Net::FTP(3pm) Perl Programmers Reference Guide Net::FTP(3pm)
NAME
Net::FTP - FTP Client class
SYNOPSIS
use Net::FTP;
$ftp = Net::FTP->new("some.host.name", Debug => 0)
or die "Cannot connect to some.host.name: $@";
$ftp->login("anonymous",'-anonymous@')
or die "Cannot login ", $ftp->message;
$ftp->cwd("/pub")
or die "Cannot change working directory ", $ftp->message;
$ftp->get("that.file")
or die "get failed ", $ftp->message;
$ftp->quit;
DESCRIPTION
"Net::FTP" is a class implementing a simple FTP client in Perl as
described in RFC959. It provides wrappers for the commonly used subset
of the RFC959 commands. If IO::Socket::IP or IO::Socket::INET6 is
installed it also provides support for IPv6 as defined in RFC2428. And
with IO::Socket::SSL installed it provides support for implicit FTPS
and explicit FTPS as defined in RFC4217.
The Net::FTP class is a subclass of Net::Cmd and (depending on
avaibility) of IO::Socket::IP, IO::Socket::INET6 or IO::Socket::INET.
Overview
FTP stands for File Transfer Protocol. It is a way of transferring
files between networked machines. The protocol defines a client (whose
commands are provided by this module) and a server (not implemented in
this module). Communication is always initiated by the client, and the
server responds with a message and a status code (and sometimes with
data).
The FTP protocol allows files to be sent to or fetched from the server.
Each transfer involves a local file (on the client) and a remote file
(on the server). In this module, the same file name will be used for
both local and remote if only one is specified. This means that
transferring remote file "/path/to/file" will try to put that file in
"/path/to/file" locally, unless you specify a local file name.
The protocol also defines several standard translations which the file
can undergo during transfer. These are ASCII, EBCDIC, binary, and
byte. ASCII is the default type, and indicates that the sender of
files will translate the ends of lines to a standard representation
which the receiver will then translate back into their local
representation. EBCDIC indicates the file being transferred is in
EBCDIC format. Binary (also known as image) format sends the data as a
contiguous bit stream. Byte format transfers the data as bytes, the
values of which remain the same regardless of differences in byte size
between the two machines (in theory - in practice you should only use
this if you really know what you're doing). This class does not
support the EBCDIC or byte formats, and will default to binary instead
if they are attempted.
Class Methods
"new([$host][, %options])"
This is the constructor for a new Net::FTP object. $host is the
name of the remote host to which an FTP connection is required.
$host is optional. If $host is not given then it may instead be
passed as the "Host" option described below.
%options are passed in a hash like fashion, using key and value
pairs. Possible options are:
Host - FTP host to connect to. It may be a single scalar, as
defined for the "PeerAddr" option in IO::Socket::INET, or a
reference to an array with hosts to try in turn. The "host" method
will return the value which was used to connect to the host.
Firewall - The name of a machine which acts as an FTP firewall.
This can be overridden by an environment variable "FTP_FIREWALL".
If specified, and the given host cannot be directly connected to,
then the connection is made to the firewall machine and the string
@hostname is appended to the login identifier. This kind of setup
is also referred to as an ftp proxy.
FirewallType - The type of firewall running on the machine
indicated by Firewall. This can be overridden by an environment
variable "FTP_FIREWALL_TYPE". For a list of permissible types, see
the description of ftp_firewall_type in Net::Config.
BlockSize - This is the block size that Net::FTP will use when
doing transfers. (defaults to 10240)
Port - The port number to connect to on the remote machine for the
FTP connection
SSL - If the connection should be done from start with SSL,
contrary to later upgrade with "starttls".
SSL_* - SSL arguments which will be applied when upgrading the
control or data connection to SSL. You can use SSL arguments as
documented in IO::Socket::SSL, but it will usually use the right
arguments already.
Timeout - Set a timeout value in seconds (defaults to 120)
Debug - debug level (see the debug method in Net::Cmd)
Passive - If set to a non-zero value then all data transfers will
be done using passive mode. If set to zero then data transfers will
be done using active mode. If the machine is connected to the
Internet directly, both passive and active mode should work equally
well. Behind most firewall and NAT configurations passive mode has
a better chance of working. However, in some rare firewall
configurations, active mode actually works when passive mode
doesn't. Some really old FTP servers might not implement passive
transfers. If not specified, then the transfer mode is set by the
environment variable "FTP_PASSIVE" or if that one is not set by the
settings done by the libnetcfg utility. If none of these apply
then passive mode is used.
