oscalimero has asked for the wisdom of the Perl Monks concerning the following question:

I've been having some trouble sending session references and coderefs to a foreign
kernel and i was hoping someone here would be able to give me some advice.

On my example i have two kernels: ikc_server and ikc_client. The client aplication
will start by post an event (with an argument) on the server. Then the server will
grab the argument for processing. When it finish it will postback the result to the
client session.

This works fine with proxy sender by setting an external reference
(http://search.cpan.org/~gwyn/POE-Component-IKC-0.2200/IKC/Responder.pm#PROXY_SENDER).

I want to know if it is possible to send session references of IKC Client to IKC
Server and then use that coderef to postback from the IKC Server to the Client, so
that i wont be need to set an external reference for the sending session. Something
like this: 

    # create postback
    my $postback = $_[SESSION]->postback("status");

    $kernel->post( 'IKC', 'post', 'poe://Server/ServerTest/compute', {
+value=>$value, postback=>$postback} );

[download]

An example would help a lot.

Thanks in advance

Here is the code

----------- ikc_server ----------- 

    #!/var/bin/perl

    use warnings;
    use strict;

    use POE qw(Component::IKC::Server);
    use Data::Dumper::Simple;

    POE::Component::IKC::Server->spawn(
        port =>'12345',
        name => 'Server',
    );

    POE::Session->create(
        inline_states => {
            _start         => \&start,
            compute        => \&compute,
            finish         => \&finish,
            _stop          => \&stop,   
    },
    );

    print "$$: Running server...\n";
    POE::Kernel->run();
    print "$$: Server exited...\n";
    exit();

    sub start {
        my ($kernel) = $_[KERNEL];

        my $service_name = 'ServerTest';
        $kernel->alias_set($service_name);
        $kernel->post( IKC => publish => $service_name, ['compute'] );
    return;
    }

    sub compute {
    my ($kernel, $arg) = @_[KERNEL, ARG0];
        my $sender_id = $_[SENDER]->ID;

    print "\n\t sub compute ", $arg;
        $kernel->refcount_increment( $sender_id, 'MYREFCOUNT' );
        $kernel->yield( 'finish', $arg+1, $sender_id ); 
    return;
    }

    sub finish {
        my ($kernel, $arg, $sender_id ) = @_[KERNEL, ARG0, ARG1];

        print "\n\t sub finish ", $arg, "\n";
        $kernel->post($sender_id, 'status', $arg);
        $kernel->refcount_decrement( $sender_id, 'MYREFCOUNT' );
        return;
    }

    sub stop {
        my ( $kernel ) = $_[KERNEL];

        print "\n STOP \n";
        $kernel->alias_remove('ServerTest');
    }

[download]
----------- ikc_client ----------- 
    #!/var/bin/perl

    use warnings;
    use strict;

    use POE;
    use POE qw(Component::IKC::Client);
    use Data::Dumper::Simple;

    POE::Component::IKC::Client->spawn(
         port =>'12345',
         name=>"Client$$",
         on_connect=>\&create_sessions,
    );

    sub create_sessions {
        POE::Session->create(
            inline_states => {
                _start         => \&start,
                execute        => \&execute,
                status         => \&status,
                _stop          => \&stop,
           },
        );
    }

    print "$$: Running client...\n";
    POE::Kernel->run();
    print "$$: Client exited...\n";
    exit();

    sub start {
        my ( $kernel, $session ) = @_[ KERNEL, SESSION ];
        my $service_name         = 'ClientTest';

        $kernel->alias_set($service_name);
        $kernel->post( IKC => publish => $service_name, ['status'] );
        $kernel->yield( 'execute' );
        return;
    }

    sub execute {
        my ( $kernel, $session ) = @_[ KERNEL, SESSION ];
        my $value                = 0;

        $value = $_[ARG0] unless (! defined $_[ARG0]);
        print "\n\t sub execute... $value";
        $kernel->post( 'IKC', 'post', 'poe://Server/ServerTest/compute
+', $value );
        return;
    }

    sub status {
        my ($kernel) = $_[KERNEL];

        print "\n\t sub status... ", $_[ARG0], "\n";
        sleep(1);
        $kernel->yield('execute', $_[ARG0]);   
        return;
    }

    sub stop {
        my ( $kernel ) = $_[KERNEL];

        print "\n STOP \n";
        $kernel->alias_remove('ClientTest');
    }

[download]

Replies are listed 'Best First'.
Re: POE Component IKC - Sending session references and coderefs to a foreign kernel
by ikegami (Patriarch) on Jun 17, 2009 at 16:02 UTC

    If you ensure the code ref doesn't get freed, all you need is a means of serializing and deserializing the code reference. The following should do the trick (including keeping the code ref alive): 

    sub submit_request {
    my ($code_ref, ...) = @_;
    my $callback_id = "$code_ref";
    $registered{ $callback_id } ||= [ 0, $code_ref ];
    ++$registered{ $callback_id }[0];
    _submit_request($callback_id, @_);
}

    [download]
    sub on_response {
    my $callback_id = shift;
    my $code_ref = $registered{ $callback_id }[1]
        or croak(...);
    --$registered{ $callback_id }[0]
        or delete( $registered{ $callback_id } );
    $code_ref->(@_);
}

    [download]

    Assumptions:

    • The response is always handled by the process that issued the request.
    • There is only one response per request.
[reply]
[d/l]
[select]
      Thanks for help. I use POCO::IKC::Server with POCO::IKC::Specifier and POCO::IKC::Client with POCOIKC::Responder to solve the issue
[reply]

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