sparql-client

Simple SPARQL Client for node.js

sparql-client

A simple sparql client written for Node.js (with compatibility for Apache Fuseki).

Version 0.2.0

Usage

###Querying###

 
var SparqlClient = require('sparql-client');
var util = require('util');
var endpoint = 'http://dbpedia.org/sparql';
 
// Get the leaderName(s) of the given citys 
// if you do not bind any city, it returns 10 random leaderNames 
var query = "SELECT * FROM <http://dbpedia.org> WHERE {
    ?city <http://dbpedia.org/property/leaderName> ?leaderName
} LIMIT 10";
var client = new SparqlClient(endpoint);
console.log("Query to " + endpoint);
console.log("Query: " + query);
client.query(query)
  //.bind('city', 'db:Chicago') 
  //.bind('city', 'db:Tokyo') 
  //.bind('city', 'db:Casablanca') 
  .bind('city', '<http://dbpedia.org/resource/Vienna>')
  .execute(function(errorresults) {
  process.stdout.write(util.inspect(arguments, null, 20, true)+"\n");1
});
 

###Formatting###

From version 0.2.0 it is possible to add options regarding the formating of the results. For example, we execute the following query (to retrieve all books and their genres).

PREFIX dbpedia-owl: <http://dbpedia.org/owl/>
SELECT ?book ?genre WHERE {
    ?book dbpedia-owl:literaryGenre ?genre
}

The default formatting (when no options are provided) results, for the bindings (limited to two results in our example), in

[{ book :
    {
        type: 'uri',
        value: 'http://live.dbpedia.org/page/A_Game_of_Thrones'
    },
    genre : {
        type: 'uri',
        value: 'http://live.dbpedia.org/page/Fantasy'
    }
}, { book :
    {
        type: 'uri',
        value: 'http://live.dbpedia.org/page/A_Game_of_Thrones'
    },
    genre : {
        type: 'uri',
        value: 'http://live.dbpedia.org/page/Political_strategy'
    }
}]

Using the format option resource with the resource option set to book results in

[{ book :
    {
        type: 'uri',
        value: 'http://live.dbpedia.org/page/A_Game_of_Thrones'
    },
    genre : [{
        type: 'uri',
        value: 'http://live.dbpedia.org/page/Fantasy'
    }, {
        type: 'uri',
        value: 'http://live.dbpedia.org/page/Political_strategy'
    }]
}]

This makes it easier to process the results later (in the callback), because all the genres are connected to one book (in one binding), and not spread over several bindings. Calling the execute function will look something like this

execute({format: 'resource', resource: 'book'}, function(errorresults) {
  process.stdout.write(util.inspect(arguments, null, 20, true)+"\n");
});

License

The MIT License

Copyright © 2014 Thomas Fritz

Contributors

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.