Hash - If given a reference to a file handle (e.g., "\*STDERR"),
print hash marks (#) on that filehandle every 1024 bytes. This
simply invokes the hash() method for you, so that hash marks are
displayed for all transfers. You can, of course, call hash()
explicitly whenever you'd like.
LocalAddr - Local address to use for all socket connections. This
argument will be passed to the super class, i.e. IO::Socket::INET
or IO::Socket::IP.
Domain - Domain to use, i.e. AF_INET or AF_INET6. This argument
will be passed to the IO::Socket super class. This can be used to
enforce IPv4 even with IO::Socket::IP which would default to IPv6.
Family is accepted as alternative name for Domain.
If the constructor fails undef will be returned and an error
message will be in $@
Object Methods
Unless otherwise stated all methods return either a true or false
value, with true meaning that the operation was a success. When a
method states that it returns a value, failure will be returned as
undef or an empty list.
"Net::FTP" inherits from "Net::Cmd" so methods defined in "Net::Cmd"
may be used to send commands to the remote FTP server in addition to
the methods documented here.
"login([$login[, $password[, $account]]])"
Log into the remote FTP server with the given login information. If
no arguments are given then the "Net::FTP" uses the "Net::Netrc"
package to lookup the login information for the connected host. If
no information is found then a login of anonymous is used. If no
password is given and the login is anonymous then anonymous@ will
be used for password.
If the connection is via a firewall then the "authorize" method
will be called with no arguments.
starttls()
Upgrade existing plain connection to SSL. The SSL arguments have
to be given in "new" already because they are needed for data
connections too.
stoptls()
Downgrade existing SSL connection back to plain. This is needed to
work with some FTP helpers at firewalls, which need to see the PORT
and PASV commands and responses to dynamically open the necessary
ports. In this case "starttls" is usually only done to protect the
authorization.
prot($level)
Set what type of data channel protection the client and server will
be using. Only $levels "C" (clear) and "P" (private) are
supported.
host()
Returns the value used by the constructor, and passed to the
IO::Socket super class to connect to the host.
account($acct)
Set a string identifying the user's account.
"authorize([$auth[, $resp]])"
This is a protocol used by some firewall ftp proxies. It is used to
authorise the user to send data out. If both arguments are not
specified then "authorize" uses "Net::Netrc" to do a lookup.
site($args)
Send a SITE command to the remote server and wait for a response.
Returns most significant digit of the response code.
ascii()
Transfer file in ASCII. CRLF translation will be done if required
binary()
Transfer file in binary mode. No transformation will be done.
Hint: If both server and client machines use the same line ending
for text files, then it will be faster to transfer all files in
binary mode.
type([$type])
Set or get if files will be transferred in ASCII or binary mode.
"rename($oldname, $newname)"
Rename a file on the remote FTP server from $oldname to $newname.
This is done by sending the RNFR and RNTO commands.
delete($filename)
Send a request to the server to delete $filename.
cwd([$dir])
Attempt to change directory to the directory given in $dir. If
$dir is "..", the FTP "CDUP" command is used to attempt to move up
one directory. If no directory is given then an attempt is made to
change the directory to the root directory.
cdup()
Change directory to the parent of the current directory.
passive([$passive])
Set or get if data connections will be initiated in passive mode.
pwd()
Returns the full pathname of the current directory.
restart($where)
Set the byte offset at which to begin the next data transfer.
Net::FTP simply records this value and uses it when during the next
data transfer. For this reason this method will not return an
error, but setting it may cause a subsequent data transfer to fail.
"rmdir($dir[, $recurse])"
Remove the directory with the name $dir. If $recurse is true then
"rmdir" will attempt to delete everything inside the directory.
"mkdir($dir[, $recurse])"
Create a new directory with the name $dir. If $recurse is true then
"mkdir" will attempt to create all the directories in the given
path.
Returns the full pathname to the new directory.
