16.2 Net::FTP (Perl in a Nutshell)

16.2 Net::FTP

Net::FTP is used to transfer files from remote hosts. Using Net::FTP, you can write simple FTP clients that transfer files from remote servers based on information passed on the command line or from hard-coded variables. Here is an example of a client that connects to a remote FTP server and gets a file from the server:

#!/usr/local/bin/perl -w

use Net::FTP;

$hostname = 'remotehost.com';
$username = 'anonymous';
$password = 'myname@mydomain.com';

# Hardcode the directory and filename to get
$home = '/pub';
$filename = 'TESTFILE';

# Open the connection to the host
$ftp = Net::FTP->new($hostname);         # construct object
$ftp->login($username, $password);       # log in

$ftp->cwd($home),"\n";                   # change directory
print $ftp->ls($home),"\n";        

# Now get the file and leave
$ftp->get($filename); 
$ftp->quit;

FTP clients have also been integrated with most World Wide Web browsers, using ftp:// in place of http://. When the URL points to a directory, the browser displays a listing of the directory, where each filename is a link to that file. When the URL points directly to a file, the remote file is downloaded.

Here's an example that uses Net::FTP to list files from a remote FTP server on a web page, with a link from each file to the URL of the file on the remote site:

#!/usr/local/bin/perl -w

use Net::FTP;

$hostname = 'remotehost.com';           # ftp host
$username = 'anonymous';                # username
$password = 'myname@mydomain.com';      # password
$home = '/pub';

$ftp = Net::FTP->new($hostname);        # Net::FTP constructor
$ftp->login($username, $password);      # log in w/username and password

$pwd = $ftp->pwd;                       # get current directory

# Now, output HTML page.
print <<HTML;
Content-type: text/html
<HTML>
  
  <HEAD>
    <TITLE>Download Files</TITLE>
  </HEAD>
  <BODY>
      
      <B>Current working directory:</B> $pwd<BR>
      Files to download: <P>
HTML
  
    @entries = $ftp->ls($home);       # slurp all entries into an array
    foreach (@entries) { # now, output links for all files in the ftp area
                         # as links
        print "<INPUT TYPE=hidden NAME=\"files\" VALUE=\"$_\">\n";
        print "<A HREF=\"ftp://$hostname$_\">",
        "<IMG SRC=\"http://www/icons/f.gif\" border=0>\n";
        print " $_</A><BR>\n";
    }
    print <<HTML;
  </BODY>
</HTML>
HTML
$ftp->quit;             # end FTP session

The Net::FTP module implements a subset (as shown earlier in this chapter) of the FTP protocol as defined in RFC 959. In addition to providing the methods shown below, the module inherits from Net::Cmd. Some of the Net::FTP methods return an object derived from the dataconn class (which is in turn derived from the IO::Socket::INET class), as noted in the entries for those methods.

The following methods are defined by Net::FTP: