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.

           Set the level of debug information for this object. If
           no argument is given then the current state is
           returned. Otherwise the state is changed to $valueand
           the previous state returned.  Different packages may
           implement different levels of debug but, a  non-zero
           value result 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

       code ()
           Returns the 3-digit code from the last command. If a
           command is pending then the value 0 is returned

       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.
           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.

       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 ( 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 a
           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., undef is returned.

           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 list.

       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.

       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.

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>

COPYRIGHT

       Copyright (c) 1995-1997 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.