package de.unikiel.inf.comsys.neo4j.http;
/*
* #%L
* neo4j-sparql-extension
* %%
* Copyright (C) 2014 Niclas Hoyer
* %%
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program. If not, see
* <http://www.gnu.org/licenses/gpl-3.0.html>.
* #L%
*/
import de.unikiel.inf.comsys.neo4j.SPARQLExtensionProps;
import de.unikiel.inf.comsys.neo4j.http.streams.SPARQLBooleanStreamingOutput;
import de.unikiel.inf.comsys.neo4j.http.streams.SPARQLGraphStreamingOutput;
import de.unikiel.inf.comsys.neo4j.http.streams.SPARQLTupleStreamingOutput;
import de.unikiel.inf.comsys.neo4j.inference.QueryRewriter;
import de.unikiel.inf.comsys.neo4j.inference.QueryRewriterFactory;
import java.nio.charset.Charset;
import java.util.List;
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.WebApplicationException;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Request;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.StreamingOutput;
import javax.ws.rs.core.UriInfo;
import javax.ws.rs.core.Variant;
import org.openrdf.query.BooleanQuery;
import org.openrdf.query.GraphQuery;
import org.openrdf.query.MalformedQueryException;
import org.openrdf.query.Query;
import org.openrdf.query.QueryLanguage;
import org.openrdf.query.TupleQuery;
import org.openrdf.query.resultio.BooleanQueryResultWriterFactory;
import org.openrdf.query.resultio.TupleQueryResultWriterFactory;
import org.openrdf.query.resultio.sparqljson.SPARQLBooleanJSONWriterFactory;
import org.openrdf.query.resultio.sparqljson.SPARQLResultsJSONWriterFactory;
import org.openrdf.query.resultio.sparqlxml.SPARQLBooleanXMLWriterFactory;
import org.openrdf.query.resultio.sparqlxml.SPARQLResultsXMLWriterFactory;
import org.openrdf.query.resultio.text.BooleanTextWriterFactory;
import org.openrdf.query.resultio.text.csv.SPARQLResultsCSVWriterFactory;
import org.openrdf.query.resultio.text.tsv.SPARQLResultsTSVWriterFactory;
import org.openrdf.repository.RepositoryException;
import org.openrdf.repository.sail.SailRepository;
import org.openrdf.repository.sail.SailRepositoryConnection;
import org.openrdf.rio.RDFWriterFactory;
import org.openrdf.rio.RDFWriterRegistry;
/**
* Implementation of the "query operation" part of the SPARQL 1.1 Protocol
* standard.
*
* @see <a href="http://www.w3.org/TR/sparql11-protocol/#query-operation">
* SPARQL 1.1 Protocol
* </a>
*/
public class SPARQLQuery extends AbstractSailResource {
private final List<Variant> queryResultVariants;
private final List<Variant> booleanResultVariants;
private final QueryRewriterFactory qwfactory;
private final int timeout;
/**
* Create a new SPARQL 1.1 query resource based on a repository.
*
* @param rep the repository this resources operates on
*/
public SPARQLQuery(SailRepository rep) {
super(rep);
// initialize additional result MIME-Types
queryResultVariants = Variant.mediaTypes(
MediaType.valueOf(RDFMediaType.SPARQL_RESULTS_JSON),
MediaType.valueOf(RDFMediaType.SPARQL_RESULTS_XML),
MediaType.valueOf(RDFMediaType.SPARQL_RESULTS_CSV),
MediaType.valueOf(RDFMediaType.SPARQL_RESULTS_TSV)
).add().build();
booleanResultVariants = Variant.mediaTypes(
MediaType.valueOf(RDFMediaType.SPARQL_RESULTS_JSON),
MediaType.valueOf(RDFMediaType.SPARQL_RESULTS_XML),
MediaType.valueOf(MediaType.TEXT_PLAIN)
).add().build();
// get reference to query rewriting component
this.qwfactory = QueryRewriterFactory.getInstance(rep);
// get query timeout from properties
String sout = SPARQLExtensionProps.getProperty("query.timeout");
this.timeout = Integer.parseInt(sout);
}
/**
* Query via GET.
