Net::Cmd(3p) Perl Programmers Reference Guide Net::Cmd(3p) #
Net::Cmd(3p) Perl Programmers Reference Guide Net::Cmd(3p)
NNAAMMEE #
Net::Cmd - Network Command class (as used by FTP, SMTP etc)
SSYYNNOOPPSSIISS #
use Net::Cmd;
@ISA = qw(Net::Cmd);
DDEESSCCRRIIPPTTIIOONN #
"Net::Cmd" is a collection of methods that can be inherited by a sub-
class of "IO::Socket::INET". These methods implement the functionality
required for a command based protocol, for example FTP and SMTP.
If your sub-class does not also derive from "IO::Socket::INET" or similar
(e.g. "IO::Socket::IP", "IO::Socket::INET6" or "IO::Socket::SSL") then
you must provide the following methods by other means yourself: "close()"
and "timeout()".
PPuubblliicc MMeetthhooddss These methods provide a user interface to the “Net::Cmd” object.
"debug($level)"
Set the level of debug information for this object. If $level is not
given then the current state is returned. Otherwise the state is
changed to $level and the previous state returned.
Different packages may implement different levels of debug but a non-
zero value results in copies of all commands and responses also being
sent to STDERR.
If $level is "undef" then the debug level will be set to the default
debug level for the class.
This method can also be called as a _s_t_a_t_i_c method to set/get the
default debug level for a given class.
"message()"
Returns the text message returned from the last command. In a scalar
context it returns a single string, in a list context it will return
each line as a separate element. (See "PSEUDO RESPONSES" below.)
"code()"
Returns the 3-digit code from the last command. If a command is
pending then the value 0 is returned. (See "PSEUDO RESPONSES" below.)
"ok()"
Returns non-zero if the last code value was greater than zero and
less than 400. This holds true for most command servers. Servers
where this does not hold may override this method.
"status()"
Returns the most significant digit of the current status code. If a
command is pending then "CMD_PENDING" is returned.
"datasend($data)"
Send data to the remote server, converting LF to CRLF. Any line
starting with a '.' will be prefixed with another '.'. $data may be
an array or a reference to an array. The $data passed in must be
encoded by the caller to octets of whatever encoding is required,
e.g. by using the Encode module's "encode()" function.
"dataend()"
End the sending of data to the remote server. This is done by
ensuring that the data already sent ends with CRLF then sending
'.CRLF' to end the transmission. Once this data has been sent
"dataend" calls "response" and returns true if "response" returns
CMD_OK. #
PPrrootteecctteedd MMeetthhooddss These methods are not intended to be called by the user, but used or over-ridden by a sub-class of “Net::Cmd”
"debug_print($dir, $text)"
Print debugging information. $dir denotes the direction _t_r_u_e being
data being sent to the server. Calls "debug_text" before printing to
STDERR. #
"debug_text($dir, $text)"
This method is called to print debugging information. $text is the
text being sent. The method should return the text to be printed.
This is primarily meant for the use of modules such as FTP where
passwords are sent, but we do not want to display them in the
debugging information.
"command($cmd[, $args, ... ])"
Send a command to the command server. All arguments are first joined
with a space character and CRLF is appended, this string is then sent
to the command server.
Returns undef upon failure.
"unsupported()"
Sets the status code to 580 and the response text to 'Unsupported
command'. Returns zero.
"response()"
Obtain a response from the server. Upon success the most significant
digit of the status code is returned. Upon failure, timeout etc.,
_C_M_D___E_R_R_O_R is returned.
"parse_response($text)"
This method is called by "response" as a method with one argument. It
should return an array of 2 values, the 3-digit status code and a
flag which is true when this is part of a multi-line response and
this line is not the last.
"getline()"
Retrieve one line, delimited by CRLF, from the remote server. Returns
_u_n_d_e_f upon failure.
NNOOTTEE: If you do use this method for any reason, please remember to
add some "debug_print" calls into your method.
"ungetline($text)"
Unget a line of text from the server.
"rawdatasend($data)"
Send data to the remote server without performing any conversions.
$data is a scalar. As with "datasend()", the $data passed in must be
encoded by the caller to octets of whatever encoding is required,
e.g. by using the Encode module's "encode()" function.
"read_until_dot()"
Read data from the remote server until a line consisting of a single
'.'. Any lines starting with '..' will have one of the '.'s removed.
Returns a reference to a list containing the lines, or _u_n_d_e_f upon
failure.
"tied_fh()"
Returns a filehandle tied to the Net::Cmd object. After issuing a
command, you may read from this filehandle using rreeaadd(()) or <>. The
filehandle will return EOF when the final dot is encountered.
Similarly, you may write to the filehandle in order to send data to
the server after issuing a command that expects data to be written.
See the Net::POP3 and Net::SMTP modules for examples of this.
PPsseeuuddoo RReessppoonnsseess Normally the values returned by “message()” and “code()” are obtained from the remote server, but in a few circumstances, as detailed below, “Net::Cmd” will return values that it sets. You can alter this behavior by overriding DDEEFF__RREEPPLLYY__CCOODDEE(()) to specify a different default reply code, or overriding one of the specific error handling methods below.
Initial value
Before any command has executed or if an unexpected error occurs
"code()" will return "421" (temporary connection failure) and
"message()" will return undef.
Connection closed
If the underlying "IO::Handle" is closed, or if there are any read or
write failures, the file handle will be forced closed, and "code()"
will return "421" (temporary connection failure) and "message()" will
return "[$pkg] Connection closed" (where $pkg is the name of the
class that subclassed "Net::Cmd"). The __sseett__ssttaattuuss__cclloosseedd(()) method
can be overridden to set a different message (by calling
sseett__ssttaattuuss(())) or otherwise trap this error.
Timeout
If there is a read or write timeout "code()" will return "421"
(temporary connection failure) and "message()" will return "[$pkg]
Timeout" (where $pkg is the name of the class that subclassed
"Net::Cmd"). The __sseett__ssttaattuuss__ttiimmeeoouutt(()) method can be overridden to
set a different message (by calling sseett__ssttaattuuss(())) or otherwise trap
this error.
EEXXPPOORRTTSS #
The following symbols are, or can be, exported by this module:
Default Exports
“CMD_INFO”, “CMD_OK”, “CMD_MORE”, “CMD_REJECT”, “CMD_ERROR”, #
“CMD_PENDING”. #
(These correspond to possible results of "response()" and
"status()".)
Optional Exports
_N_o_n_e.
Export Tags
_N_o_n_e.
KKNNOOWWNN BBUUGGSS #
See <https://rt.cpan.org/Dist/Display.html?Status=Active&Queue=libnet>.
AAUUTTHHOORR #
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.
CCOOPPYYRRIIGGHHTT #
Copyright (C) 1995-2006 Graham Barr. All rights reserved.
Copyright (C) 2013-2016, 2020 Steve Hay. All rights reserved.
LLIICCEENNCCEE #
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
_L_I_C_E_N_C_E file.
VVEERRSSIIOONN #
Version 3.14
DDAATTEE #
23 Dec 2020
HHIISSTTOORRYY #
See the _C_h_a_n_g_e_s file.
perl v5.36.3 2023-02-15 Net::Cmd(3p)