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.

       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.

       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  program  is  free  software;  you can redistribute it and/or modify it under the same terms as Perl
       itself.

perl v5.22.1                                       2020-10-19                                    Net::Cmd(3perl)