*
* @see <a href="http://www.w3.org/TR/sparql11-protocol/#query-operation">
* SPARQL 1.1 Protocol
* </a>
* @param req JAX-RS {@link Request} object
* @param uriInfo JAX-RS {@link UriInfo} object
* @param queryString the "query" query parameter
* @param defgraphs the "default-graph-uri" query parameter
* @param namedgraphs the "named-graph-uri" query parameter
* @param inference the "inference" query parameter
* @return the result of the SPARQL query
*/
@GET
@Produces({
RDFMediaType.SPARQL_RESULTS_JSON,
RDFMediaType.SPARQL_RESULTS_XML,
RDFMediaType.SPARQL_RESULTS_CSV,
RDFMediaType.SPARQL_RESULTS_TSV,
RDFMediaType.RDF_TURTLE,
RDFMediaType.RDF_NTRIPLES,
RDFMediaType.RDF_XML,
RDFMediaType.RDF_JSON
})
public Response query(
@Context Request req,
@Context UriInfo uriInfo,
@QueryParam("query") String queryString,
@QueryParam("default-graph-uri") List<String> defgraphs,
@QueryParam("named-graph-uri") List<String> namedgraphs,
@QueryParam("inference") String inference) {
return handleQuery(
req, uriInfo, queryString, defgraphs, namedgraphs, inference);
}
/**
* Query via URL-encoded POST.
*
* @see <a href="http://www.w3.org/TR/sparql11-protocol/#query-operation">
* SPARQL 1.1 Protocol
* </a>
* @param req JAX-RS {@link Request} object
* @param uriInfo JAX-RS {@link UriInfo} object
* @param queryString the "query" form encoded parameter
* @param defgraphs the "default-graph-uri" form encoded parameter
* @param namedgraphs the "named-graph-uri" form encoded parameter
* @param inference the "inference" form encoded parameter
* @return the result of the SPARQL query
*/
@POST
@Consumes(MediaType.APPLICATION_FORM_URLENCODED)
public Response queryPOSTEncoded(
@Context Request req,
@Context UriInfo uriInfo,
@FormParam("query") String queryString,
@FormParam("default-graph-uri") List<String> defgraphs,
@FormParam("named-graph-uri") List<String> namedgraphs,
@FormParam("inference") String inference) {
return handleQuery(
req, uriInfo, queryString, defgraphs, namedgraphs, inference);
}
/**
* Query via POST directly.
*
* @see <a href="http://www.w3.org/TR/sparql11-protocol/#query-operation">
* SPARQL 1.1 Protocol
* </a>
* @param req JAX-RS {@link Request} object
* @param uriInfo JAX-RS {@link UriInfo} object
* @param defgraphs the "default-graph-uri" form encoded parameter
* @param namedgraphs the "named-graph-uri" form encoded parameter
* @param inference the "inference" form encoded parameter
* @param queryString query as string (from HTTP request body)
* @return the result of the SPARQL query
*/
@POST
@Consumes(RDFMediaType.SPARQL_QUERY)
public Response queryPOSTDirect(
@Context Request req,
@Context UriInfo uriInfo,
@QueryParam("default-graph-uri") List<String> defgraphs,
@QueryParam("named-graph-uri") List<String> namedgraphs,
@QueryParam("inference") String inference,
String queryString) {
return handleQuery(
req, uriInfo, queryString, defgraphs, namedgraphs, inference);
}
/**
* Query via GET (with inference).
