 |
Index for
Section 3 |
|
 |
Alphabetical
listing for N |
|
 |
Bottom of
page |
|
Net::FTP(3)
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 a subset of the RFC959 commands.
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).
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.
"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 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., "\*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 IO::Socket::INET
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 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.
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.
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.
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 transfered 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 mazimum 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 transfering 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 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 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 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 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 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 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.
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 ] )
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 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
"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 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.
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 necessary. "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:
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.
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.
AUTHOR
Graham Barr <gbarr@pobox.com>
SEE ALSO
Net::Netrc Net::Cmd
ftp(1), ftpd(8), RFC 959
http://www.cis.ohio-state.edu/htbin/rfc/rfc959.html
USE EXAMPLES
For an example of the use of Net::FTP see
http://www.csh.rit.edu/~adam/Progs/
"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
Copyright (c) 1995-2004 Graham Barr. All rights reserved. This program is
free software; you can redistribute it and/or modify it under the same
terms as Perl itself.
|
Index for
Section 3 |
|
|
Alphabetical
listing for N |
|
 |
Top of
page |
|