net::ftp(3)

NAME

Net::FTP - FTP Client class

SYNOPSIS

use Net::FTP;
$ftp = Net::FTP->new("some.host.name", Debug => 0);
$ftp->login("anonymous",'-anonymous@');
$ftp->cwd("/pub");
$ftp->get("that.file");
$ftp->quit;

DESCRIPTION

"Net::FTP" is a class implementing a simple FTP client in
Perl as described in RFC959. It provides wrappers for a
subset of the RFC959 commands.

OVERVIEW

FTP stands for File Transfer Protocol. It is a way of
transferring files between networked machines. The proto
col 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 trans
ferring 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 trans
late the ends of lines to a standard representation which
the receiver will then translate back into their local
representation. EBCDIC indicates the file being trans
ferred 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).

CONSTRUCTOR

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.; "OPTIONS" are passed in a hash like fashion, using key
and value pairs. Possible options are:; 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 connec
tion is made to the firewall machine and the string
@hostname is appended to the login identifier. This
kind of setup is also refered 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; Timeout - Set a timeout value (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. This is not
usually required except for some dumb servers, and
some firewall configurations. This can also be set by
the environment variable "FTP_PASSIVE".; Hash - If given a reference to a file handle (e.g.,
"TDERR"), 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.; If the constructor fails undef will be returned and an
error message will be in $@

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.

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 anony_
mous then anonymous@ will be used for password.; If the connection is via a firewall then the "autho
rize" method will be called with no arguments.
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.
type (TYPE [, ARGS]): This method will send the TYPE command to the remote
FTP server to change the type of data transfer. The
return value is the previous value.
ascii ([ARGS]) binary([ARGS]) ebcdic([ARGS]) byte([ARGS]): Synonyms for "type" with the first arguments set cor
rectly; NOTE ebcdic and byte are not fully supported.
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 direc
tory to the root directory.
cdup (): Change directory to the parent of the current direc
tory.
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 ): Remove the directory with the name "DIR".
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.
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 refer
ence 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 refer
ence 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 transfered, 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 encoun
tered 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 file
name if "REMOTE_FILE" is not given.; NOTE: If for some reason the transfer does not com
plete and an error is returned then the contents that
had been transfered 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 file
name 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
transfered 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 argu
ment is true but not a reference to a file handle
glob, then TDERR 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.
The following methods can return different results depend ing 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 call ing 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 ] ): Send a "PORT" 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 (): Tell the server to go into passive mode. Returns the
text that represents the port on which the server is
listening, this text is in a suitable form to sent to
another ftp server using the "port" 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 com
plete 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
"Net::FTP" inherits from "Net::Cmd" so methods defined in "Net::Cmd" may be used to send commands to the remote FTP server.
quot (CMD [,ARGS]): Send a command, that Net::FTP does not directly sup
port, 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.

THE dataconn CLASS

Some of the methods defined in "Net::FTP" return an object
which will be derived from this class.The dataconn class
itself is derived from the "IO::Socket::INET" class, so
any normal IO operations can be performed. However the
following methods are defined in the dataconn class and IO
should be performed using these.

read ( BUFFER, SIZE [, TIMEOUT ] ): Read "SIZE" bytes of data from the server and place it
into "BUFFER", also performing any <CRLF> translation
necessary. "TIMEOUT" is optional, if not given, the
timeout value from the command connection will be
used.; Returns the number of bytes read before any <CRLF>
translation.
write ( BUFFER, SIZE [, TIMEOUT ] ): Write "SIZE" bytes of data from "BUFFER" to the
server, also performing any <CRLF> translation neces
sary. "TIMEOUT" is optional, if not given, the timeout
value from the command connection will be used.; Returns the number of bytes written before any <CRLF>
translation.
bytes_read (): Returns the number of bytes read so far.
abort (): Abort the current data transfer.
close (): Close the data connection and get a response from the
FTP server. Returns true if the connection was closed
successfully and the first digit of the response from
the server was a '2'.

UNIMPLEMENTED

The following RFC959 commands have not been implemented:

ALLO: Allocates storage for the file to be transferred.
SMNT: Mount a different file system structure without chang
ing 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.

REPORTING BUGS

When reporting bugs/problems please include as much infor
mation as possible. It may be difficult for me to repro
duce 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 con
structor, 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.

AUTHOR

Graham Barr <gbarr@pobox.com>

USE EXAMPLES

For an example of the use of Net::FTP see

http://www.csh.rit.edu/~adam/Progs/autoftp-2.0.tar.gz: "autoftp" is a program that can retrieve, send, or
list files via the FTP protocol in a non-interactive
manner.

CREDITS

Henry Gabryjelski <henryg@WPI.EDU> - for the suggestion of
creating directories recursively.

Nathan Torkington <gnat@frii.com> - for some input on the
documentation.

Roderick Schertler <roderick@gate.net> - for various
inputs

COPYRIGHT

$Id: //depot/libnet/Net/FTP.pm#68 $

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