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.