Net::Cmd - man - phpman

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::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()".

  Public Methods
    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 *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.

  Protected 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
    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
        *None*.

    Export Tags
        *None*.

KNOWN BUGS
    See <https://rt.cpan.org/Dist/Display.html?Status=Active&Queue=libnet>.

AUTHOR
    Graham Barr <gbarr AT pobox.com <mailto:gbarr AT pobox.com>>.

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

COPYRIGHT
    Copyright (C) 1995-2006 Graham Barr. All rights reserved.

    Copyright (C) 2013-2016, 2020 Steve Hay. All rights reserved.

LICENCE
    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.

VERSION
    Version 3.13

DATE
    23 Dec 2020

HISTORY
    See the Changes file.