Two versions of the code for the SADI Web Service demonstrated at the Using the Semantic Web for faster (Bio-)Research workshop hosted by the Swiss Institute for Bioinformatics, Geneva, December, 2015. The first version of the code is a bare-bones service that consumes individuals with height and weight and returns individuals with a BMI. The second piece of code is functionally identical to the first, but highlights the small changes required to make the service a NanoPublisher (NanoPublishing services respond to Accept n-quads HTTP headers by returning NanoPublications, rather than just a stream of triples)

1. #!/usr/local/bin/perl
package GetMyBMI; # a SADI Service for BMI Calculation
use strict;
use warnings;
#use base 'SADI::Simple::AsyncService';
use base 'SADI::Simple::SyncService';
my $config = {
ServiceName => 'GetMyBMI', # any name you like
ServiceURI => 'http://linkeddata.systems/cgi-bin/SADI/GetMyBMI.pl', #URL of this script
Description => 'A BMI calculator',
InputClass => 'http://linkeddata.systems/ontologies/SADITutorial.owl#PatientData',
OutputClass => 'http://linkeddata.systems/ontologies/SADITutorial.owl#PatientBMI',
Authority => 'wilkinsonlab.info', # domain of organization providing service
Provider => 'markw@illuminae.com', # contact e-mail address of service provider
};
my $service = GetMyBMI->new(%$config);
$service->handle_cgi_request;
#-----------------------------------------------------------------
# SERVICE IMPLEMENTATION
#-----------------------------------------------------------------
use RDF::Trine::Node::Resource;
use RDF::Trine::Node::Literal;
use RDF::Trine::Statement;
sub process_it {
my ($self, $inputs, $input_model, $output_model) = @_;
# $inputs - ref to an array of RDF::Trine::Node::Resource
# $input_model - an RDF::Trine::Model containing the input RDF data
# $output_model - an RDF::Trine::Model containing the output RDF data
my $heightp = RDF::Trine::Node::Resource->new(
'http://mged.sourceforge.net/ontologies/MGEDOntology.owl#has_height');
my $weightp = RDF::Trine::Node::Resource->new(
'http://linkeddata.systems/ontologies/SADITutorial.owl#has_mass');
my $BMIp = RDF::Trine::Node::Resource->new(
'http://sadiframework.org/examples/bmi.owl#BMI');
foreach my $input (@$inputs) {
# retrieve the height and weight node from each input
my ($height) = $input_model->objects($input, $heightp);
my ($weight) = $input_model->objects($input, $weightp);
$height = $height->value;
$weight = $weight->value;
my $BMI = $weight/($height * $height);
my $BMI_literal = RDF::Trine::Node::Literal->new($BMI);
# The output statement is about the $input as the subject node!!
my $statement = RDF::Trine::Statement->new($input, $BMIp, $BMI_literal);
$output_model->add_statement($statement);
}
}

2. #!/usr/local/bin/perl
package GetMyBMI;
use strict;
use warnings;
use base 'SADI::Simple::SyncService';
use Log::Log4perl qw(:easy);
Log::Log4perl->easy_init($WARN);
#Log::Log4perl->easy_init($DEBUG);
my $config = {
ServiceName => 'GetMyBMI', # any name you like
ServiceURI => 'http://linkeddata.systems/cgi-bin/SADI/GetMyBMI.pl',
Description => 'A BMI calculator',
InputClass => 'http://linkeddata.systems/ontologies/SADITutorial.owl#PatientData',
OutputClass => 'http://linkeddata.systems/ontologies/SADITutorial.owl#PatientBMI',
Authority => 'wilkinsonlab.info', # domain of organization providing service
Provider => 'markw@illuminae.com', # contact e-mail address of service provider
NanoPublisher => 1, # I want to be a NanoPublisher
};
my $service = GetMyBMI->new(%$config);
$service->handle_cgi_request;
use RDF::Trine::Node::Resource;
use RDF::Trine::Node::Literal;
use RDF::Trine::Statement;
sub process_it {
my ($self, $inputs, $input_model, $output_model) = @_;
# $inputs - ref to an array of RDF::Trine::Node::Resource
# $input_model - an RDF::Trine::Model containing the input RDF data
# $output_model - an RDF::Trine::Model containing the output RDF data
my $heightp = RDF::Trine::Node::Resource->new(
'http://mged.sourceforge.net/ontologies/MGEDOntology.owl#has_height');
my $weightp = RDF::Trine::Node::Resource->new(
'http://linkeddata.systems/ontologies/SADITutorial.owl#has_mass');
my $BMIp = RDF::Trine::Node::Resource->new(
'http://sadiframework.org/examples/bmi.owl#BMI');
foreach my $input (@$inputs) {
my ($height) = $input_model->objects($input, $heightp);
my ($weight) = $input_model->objects($input, $weightp);
$height = $height->value;
$weight = $weight->value;
my $BMI = $weight/($height * $height);
DEBUG("BMI $BMIn");
my $BMI_literal = RDF::Trine::Node::Literal->new($BMI);
my $statement = RDF::Trine::Statement->new($input, $BMIp, $BMI_literal);
$output_model->add_statement($statement, $input);
$output_model->nanopublish_result_for($input);
}
}