"alloc($size[, $record_size])"
The alloc command allows you to give the ftp server a hint about
the size of the file about to be transferred using the ALLO ftp
command. Some storage systems use this to make intelligent
decisions about how to store the file. The $size argument
represents the size of the file in bytes. The $record_size argument
indicates a maximum record or page size for files sent with a
record or page structure.
The size of the file will be determined, and sent to the server
automatically for normal files so that this method need only be
called if you are transferring data from a socket, named pipe, or
other stream not associated with a normal file.
ls([$dir])
Get a directory listing of $dir, or the current directory.
In an array context, returns a list of lines returned from the
server. In a scalar context, returns a reference to a list.
dir([$dir])
Get a directory listing of $dir, or the current directory in long
format.
In an array context, returns a list of lines returned from the
server. In a scalar context, returns a reference to a list.
"get($remote_file[, $local_file[, $where]])"
Get $remote_file from the server and store locally. $local_file may
be a filename or a filehandle. If not specified, the file will be
stored in the current directory with the same leafname as the
remote file.
If $where is given then the first $where bytes of the file will not
be transferred, and the remaining bytes will be appended to the
local file if it already exists.
Returns $local_file, or the generated local file name if
$local_file is not given. If an error was encountered undef is
returned.
"put($local_file[, $remote_file])"
Put a file on the remote server. $local_file may be a name or a
filehandle. If $local_file is a filehandle then $remote_file must
be specified. If $remote_file is not specified then the file will
be stored in the current directory with the same leafname as
$local_file.
Returns $remote_file, or the generated remote filename if
$remote_file is not given.
NOTE: If for some reason the transfer does not complete and an
error is returned then the contents that had been transferred will
not be remove automatically.
"put_unique($local_file[, $remote_file])"
Same as put but uses the "STOU" command.
Returns the name of the file on the server.
"append($local_file[, $remote_file])"
Same as put but appends to the file on the remote server.
Returns $remote_file, or the generated remote filename if
$remote_file is not given.
unique_name()
Returns the name of the last file stored on the server using the
"STOU" command.
mdtm($file)
Returns the modification time of the given file
size($file)
Returns the size in bytes for the given file as stored on the
remote server.
NOTE: The size reported is the size of the stored file on the
remote server. If the file is subsequently transferred from the
server in ASCII mode and the remote server and local machine have
different ideas about "End Of Line" then the size of file on the
local machine after transfer may be different.
supported($cmd)
Returns TRUE if the remote server supports the given command.
"hash([$filehandle_glob_ref[, $bytes_per_hash_mark]])"
Called without parameters, or with the first argument false, hash
marks are suppressed. If the first argument is true but not a
reference to a file handle glob, then \*STDERR is used. The second
argument is the number of bytes per hash mark printed, and defaults
to 1024. In all cases the return value is a reference to an array
of two: the filehandle glob reference and the bytes per hash mark.
feature($name)
Determine if the server supports the specified feature. The return
value is a list of lines the server responded with to describe the
options that it supports for the given feature. If the feature is
unsupported then the empty list is returned.
if ($ftp->feature( 'MDTM' )) {
# Do something
}
if (grep { /\bTLS\b/ } $ftp->feature('AUTH')) {
# Server supports TLS
}
The following methods can return different results depending on how
they are called. If the user explicitly calls either of the "pasv" or
"port" methods then these methods will return a true or false value. If
the user does not call either of these methods then the result will be
a reference to a "Net::FTP::dataconn" based object.
nlst([$dir])
Send an "NLST" command to the server, with an optional parameter.
list([$dir])
Same as "nlst" but using the "LIST" command
retr($file)
Begin the retrieval of a file called $file from the remote server.
stor($file)
Tell the server that you wish to store a file. $file is the name of
the new file that should be created.
stou($file)
Same as "stor" but using the "STOU" command. The name of the unique
file which was created on the server will be available via the
"unique_name" method after the data connection has been closed.
appe($file)
Tell the server that we want to append some data to the end of a
file called $file. If this file does not exist then create it.
If for some reason you want to have complete control over the data
connection, this includes generating it and calling the "response"
method when required, then the user can use these methods to do so.
