HttpSparqlEndpoint.java

package org.aksw.sparqlify.web;


import javax.annotation.Resource;
import javax.servlet.ServletContext;
import javax.ws.rs.Consumes;
import javax.ws.rs.FormParam;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.StreamingOutput;

import org.aksw.jena_sparql_api.core.QueryExecutionFactory;
import org.aksw.jena_sparql_api.utils.SparqlFormatterUtils;
import org.aksw.sparqlify.core.sparql.QueryExecutionFactoryEx;
import org.apache.jena.riot.WebContent;
import org.springframework.stereotype.Component;


/**
 * Jersey resource for exposing a SparqlEndpoint based on a QueryExecutionFactory
 *
 * @author Claus Stadler <cstadler@informatik.uni-leipzig.de>
 *
 */
@Component
@Path("/sparql")
public class HttpSparqlEndpoint {

    //@Context
    //@Resource(mappedName="java:/sparqlifyDS")
    //@Context
    //@Autowired
    @Resource
    private QueryExecutionFactoryEx queryExecutionFactory;
    //private DataSource dataSource;


    public void setQueryExecutionFactory(QueryExecutionFactoryEx queryExecutionFactory) {
        this.queryExecutionFactory = queryExecutionFactory;
    }

    public QueryExecutionFactory getQueryExecutionFactorys() {
        return queryExecutionFactory;
    }

    //@Context
    //protected QueryExecutionFactory<QueryExecutionStreaming> sparqler = null;
    public static QueryExecutionFactoryEx sparqler = null;


    // No-arg constructor
    // used for injecting the QueryExecutionFactory via Spring
    public HttpSparqlEndpoint() {

    }

    public HttpSparqlEndpoint(@Context ServletContext context) {
        QueryExecutionFactoryEx qef = (QueryExecutionFactoryEx)context.getAttribute("queryExecutionFactory");

        this.queryExecutionFactory = qef;

        init();
    }


    public void init() {
    }


    public QueryExecutionFactoryEx getSparqler() throws Exception {
        if(sparqler == null) {
            sparqler = queryExecutionFactory;
        }

        if(sparqler == null) {
            throw new NullPointerException("The query execution factory has not been set.");
        }

        /*
        Connection conn = dataSource.getConnection();

        RdfViewSystemOld.loadDatatypes(conn, system.getViews());
        conn.close();

        QueryExecutionFactory<QueryExecutionStreaming> qef = new QueryExecutionFactorySparqlifyDs(system, dataSource);

        if(maxQueryExecutionTime != null) {
            qef = QueryExecutionFactoryTimeout.decorate(qef, maxQueryExecutionTime * 1000);
        }

        if(maxResultSetSize != null) {
            qef = QueryExecutionFactoryLimit.decorate(qef, false, maxResultSetSize);
        }
        */
        //System.out.println("My datasource context is " + dataSource);


        return sparqler;
    }

    public StreamingOutput processQuery(String queryString, String format)
            throws Exception
    {
        return ProcessQuery.processQuery(queryString, format, getSparqler());
    }

    /*
    @GET
    public String executeQueryXml()
            throws Exception {
        String example = "<?xml version='1.0' encoding='ISO-8859-1'?><xml>Select * { ?s ?p ?o } Limit 10</xml>";
        return "No query specified. Example: ?query=" + StringUtils.urlEncode(example);
    }
    */

    /*
    @GET
    @Produces(MediaType.TEXT_PLAIN)
    public String executeQuery()
            throws Exception {
        return "No query specified";
    }
    */


    /*
    @GET
    public StreamingOutput executeQueryXml(@QueryParam("query") String queryString)
            throws Exception {
        return processQuery(queryString, SparqlFormatterUtils.FORMAT_XML);
    }
    */


