package de.intevation.flys.client.server;

import java.io.OutputStream;
import java.io.IOException;

import org.w3c.dom.Document;
import org.w3c.dom.Element;

import org.apache.log4j.Logger;
import org.json.XML;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import de.intevation.artifacts.common.utils.ClientProtocolUtils;
import de.intevation.artifacts.common.utils.XMLUtils;

import de.intevation.artifacts.httpclient.http.HttpClient;
import de.intevation.artifacts.httpclient.http.HttpClientImpl;


/**
 * This service is used to request a data export from the artifact server. The
 * response is directed directly to the output stream, so that a file dialog is
 * opened.
 *
 * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
 */
public class ExportServiceImpl
extends      HttpServlet
{
    private static final Logger logger =
        Logger.getLogger(ExportServiceImpl.class);


    public void doGet(HttpServletRequest req, HttpServletResponse resp) {
        logger.info("ExportServiceImpl.doGet");

        try {
            OutputStream out = resp.getOutputStream();

            String url  = getServletContext().getInitParameter("server-url");

            String uuid      = req.getParameter("uuid");
            String mode      = req.getParameter("mode");
            String type      = req.getParameter("type");
            String locale    = req.getParameter("locale");
            String km        = req.getParameter("km");
            String fn        = mode + "." + type;

            resp.setHeader("Content-Disposition", "attachment;filename=" + fn);

            logger.debug("Request " + type + " export.");

            Document attr = null;
            if (km != null && km.length() > 0) {
                attr = XMLUtils.newDocument();
                XMLUtils.ElementCreator ec =
                        new XMLUtils.ElementCreator(attr, null, null);
                Element e = ec.create("km");
                e.setTextContent(km);
                attr.appendChild(e);
            }
            Document request = ClientProtocolUtils.newOutCollectionDocument(
                uuid, mode, type, attr);
            HttpClient client = new HttpClientImpl(url, locale);
            client.collectionOut(request, uuid, mode, out);

            out.close();
            out.flush();
        }
        catch (IOException ioe) {
            logger.error(ioe, ioe);
        }
    }
}
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