NAME

DDC::Filter - DDC Query utilities: server filters (wrapper sockets)

SYNOPSIS

            

              
              
##========================================================================
## PRELIMINARIES
use DDC::Client;
use DDC::Filter;
##========================================================================
## Constructors etc
$filter = $CLASS_OR_OBJ->new(%args);   ##-- new filter object
##========================================================================
## Logging
$fh = $filter->logfh();                ##-- get log filehandle
$filter = $filter->logclose();         ##-- close log filehandle
undef = logmsg($level,@message);       ##-- log a message
##========================================================================
## Server Methods: run
undef = $filter->run();                ##-- run the wrapper daemon
##========================================================================
## Server Methods: callback
\&callback_sub = $filter->_callback($netserver_generic); ##-- top-level callback
##========================================================================
## Server Methods: filters
$filtered_data = $filter->filterInput($data_from_client);  ##-- input filtering callback
$filtered_data = $filter->filterOutput($data_from_server); ##-- output filtering callback
##========================================================================
## Inherited Methods
# ... any DDC::Client method ...
            
          

DESCRIPTION

Globals

Variable: @ISA

DDC::Filter inherits from DDC::Client.

Variable: %LOGLEVELS

Hash mapping symbolic log levels to numeric values, exportable.

Constructors etc

new

            

              
              
$filter = $CLASS_OR_OBJ->new(%args);
            
          

%args:

            

              
              
(
 connect=>\%connectArgs,  ##-- passed to IO::Socket::INET->new(), ##-- client args
 bind   =>\%bindArgs,     ##-- args to NetServer::Generic->new()
 logfile  => $filename,   ##-- for logging (defualt=&STDERR)
 loglevel => $level,      ##-- log level
)
            
          

additional object structure:

            

              
              
(
 server=>$server,         ##-- a NetServer::Generic object for listening
)
            
          

default %connectArgs:

            

              
              
PeerAddr=>'localhost',
PeerPort=>50000,
Proto=>'tcp',
Type=>SOCK_STREAM,
Blocking=>1,
            
          

(for connecting to the underlying DDC server).

default %bindArgs:

            

              
              
#hostname=>'localhost',
port=>$60000,
mode=>"forking",
allowed=>['127.0.0.1'],
listen=>128,
timeout=>60,
            
          

(for accepting incoming client connections).

Logging

logfh

            

              
              
$fh = $filter->logfh();
            
          

Get logging filehandle.

logclose

            

              
              
$filter = $filter->logclose();
            
          

Close log filehandle.

logmsg

            

              
              
undef = logmsg($level,@message);
            
          

Potentially log a message at $level.

Server Methods: run

run

            

              
              
undef = $filter->run();
            
          

Run the server, accepting incoming connections and calling callback(s) for each incoming query.

Server Methods: callback

_callback

            

              
              
\&callback_sub = $filter->_callback($netserver_generic);
            
          

Generic NetServer::Generic callback, called for each client. The default implmentation calls the filterInput() and filterOutput() methods, which should be sufficient for many applications.

Server Methods: filters

filterInput

            

              
              
$filtered_data = $filter->filterInput($data_from_client);
            
          

This method may be overridden in derived classes to perform filtering of data to be passed to the real DDC server.

The default implementation just returns $data_from_client unchanged.

filterOutput

            

              
              
$filtered_data = $filter->filterOutput($data_from_server);
            
          

This method may be overridden in derived classes to perform filtering of data to be passed back to the querying client.

The default implementation just returns $data_from_server unchanged.

AUTHOR

Bryan Jurish <moocow@cpan.org>

COPYRIGHT AND LICENSE

Copyright (C) 2006-2016 by Bryan Jurish

This package is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.14.2 or, at your option, any later version of Perl 5 you may have available.