*
* @see <a href="http://www.w3.org/TR/sparql11-protocol/#query-operation">
* SPARQL 1.1 Protocol
* </a>
* @param req JAX-RS {@link Request} object
* @param uriInfo JAX-RS {@link UriInfo} object
* @param queryString the "query" query parameter
* @param defgraphs the "default-graph-uri" query parameter
* @param namedgraphs the "named-graph-uri" query parameter
* @return the result of the SPARQL query
*/
@GET
@Path("/inference")
@Produces({
RDFMediaType.SPARQL_RESULTS_JSON,
RDFMediaType.SPARQL_RESULTS_XML,
RDFMediaType.SPARQL_RESULTS_CSV,
RDFMediaType.SPARQL_RESULTS_TSV,
RDFMediaType.RDF_TURTLE,
RDFMediaType.RDF_NTRIPLES,
RDFMediaType.RDF_XML,
RDFMediaType.RDF_JSON
})
public Response queryInference(
@Context Request req,
@Context UriInfo uriInfo,
@QueryParam("query") String queryString,
@QueryParam("default-graph-uri") List<String> defgraphs,
@QueryParam("named-graph-uri") List<String> namedgraphs) {
return handleQuery(
req, uriInfo, queryString, defgraphs, namedgraphs, "true");
}
/**
* Query via URL-encoded POST (with inference).
*
* @see <a href="http://www.w3.org/TR/sparql11-protocol/#query-operation">
* SPARQL 1.1 Protocol
* </a>
* @param req JAX-RS {@link Request} object
* @param uriInfo JAX-RS {@link UriInfo} object
* @param queryString the "query" form encoded parameter
* @param defgraphs the "default-graph-uri" form encoded parameter
* @param namedgraphs the "named-graph-uri" form encoded parameter
* @return the result of the SPARQL query
*/
@POST
@Path("/inference")
@Consumes(MediaType.APPLICATION_FORM_URLENCODED)
public Response queryPOSTEncodedInference(
@Context Request req,
@Context UriInfo uriInfo,
@FormParam("query") String queryString,
@FormParam("default-graph-uri") List<String> defgraphs,
@FormParam("named-graph-uri") List<String> namedgraphs) {
return handleQuery(
req, uriInfo, queryString, defgraphs, namedgraphs, "true");
}
/**
* Query via POST directly (with inference).
*
* @see <a href="http://www.w3.org/TR/sparql11-protocol/#query-operation">
* SPARQL 1.1 Protocol
* </a>
* @param req JAX-RS {@link Request} object
* @param uriInfo JAX-RS {@link UriInfo} object
* @param defgraphs the "default-graph-uri" form encoded parameter
* @param namedgraphs the "named-graph-uri" form encoded parameter
* @param queryString query as string (from HTTP request body)
* @return the result of the SPARQL query
*/
@POST
@Path("/inference")
@Consumes(RDFMediaType.SPARQL_QUERY)
public Response queryPOSTDirectInference(
@Context Request req,
@Context UriInfo uriInfo,
@QueryParam("default-graph-uri") List<String> defgraphs,
@QueryParam("named-graph-uri") List<String> namedgraphs,
String queryString) {
return handleQuery(
req, uriInfo, queryString, defgraphs, namedgraphs, "true");
}
/**
* Implements the handling of a SPARQL query.
*
* This method accepts the different parameters for SPARQL requests,
* executes the request (with optional inference) and returns the
* result as JAX-RS HTTP response. The response will be streamed, so large
* result sets are possible.
