poe::component::dbiagent::helper(3pm) [debian man page]

DBIAgent::Helper(3pm)					User Contributed Perl Documentation				     DBIAgent::Helper(3pm)

NAME

       POE::Component::DBIAgent::Helper - DBI Query Helper for DBIAgent

SYNOPSYS

	use Socket qw/:crlf/;
	use POE qw/Filter::Line Wheel::Run Component::DBIAgent::Helper/;

	sub _start {
	    my $helper = POE::Wheel::Run ->new(
		    Program	=> sub {
			POE::Component::DBIAgent::Helper->run($self->{dsn},
							      $self->{queries}
							     );
		    },
		    StdoutEvent => 'db_reply',
		    StderrEvent => 'remote_stderr',
		    ErrorEvent	=> 'error',
		    StdinFilter => POE::Filter::Line->new(),
		    StdoutFilter => POE::Filter::Line->new( Literal => CRLF),
		    StderrFilter => POE::Filter::Line->new(),
		   )
	     or carp "Can't create new DBIAgent::Helper: $!
";

	}

	sub query {
	     my ($self, $query, $package, $state, @rest) = @_;

	     $self->{helper}->put(join '|', $query, $package, $state, @rest);
	}

	sub db_reply {
	   my ($kernel, $self, $heap, $input) = @_[KERNEL, OBJECT, HEAP, ARG0];

	   # $input is either the string 'EOF' or a Storable object.

	}

DESCRIPTION

       This is our helper routine for DBIAgent.  It accepts queries on STDIN, and returns the results on STDOUT.  Queries are returned on a row-
       by-row basis, followed by a row consisting of the string 'EOF'.

       Each row is the return value of $sth->fetch, which is an arrayref.  This row is then passed to Storable for transport, and printed to
       STDOUT.	HOWEVER, Storable uses newlines ("
") in its serialized strings, so the Helper is designed to use the "network newline" pair CR
       LF as the line terminator for STDOUT.

       When fetch() returns undef, one final row is returned to the calling state: the string 'EOF'.  Sessions should test for this value FIRST
       when being invoked with input from a query.

   Initialization
       The Helper has one public subroutine, called "run()", and is invoked with two parameters:

       The DSN
	   An arrayref of parameters to pass to DBI->connect (usually a dsn, username, and password).

       The Queries.
	   A hashref of the form Query_Name => "$SQL".	See POE::Component::DBIAgent for details.

BUGS

       I have NO idea what to do about handling signals intelligently.	Specifically, under some circumstances, Oracle will refuse to acknowledge
       SIGTERM (presumably since its libraries are non-reentrant) so sometimes SIGKILL is required to terminate a Helper process.

AUTHOR

       This module has been fine-tuned and packaged by Rob Bloodgood <robb@empire2.com>.  However, most of the code came directly from Fletch
       <fletch@phydeaux.org>, either directly (Po:Co:DBIAgent:Queue) or via his ideas.	Thank you, Fletch!

       However, I own all of the bugs.

       This module is free software; you may redistribute it and/or modify it under the same terms as Perl itself.

perl v5.10.1							    2008-01-18						     DBIAgent::Helper(3pm)

POE::Component::Connection::Keepalive(3pm)		User Contributed Perl Documentation		POE::Component::Connection::Keepalive(3pm)

NAME

       POE::Component::Connection::Keepalive - a wheel wrapper around a kept-alive socket

VERSION

       version 0.271

SYNOPSIS

	 See the SYNOPSIS for POE::Component::Client::Keepalive for a
	 complete working example.

	 my $connection = $response->{connection};
	 $heap->{connection} = $connection;

	 $connection->start( InputEvent => "got_input" );

	 delete $heap->{connection};  # When done with it.

DESCRIPTION

       POE::Component::Connection::Keepalive is a helper class for POE::Component::Client::Keepalive.  It wraps managed sockets, providing a few
       extra features.

       Connection objects free their underlying sockets when they are DESTROYed.  This eliminates the need to explicitly free sockets when you are
       done with them.

       Connection objects manage POE::Wheel::ReadWrite objects internally, saving a bit of effort.

       new
	 Creates a new POE::Component::Connection::Keepalive instance.	It accepts two parameters: A socket handle (socket) and a reference to a
	 POE::Component::Client::Keepalive object to manage the socket when the connection is destroyed.

	   my $conn = POE::Component::Connection::Keepalive->new(
	     socket  => $socket_handle,
	     manager => $poe_component_client_keepalive,
	   );

	 new() is usually called by a POE::Component::Client::Keepalive object.

       start
	 Starts a POE::Wheel::ReadWrite object.  All parameters except Handle for start() are passed directly to POE::Wheel::ReadWrite's
	 constructor.  Handle is provided by the connection object.  start() returns a reference to the new POE::Wheel::ReadWrite object, but it
	 is not necessary to save a copy of that wheel.  The connection object keeps a copy of the reference internally, so the wheel will persist
	 as long as the connection does.  The POE::Wheel::ReadWrite object will be DESTROYed when the connection object is.

	   # Asynchronous connection from Client::Keepalive.
	   sub handle_connection {
	     my $connection_info = $_[ARG0];
	     $_[HEAP]->{connection} = $connection_info->{connection};

	     $heap->{connection}->start(
	       InputEvent => "got_input",
	       ErrorEvent => "got_error",
	     );
	   }

	   # Stop the connection (and the wheel) when an error occurs.
	   sub handle_error {
	     delete $_[HEAP]->{connection};
	   }

       wheel
	 Returns a reference to the internal POE::Wheel::ReadWrite object, so that methods may be called upon it.

	   $heap->{connection}->wheel()->pause_input();

       close
	 Closes the connection immediately. Calls shutdown_input() and shutdown_output() on the wheel also.

SEE ALSO

       POE POE::Component::Client::Keepalive POE::Wheel::ReadWrite

BUGS

       None known.

LICENSE

       This distribution is copyright 2004-2009 by Rocco Caputo.  All rights are reserved.  This distribution is free software; you may
       redistribute it and/or modify it under the same terms as Perl itself.

AUTHOR

       Rocco Caputo <rcaputo@cpan.org>

       Special thanks to Rob Bloodgood.

perl v5.14.2							    2012-05-15				POE::Component::Connection::Keepalive(3pm)