However calling these methods only affects the use of the methods above
that can return a data connection. They have no effect on methods
"get", "put", "put_unique" and those that do not require data
connections.
port([$port])
eprt([$port])
Send a "PORT" (IPv4) or "EPRT" (IPv6) command to the server. If
$port is specified then it is sent to the server. If not, then a
listen socket is created and the correct information sent to the
server.
pasv()
epsv()
Tell the server to go into passive mode ("pasv" for IPv4, "epsv"
for IPv6). Returns the text that represents the port on which the
server is listening, this text is in a suitable form to send to
another ftp server using the "port" or "eprt" method.
The following methods can be used to transfer files between two remote
servers, providing that these two servers can connect directly to each
other.
"pasv_xfer($src_file, $dest_server[, $dest_file ])"
This method will do a file transfer between two remote ftp servers.
If $dest_file is omitted then the leaf name of $src_file will be
used.
"pasv_xfer_unique($src_file, $dest_server[, $dest_file ])"
Like "pasv_xfer" but the file is stored on the remote server using
the STOU command.
pasv_wait($non_pasv_server)
This method can be used to wait for a transfer to complete between
a passive server and a non-passive server. The method should be
called on the passive server with the "Net::FTP" object for the
non-passive server passed as an argument.
abort()
Abort the current data transfer.
quit()
Send the QUIT command to the remote FTP server and close the socket
connection.
Methods for the Adventurous
"quot($cmd[, $args])"
Send a command, that Net::FTP does not directly support, to the
remote server and wait for a response.
Returns most significant digit of the response code.
WARNING This call should only be used on commands that do not
require data connections. Misuse of this method can hang the
connection.
can_inet6()
Returns whether we can use IPv6.
can_ssl()
Returns whether we can use SSL.
The dataconn Class
Some of the methods defined in "Net::FTP" return an object which will
be derived from the "Net::FTP::dataconn" class. See Net::FTP::dataconn
for more details.
Unimplemented
The following RFC959 commands have not been implemented:
"SMNT"
Mount a different file system structure without changing login or
accounting information.
"HELP"
Ask the server for "helpful information" (that's what the RFC says)
on the commands it accepts.
"MODE"
Specifies transfer mode (stream, block or compressed) for file to
be transferred.
"SYST"
Request remote server system identification.
"STAT"
Request remote server status.
"STRU"
Specifies file structure for file to be transferred.
"REIN"
Reinitialize the connection, flushing all I/O and account
information.
EXPORTS
None.
KNOWN BUGS
See <https://rt.cpan.org/Dist/Display.html?Status=Active&Queue=libnet>.
Reporting Bugs
When reporting bugs/problems please include as much information as
possible. It may be difficult for me to reproduce the problem as
almost every setup is different.
A small script which yields the problem will probably be of help. It
would also be useful if this script was run with the extra options
"Debug => 1" passed to the constructor, and the output sent with the
bug report. If you cannot include a small script then please include a
Debug trace from a run of your program which does yield the problem.
SEE ALSO
Net::Netrc(3), Net::Cmd(3), IO::Socket::SSL(3);
ftp(1), ftpd(8);
<https://www.ietf.org/rfc/rfc959.txt>,
<https://www.ietf.org/rfc/rfc2428.txt>,
<https://www.ietf.org/rfc/rfc4217.txt>.
ACKNOWLEDGEMENTS
Henry Gabryjelski <henryg@WPI.EDU <mailto:henryg@WPI.EDU>> - for the
suggestion of creating directories recursively.
Nathan Torkington <gnat@frii.com <mailto:gnat@frii.com>> - for some
input on the documentation.
Roderick Schertler <roderick@gate.net <mailto:roderick@gate.net>> - for
various inputs
AUTHOR
Graham Barr <gbarr@pobox.com <mailto:gbarr@pobox.com>>.
Steve Hay <shay@cpan.org <mailto:shay@cpan.org>> is now maintaining
libnet as of version 1.22_02.
COPYRIGHT
Copyright (C) 1995-2004 Graham Barr. All rights reserved.
Copyright (C) 2013-2017, 2020, 2022 Steve Hay. All rights reserved.
LICENCE
This module is free software; you can redistribute it and/or modify it
under the same terms as Perl itself, i.e. under the terms of either the
GNU General Public License or the Artistic License, as specified in the
LICENCE file.
VERSION
Version 3.15
DATE
20 March 2023
HISTORY
See the Changes file.
perl v5.38.2 2023-11-28 Net::FTP(3pm)
perl 5.38.2 - Generated Mon Dec 9 15:26:25 CST 2024