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Net::Cmd(3pm)          Perl Programmers Reference Guide          Net::Cmd(3pm)




NAME

       Net::Cmd - Network Command class (as used by FTP, SMTP etc)


SYNOPSIS

           use Net::Cmd;

           @ISA = qw(Net::Cmd);


DESCRIPTION

       "Net::Cmd" is a collection of methods that can be inherited by a sub
       class of "IO::Handle". These methods implement the functionality
       required for a command based protocol, for example FTP and SMTP.


USER METHODS

       These methods provide a user interface to the "Net::Cmd" object.

       debug ( VALUE )
           Set the level of debug information for this object. If "VALUE" is
           not given then the current state is returned. Otherwise the state
           is changed to "VALUE" 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 "VALUE" 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 static 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.


CLASS METHODS

       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 true 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., CMD_ERROR 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 undef upon failure.

           NOTE: 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 undef upon
           failure.

       tied_fh ()
           Returns a filehandle tied to the Net::Cmd object.  After issuing a
           command, you may read from this filehandle using read() 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.


PSEUDO RESPONSES

       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 DEF_REPLY_CODE() 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
           _set_status_closed() method can be overridden to set a different
           message (by calling set_status()) 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 _set_status_timeout() method can be overridden to
           set a different message (by calling set_status()) or otherwise trap
           this error.


EXPORTS

       "Net::Cmd" exports six subroutines, five of these, "CMD_INFO",
       "CMD_OK", "CMD_MORE", "CMD_REJECT" and "CMD_ERROR", correspond to
       possible results of "response" and "status". The sixth is
       "CMD_PENDING".


AUTHOR

       Graham Barr <gbarr@pobox.com>

       Steve Hay <shay@cpan.org> is now maintaining libnet as of version
       1.22_02


COPYRIGHT

       Versions up to 2.29_1 Copyright (c) 1995-2006 Graham Barr. All rights
       reserved.  Changes in Version 2.29_2 onwards Copyright (C) 2013-2014
       Steve Hay.  All rights reserved.

       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.



perl v5.24.0                      2016-03-01                     Net::Cmd(3pm)

perl 5.24 - Generated Fri Nov 18 16:30:24 CST 2016
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