NAME
    WQS::SPARQL - Simple SPARQL query for Wikidata Query Service.

SYNOPSIS
     use WQS::SPARQL;

     my $obj = WQS::SPARQL->new(%params);
     my $ret_hr = $obj->query($sparql);
     my $count = $obj->query_count($sparql_count);

METHODS
  "new"
     my $obj = WQS::SPARQL->new(%params);

    Constructor.

    *   "agent"

        User agent.

        Default value is 'WQS::SPARQL (__VERSION__)'.

    *   "lwp_user_agent"

        LWP::UserAgent object.

        Default value is instance of LWP::UserAgent with constructor 'agent'
        parameter.

    *   "query_site"

        Query site.

        Default value is 'query.wikidata.org'.

    *   "sparql_endpoint"

        SPARQL endpoint.

        Default value is '/bigdata/namespace/wdq/sparql'.

    *   "verbose"

        Verbose mode.

        Default value is 0.

    Returns instance of class.

  "query"
     my $ret_hr = $obj->query($sparql);

    Do SPARQL query and returns result.

    Returns reference to hash with result.

  "query_count"
     my $count = $obj->query_count($sparql_count);

    Get count value for $sparql_count SPARQL query.

    Returns number.

ERRORS
     new():
             From Class::Utils::set_params():
                     Unknown parameter '%s'.
             Parameter 'lwp_user_agent' must be a 'LWP::UserAgent' instance.

EXAMPLE1
     use strict;
     use warnings;

     use Data::Printer;
     use WQS::SPARQL;
     use WQS::SPARQL::Query::Count;

     if (@ARGV < 1) {
             print STDERR "Usage: $0 ccnb\n";
             exit 1;
     }
     my $ccnb = $ARGV[0];

     my $q = WQS::SPARQL->new;
     my $sparql = WQS::SPARQL::Query::Count->new->count_simple('P3184',
             $ccnb);
     my $ret_hr = $q->query($sparql);

     # Dump structure to output.
     p $ret_hr;
 
     # Output for cnb002826100:
     # \ {
     #     head      {
     #         vars   [
     #             [0] "count"
     #         ]
     #     },
     #     results   {
     #         bindings   [
     #             [0] {
     #                 count   {
     #                     datatype   "http://www.w3.org/2001/XMLSchema#integer",
     #                     type       "literal",
     #                     value      1
     #                 }
     #             }
     #         ]
     #     }
     # }

EXAMPLE2
     use strict;
     use warnings;

     use WQS::SPARQL;
     use WQS::SPARQL::Query::Count;

     if (@ARGV < 1) {
             print STDERR "Usage: $0 ccnb\n";
             exit 1;
     }
     my $ccnb = $ARGV[0];

     my $q = WQS::SPARQL->new;
     my $sparql = WQS::SPARQL::Query::Count->new->count_simple('P3184',
             $ccnb);
     my $ret = $q->query_count($sparql);

     # Print count.
     print "Count: $ret\n";
 
     # Output for 'cnb002826100':
     # Count: 1

     # Output for 'bad':
     # Count: 0

DEPENDENCIES
    Class::Utils, Error::Pure. HTTP::Request, JSON::XS, LWP::UserAgent, URI,
    URI::QueryParam, Unicode::UTF8.

SEE ALSO
    WQS::SPARQL::Query
        Usefull Wikdata Query Service SPARQL queries.

REPOSITORY
    <https://github.com/michal-josef-spacek/WQS-SPARQL>

AUTHOR
    Michal Josef Špaček <mailto:skim@cpan.org>

    <http://skim.cz>

LICENSE AND COPYRIGHT
    © Michal Josef Špaček 2020-2023

    BSD 2-Clause License

VERSION
    0.02