    //@Consumes(MediaType.APPLICATION_FORM_URLENCODED)
    @GET
    @Produces(MediaType.APPLICATION_XML)
    public StreamingOutput executeQueryXml(@QueryParam("query") String queryString)
            throws Exception {

        if(queryString == null) {
            return StreamingOutputString.create("<error>No query specified. Append '?query=<your SPARQL query>'</error>");
        }

        return processQuery(queryString, SparqlFormatterUtils.FORMAT_XML);
    }

    //@Produces(MediaType.APPLICATION_XML)
    @POST
    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
    public StreamingOutput executeQueryXmlPost(@FormParam("query") String queryString)
            throws Exception {

        if(queryString == null) {
            return StreamingOutputString.create("<error>No query specified. Append '?query=<your SPARQL query>'</error>");
        }

        return processQuery(queryString, SparqlFormatterUtils.FORMAT_XML);
    }

    @GET
    @Produces({MediaType.APPLICATION_JSON, "application/sparql-results+json"})
    public StreamingOutput executeQueryJson(@QueryParam("query") String queryString)
            throws Exception {
        return processQuery(queryString, SparqlFormatterUtils.FORMAT_Json);
    }

    @POST
    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
    @Produces({MediaType.APPLICATION_JSON, "application/sparql-results+json"})
    public StreamingOutput executeQueryJsonPost(@FormParam("query") String queryString)
            throws Exception {
        return processQuery(queryString, SparqlFormatterUtils.FORMAT_Json);
    }

    //@Produces("application/rdf+xml")
    //@Consumes(MediaType.APPLICATION_FORM_URLENCODED)
    @GET
    @Produces(WebContent.contentTypeRDFXML)
    public StreamingOutput executeQueryRdfXml(@QueryParam("query") String queryString)
            throws Exception {
        return processQuery(queryString, SparqlFormatterUtils.FORMAT_RdfXml);
    }


    @POST
    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
    @Produces(WebContent.contentTypeRDFXML)
    public StreamingOutput executeQueryRdfXmlPost(@FormParam("query") String queryString)
            throws Exception {
        return processQuery(queryString, SparqlFormatterUtils.FORMAT_RdfXml);
    }

    @GET
    @Produces("application/sparql-results+xml")
    public StreamingOutput executeQueryResultSetXml(@QueryParam("query") String queryString)
            throws Exception {
        return processQuery(queryString, SparqlFormatterUtils.FORMAT_XML);
    }

    @POST
    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
    @Produces("application/sparql-results+xml")
    public StreamingOutput executeQueryResultSetXmlPost(@FormParam("query") String queryString)
            throws Exception {
        return processQuery(queryString, SparqlFormatterUtils.FORMAT_XML);
    }

    @GET
    @Produces(MediaType.TEXT_PLAIN)
    public StreamingOutput executeQueryText(@QueryParam("query") String queryString)
            throws Exception {
        return processQuery(queryString, SparqlFormatterUtils.FORMAT_Text);
    }

    @POST
    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
    @Produces(MediaType.TEXT_PLAIN)
    public StreamingOutput executeQueryTextPost(@FormParam("query") String queryString)
            throws Exception {
        return processQuery(queryString, SparqlFormatterUtils.FORMAT_Text);
    }



    /*
    private String _corsHeaders;

    private Response makeCORS(ResponseBuilder req, String returnMethod) {
       Response rb = req.ok()
          .header("Access-Control-Allow-Origin", "*")
          .header("Access-Control-Allow-Methods", "GET, POST, OPTIONS");

       if (!"".equals(returnMethod)) {
          rb.header("Access-Control-Allow-Headers", returnMethod);
       }

       return rb.build();
    }

    private Response makeCORS(ResponseBuilder req) {
       return makeCORS(req, _corsHeaders);
    }
    */


    /*
    @GET
    public Response executeQueryXml(@Context HttpContext hc, @QueryParam("query") String queryString, @QueryParam("format") String format)
            throws Exception {

        hc.getResponse().getHttpHeaders().put("Content-Type", SparqlFormatterUtils.FORMAT_Json);

        if(queryString == null) {
            hc.getResponse().getOutputStream()
            return StreamingOutputString.create("<error>No query specified. Append '?query=<your SPARQL query>'</error>");
        }

        if(format != null) {
            return processQuery(queryString, SparqlFormatterUtils.FORMAT_Json);
        }

        return processQuery(queryString, SparqlFormatterUtils.FORMAT_XML);
    }
    */

}