able to access files on the MVS host using FileZilla and the basic FTP client from the Windows 7 command line - but I still cannot get them from a URI/URL. I downloaded a very basic Java built FTP client and tried accessing the same file in my program from there and the path works but because my file name has a dot in it "MY_LOG.LOG" I am getting File does not exist 501 Invalid data set name "MY_LOG.LOG". Use MVS Dsname conventions. I am utterly perplexed by this...

EDIT Ocotober 1st afternoon :)

OK I finally got it to work with a FTP client in my Java code - but I still want to use the URL class as I have logs on both local and remote machines. Is there a way to encode a URL string so that it can retrieve a file from a remote machine with the FTP protocol? I am not sure how it works in the Java URL class but in the FTP client I had to use the CWD and then the RETR command.

If I can do this then I have one solution for getting all my logs, otherwise I will have to detect if it is a file or ftp URL and then behave differently. Not the end of the world but not what I want...

The code that tries to get the file with just a URL is as follows: (sysc is a valid host)

void testFTP()
{
   String ftp = "ftp://user:pword@sysc/u/Xxxxxxxxxx/ICS/YT7/XxxxxXxxxxxxx/xxxxxxxxx/logs/xxxxxxxx/XX_YT.LOG";

   try
   {
       URI uri = new URI(ftp);
       URL ftpFile = uri.toURL();

       BufferedReader in = new BufferedReader(new InputStreamReader(ftpFile.openStream()));

       String inputLine;
       while ((inputLine = in.readLine()) != null)
        System.out.println(inputLine);

       in.close();
    }
    catch(Exception e)
    {
       e.printStackTrace();
    }
}

Answer 1

In this case I think the problem is also Server Related, It all works fine for me with Filezilla Server except when the filename length(including directories) exceeds 255 chars but if you want to use the URL class with another FTP you must override or implement your own URLStreamHandlerFactory.

       URL.setURLStreamHandlerFactory(...);

I haven't found any for my favorite java FTP Client witch is Apache one so I have developed one but may need a few touch ups.

package net.custom.streamhandler.apacheftp;

import java.io.IOException;
import java.io.InputStream;
import java.net.SocketException;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLStreamHandler;
import java.net.URLStreamHandlerFactory;

import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPReply;


public class ApacheURLStreamHandlerFactory implements URLStreamHandlerFactory { 
    public URLStreamHandler createURLStreamHandler(String protocol) { 
        //this will only override the chosen protocol  
        if ( protocol.equalsIgnoreCase("ftp") ) 
            return new CustomHandler(); 
        else 
            return null;
    } 
}
class CustomHandler extends URLStreamHandler { 
    protected URLConnection openConnection(URL url) 
       throws IOException { 
        return new CustomURLConnection(url); 
    } 
} 

class CustomURLConnection extends URLConnection { 

    int reply;
    FTPClient ftp = new FTPClient();
    InputStream in;
    static int defaultPort = 21; 
    static String defaultPath = "/"; 

    CustomURLConnection ( URL url) 
        throws IOException { 
        super( url ); 
    } 
    synchronized public void connect() throws IOException {  
            try {
                int port; 
                if ((port = url.getPort()) == -1 ) 
                    port = defaultPort; 

                ftp.connect(url.getHost(), port);
                String login = "anonymous";
                String password = "";
                if(url.getAuthority().indexOf(':')>-1 && 
                        url.getAuthority().indexOf('@')>-1){
                            String []auxArray = url.getAuthority().replaceAll("@", ":").split(":");
                            login = auxArray[0];
                            password = auxArray[1];
                }               

                ftp.login(login, password);             

                reply = ftp.getReplyCode();
                if (FTPReply.isPositiveCompletion(reply)) {
                    System.out.println("Connected Apache Success");
                } else {
                    System.out.println("Connection Apache Failed");
                    ftp.disconnect();
                }
                in = ftp.retrieveFileStream(url.getFile());

            } catch (SocketException ex) {
                ex.printStackTrace();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        connected = true;        

    } 
    synchronized public InputStream getInputStream() 
       throws IOException { 
        if (!connected) 
            connect(); 
        return ( in );  
    }  
} 

*Keep in mind that you can implement new ways to handle different protocols for the java.net.URL this way.

Your code...

    ...
{
   String ftp = "ftp://user:pword@sysc/u/Xxxxxxxxxx/ICS/YT7/XxxxxXxxxxxxx/xxxxxxxxx/logs/xxxxxxxx/XX_YT.LOG";    
   try
   {
       URL.setURLStreamHandlerFactory(new ApacheURLStreamHandlerFactory()); 
    ...

G'Bye

**(To err is human, to forgive is divine)

Answer 2

Try using the short name for the path. Something like /U/BIGPAT~1/XYZ/ABC/BIGPAT~1/BIGPAT~1/XYZ/ABC/MY_LOG.LOG

You can find the short name for any directory longer than 8 characters with dir /x.

Answer 3

FTP clients are notoriously difficult to write given the variation of (and bugs in) server implementations.

I'm betting that MVS is not completely supported by sun.net.ftp.FtpClient, which is the class used under the hood when you call URL.openStream on an FTP URL.

The Apache Commons Net library should support MVS, but it sounds like you already found a working client.

Answer 4

Have you considered using an RMI for transporting the files that way you can give a direct path to the file as a parameter without the use of ftp then have the file sent back in a byte array.