*
* @see SPARQLTupleStreamingOutput
* @see SPARQLBooleanStreamingOutput
* @see SPARQLGraphStreamingOutput
* @param req JAX-RS {@link Request} object
* @param uriInfo JAX-RS {@link UriInfo} object
* @param queryString SPARQL query to execute
* @param defgraphs the "default-graph-uri" query parameter
* @param namedgraphs the "named-graph-uri" query parameter
* @param inference true, if the results should include inferred solutions
* @return the result of the SPARQL query
*/
private Response handleQuery(
Request req,
UriInfo uriInfo,
String queryString,
List<String> defgraphs,
List<String> namedgraphs,
String inference) {
SailRepositoryConnection conn = null;
try {
// check for empty query
if (queryString == null) {
throw new MalformedQueryException("Missing query parameter");
}
conn = getConnection();
final Query query;
// check if the query should be rewritten for inference
if (inference != null && inference.equals("true")) {
// hand over to query rewriting component
QueryRewriter qw = qwfactory.getRewriter(conn);
query = qw.rewrite(
QueryLanguage.SPARQL,
queryString,
uriInfo.getAbsolutePath().toASCIIString());
} else {
// direct preparation using Sesame repository
query = conn.prepareQuery(
QueryLanguage.SPARQL,
queryString,
uriInfo.getAbsolutePath().toASCIIString());
}
// limit query execution time
query.setMaxQueryTime(timeout);
// check query form and possible result variants
final List<Variant> acceptable;
boolean isGraphQuery = false;
boolean isBooleanQuery = false;
if (query instanceof GraphQuery) {
isGraphQuery = true;
} else if (query instanceof BooleanQuery) {
isBooleanQuery = true;
}
if (isGraphQuery) {
acceptable = rdfResultVariants;
} else if (isBooleanQuery) {
acceptable = booleanResultVariants;
} else {
acceptable = queryResultVariants;
}
final Variant variant = req.selectVariant(acceptable);
// if acceptable variants does not match "Accept" header, abort
if (variant == null) {
return Response.notAcceptable(acceptable).build();
}
final MediaType mt = variant.getMediaType();
final String mtstr = mt.getType() + "/" + mt.getSubtype();
StreamingOutput stream;
// select result writer based on query form and return streaming
// output
if (isGraphQuery) {
GraphQuery gq = (GraphQuery) query;
stream = new SPARQLGraphStreamingOutput(
gq, getRDFWriterFactory(mtstr), conn);
} else if (isBooleanQuery) {
BooleanQuery bq = (BooleanQuery) query;
stream = new SPARQLBooleanStreamingOutput(
bq, getBooleanWriterFactory(mtstr), conn);
} else {
TupleQuery tq = (TupleQuery) query;
stream = new SPARQLTupleStreamingOutput(
tq, getTupleWriterFactory(mtstr), conn);
}
return Response.ok(stream).type(mt).build();
} catch (MalformedQueryException ex) {
// syntax error
close(conn, ex);
String str = ex.getMessage();
return Response.status(Response.Status.BAD_REQUEST).entity(
str.getBytes(Charset.forName("UTF-8"))).build();
} catch (RepositoryException ex) {
// server error
close(conn, ex);
throw new WebApplicationException(ex);
}
}
/**
* Returns a {@link RDFWriterFactory} that produces RDF data according to a
* given MIME-type.
*
* @param mimetype the mimetype
* @return the corresponding writer factory
*/
private RDFWriterFactory getRDFWriterFactory(String mimetype) {
RDFWriterRegistry registry = RDFWriterRegistry.getInstance();
return registry.get(getRDFFormat(mimetype));
}
/**
* Returns a {@link TupleQueryResultWriterFactory} that returns a writer
* that writes SPARQL query results in the format of a given MIME-Type.
*
* @param mimetype the mimetype
* @return the corresponding query result writer factory
*/
private TupleQueryResultWriterFactory getTupleWriterFactory(String mimetype) {
switch (mimetype) {
default:
case RDFMediaType.SPARQL_RESULTS_JSON:
return new SPARQLResultsJSONWriterFactory();
case RDFMediaType.SPARQL_RESULTS_XML:
return new SPARQLResultsXMLWriterFactory();
case RDFMediaType.SPARQL_RESULTS_CSV:
return new SPARQLResultsCSVWriterFactory();
case RDFMediaType.SPARQL_RESULTS_TSV:
return new SPARQLResultsTSVWriterFactory();
}
}
/**
* Returns a {@link BooleanQueryResultWriterFactory} that returns a writer
* that writes SPARQL query results in the format of a given MIME-Type.
*
* @param mimetype the mimetype
* @return the corresponding query result writer factory
*/
private BooleanQueryResultWriterFactory getBooleanWriterFactory(String mimetype) {
switch (mimetype) {
default:
case RDFMediaType.SPARQL_RESULTS_JSON:
return new SPARQLBooleanJSONWriterFactory();
case RDFMediaType.SPARQL_RESULTS_XML:
return new SPARQLBooleanXMLWriterFactory();
case MediaType.TEXT_PLAIN:
return new BooleanTextWriterFactory();
}
}
}
