Edward Kawas > MOBY > MOBY::Async

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NAME ^

MOBY::Async - a set of tools for Asynchronous MOBY Services

SYNOPSIS ^

This is a set of tools for providing and invoking Asynchronous MOBY Services.

FORMER AUTHORS ^

Enrique de Andres Saiz (enrique.deandres@pcm.uam.es) - INB GNHC-1 (Madrid Science Park, Spain).

MAINTAINERS ^

Jose Manuel Rodriguez Carrasco (jmrodriguez@cnio.es) - INB GN-2 (Centro Nacional de Investigaciones Oncologicas, Spain).

Jose Maria Fernandez Gonzalez (jmfernandez@cnio.es) - INB GN-2 (Centro Nacional de Investigaciones Oncologicas, Spain).

DESCRIPTION ^

MOBY::Async package provides a set of modules for working with Asynchronous MOBY Services, both from client and server side. It consists of the following modules:

MOBY::Async::SimpleServer

It provides a simple class that can be extended to build file based asynchronous services.

MOBY::Async::Service

It provides a class to invoke asynchronous services.

MOBY::Async::LSAE

It provides functionalities to work with LSAE analysis event blocks.

MOBY::Async::WSRF

It extends WSRF::Lite perl module and provides everything required for MOBY::Async::SimpleServer class.

EXAMPLE ^

The following example implements the classic "Hello World" service with a delay of 60 seconds.

From the server side, an asynchronous service is very similar to the traditional synchronous BioMOBY services. It is composed by a cgi (dispatcher.cgi) and a Perl module wich extends MOBY::Async::SimpleServer class (HelloWorld.pm).

dispatcher.cgi

  #!/usr/bin/perl
  use lib "/path/to/my/libs";
  use strict;
  use SOAP::Transport::HTTP;
  use MOBY::Async::WSRF;
  use MOBY::Async::SimpleServer;
  use HelloWorld;

  my $server = new SOAP::Transport::HTTP::CGI;
  $server->serializer(WSRF::Serializer->new);
  $server->deserializer(WSRF::Deserializer->new);
  $server->on_action(sub{});
  $server->dispatch_with({
    $WSRF::Constants::MOBY.'#sayHello'        => 'HelloWorld',
    $WSRF::Constants::MOBY.'#sayHello_submit' => 'HelloWorld',
    $WSRF::Constants::WSRPW.'/GetResourceProperty/GetResourcePropertyRequest' => 'MOBY::Async::SimpleServer',
    $WSRF::Constants::WSRPW.'/GetMultipleResourceProperties/GetMultipleResourcePropertiesRequest' => 'MOBY::Async::SimpleServer',
    $WSRF::Constants::WSRLW.'/ImmediateResourceTermination/DestroyRequest' => 'MOBY::Async::SimpleServer',
  });
  $server->handle();

HelloWorld.pm

  package HelloWorld;
  use strict;
  use MOBY::CommonSubs qw(:all);
  use MOBY::Async::SimpleServer;
  use base qw(MOBY::Async::SimpleServer);

  # This environment variable must be set - it is used internally
  # by MOBY::Async::SimpleServer class
  $ENV{AUTHURI} = 'your.auth.com';

  # This variable is a subroutine which carries out the core of the service
  my $sayHello = sub {
    my ($caller, $data) = @_;
    my $response = '';

    my @queries = getInputs($data);
    return responseHeader($ENV{AUTHURI}).responseFooter() unless (scalar(@queries));

    foreach my $query (@queries) {
      my $queryID = getInputID($query);
      $response .= simpleResponse('Hello, Asynchronous BioMOBY world!!!', 'message', $queryID);
      sleep 60;
    }

    return SOAP::Data->value(responseHeader($ENV{AUTHURI}).$response.responseFooter())->type('string');
  };

  # This is the method which answers to synchronous requests
  sub sayHello {
    my $self = shift @_;
    # Here you can choose between sync or error
    return $self->sync($sayHello, 180, @_);
    #return $self->error(@_);
  }

  # This is the method which answers to asynchronous requests
  sub sayHello_submit {
    my $self = shift @_;
    return $self->async($sayHello, @_);
  }

  1;  

A client which wishes to run an asynchronous service as HelloWorld must carry out the following steps:

1. First we have a sayHello_submit (servicename_submit) invocation, which returns an EPR, that it is a "ticket" unique for all the async services of the service provider (or at least in that particular server). sayHello_submit is called with a normal BioMOBY input but it returns an EPR which will be included into the SOAP header of all the subsequent calls (to say which batch-call).

2. After this, a polling is done by invocating GetMultipleResourceProperties operation. GetMultipleResourceProperties retrieve the content of one or several properties. In this case, as we are trying to determine if a batch-call has finished, we ask all status properties (status_queryID). The status returned for each status property is in LSAE format. Unless all status properties represent that execution for its respective query identifier is finished, we sleep a time and we retry the polling again.

3. Once all status properties represent a finished execution, there is another GetMultipleResourceProperties invocation asking for the result properties. The content of the returned result properties are in BioMOBY format.

4. The client also explicitly calls the WSRF Destroy operation to clean the results at the service side.

To do this, a client relies on MOBY::Async::Service class, whose use is very similar to MOBY::Client::Service class available for synchronous services:

  # By default, silent is true, then no messages about the progress are reported
  my $S = MOBY::Async::Service->new(service => $wsdl);
  $S->silent(0); 
  my $response = $S->execute(XMLinputlist => [
    ['myArtName00', '<String namespace="" id=""><![CDATA[Hey No. 0 !!!]]></String>'],
    ['myArtName01', '<String namespace="" id=""><![CDATA[Hey No. 1 !!!]]></String>']
  ]);
  print "$response\n";

Additionally, MOBY::Async::Service class provides methods to carry out individually the steps previously described:

  my $S = MOBY::Async::Service->new(service => $wsdl);
  my ($EPR, @queryIDs) = $S->submit(XMLinputlist => [
    ['myArtName00', '<String namespace="" id=""><![CDATA[Hey No. 0 !!!]]></String>'],
    ['myArtName01', '<String namespace="" id=""><![CDATA[Hey No. 1 !!!]]></String>']
  ]);
  #...
  my @status = $S->poll($EPR, @queryIDs);
  #...
  my @response = $S->result($EPR, @queryIDs);
  #...
  $S->destroy($EPR);

FURTHER READING ^

MOBY::Async::SimpleServer, MOBY::Async::Service, MOBY::Async::LSAE and MOBY::Async::WSRF Perl modules documentation.

Asynchronous BioMOBY Services Specification: http://biomoby.open-bio.org/CVS_CONTENT/moby-live/Docs/asyncDocs/BioMOBY%20Asynchronous%20Service%20Specification%20v2.4.2.pdf

WSRF Specifications: http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=wsrf#technical

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