Net::Cmd - Network Command class (as used by FTP, SMTP etc)
- use Net::Cmd;
- @ISA = qw(Net::Cmd);
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()
.
These methods provide a user interface to the Net::Cmd
object.
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.
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.)
Returns the 3-digit code from the last command. If a command is pending then the value 0 is returned. (See PSEUDO RESPONSES below.)
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.
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.
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.
These methods are not intended to be called by the user, but used or
over-ridden by a sub-class of Net::Cmd
Print debugging information. DIR
denotes the direction true being
data being sent to the server. Calls debug_text
before printing to
STDERR.
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.
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.
Sets the status code to 580 and the response text to 'Unsupported command'. Returns zero.
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.
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.
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.
Unget a line of text from the server.
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 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.
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.
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.
Before any command has executed or if an unexpected error occurs
code()
will return "421" (temporary connection failure) and
message()
will return undef.
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 $pkg is the name of the class that subclassed Net::Cmd
).
The _set_status_closed() method can be overridden to set a different
message (by calling set_status()) or otherwise trap this error.
If there is a read or write timeout code()
will return "421"
(temporary connection failure) and message()
will return
"[$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.
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
.
Graham Barr <[email protected]>
Steve Hay <[email protected]> is now maintaining libnet as of version 1.22_02
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.