de.dfki.resc28.serendipity.client.RepresentationEnricher.java Source code

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Here is the source code for de.dfki.resc28.serendipity.client.RepresentationEnricher.java

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/*
 * This file is part of serendipity-client. It is subject to the license terms in
 * the LICENSE file found in the top-level directory of this distribution.
 * You may not use this file except in compliance with the License.
 */
package de.dfki.resc28.serendipity.client;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.StringReader;
import java.io.StringWriter;

import javax.ws.rs.WebApplicationException;
import javax.ws.rs.ext.Provider;
import javax.ws.rs.ext.WriterInterceptor;
import javax.ws.rs.ext.WriterInterceptorContext;

import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.jena.rdf.model.Model;
import org.apache.jena.rdf.model.ModelFactory;
import org.apache.jena.riot.Lang;
import org.apache.jena.riot.RDFDataMgr;
import org.apache.jena.riot.RDFLanguages;

import de.dfki.resc28.igraphstore.Constants;

@Provider
@GenerateAffordances
public class RepresentationEnricher implements WriterInterceptor {
    private String serendipityURI;

    public RepresentationEnricher(String serendipityURI) {
        this.serendipityURI = serendipityURI;
    }

    public void aroundWriteTo(WriterInterceptorContext context) throws IOException, WebApplicationException {
        OutputStream originalStream = context.getOutputStream();
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        context.setOutputStream(baos);

        try {
            context.proceed();
        } finally {
            // get the original responseModel
            final Model responseModel = ModelFactory.createDefaultModel();
            final String contentType = context.getMediaType().toString();
            RDFDataMgr.read(responseModel, new StringReader(baos.toString()), "",
                    RDFLanguages.contentTypeToLang(contentType));
            baos.close();

            // ask serendipity for affordances to add
            Model affordances = ModelFactory.createDefaultModel();
            StringWriter writer = new StringWriter();
            responseModel.write(writer, contentType);
            StringEntity entity = new StringEntity(writer.toString(), ContentType.create(contentType));

            CloseableHttpClient client = HttpClients.createDefault();
            HttpPost httpPost = new HttpPost(this.serendipityURI);
            httpPost.setHeader("Accept", contentType);
            httpPost.setHeader("Content-type", contentType);
            httpPost.setEntity(entity);
            CloseableHttpResponse response = client.execute(httpPost);
            //            RDFDataMgr.read(affordances, response.getEntity().getContent(), "", RDFLanguages.contentTypeToLang(response.getEntity().getContentType().getValue()));
            RDFDataMgr.read(affordances, response.getEntity().getContent(), "",
                    RDFLanguages.contentTypeToLang(contentType));
            client.close();

            // add the instantiated action to the responseModel   
            responseModel.add(affordances);

            // overwrite the response
            ByteArrayOutputStream baos2 = new ByteArrayOutputStream();
            RDFDataMgr.write(baos2, responseModel, RDFLanguages.contentTypeToLang(contentType));

            baos2.writeTo(originalStream);
            baos2.close();
            context.setOutputStream(originalStream);
        }

    }
}