/*
 * $Id$
 *
 * This file is part of the Cloud Services Integration Platform (CSIP),
 * a Model-as-a-Service framework, API and application suite.
 *
 * 2012-2022, Olaf David and others, OMSLab, Colorado State University.
 *
 * OMSLab licenses this file to you under the MIT license.
 * See the LICENSE file in the project root for more information.
 */
package csip;

import csip.annotations.Gzip;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.GZIPOutputStream;

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

/**
 * Support for compressed responses.
 * @author od
 */
@Provider
@Gzip
public class GzipWriterInterceptor implements WriterInterceptor {

  @Override
  public void aroundWriteTo(WriterInterceptorContext context)
      throws IOException, WebApplicationException {

    MultivaluedMap<String, Object> headers = context.getHeaders();
    headers.add("Content-Encoding", "gzip");

    OutputStream outputStream = context.getOutputStream();
    context.setOutputStream(new GZIPOutputStream(outputStream));
    context.proceed();
  }
}