view flys-client/src/main/java/de/intevation/flys/client/server/DistanceInfoXML.java @ 4421:0b0f415203f0

Add new Filter class to change caching Add new Filter class to avoid caching of GWT nocache files in browsers and http proxies. The new Filter class NoCacheFilter sets http headers to stop the proxies and browesers from storing the nocache files.
author Björn Ricks <bjoern.ricks@intevation.de>
date Tue, 06 Nov 2012 13:32:06 +0100
parents bc06a671ef60
children
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package de.intevation.flys.client.server;

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

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

import org.apache.log4j.Logger;

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

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

import de.intevation.artifacts.httpclient.exceptions.ConnectionException;
import de.intevation.artifacts.httpclient.http.HttpClient;
import de.intevation.artifacts.httpclient.http.HttpClientImpl;
import de.intevation.artifacts.httpclient.http.response.StreamResponseHandler;


/**
 * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
 */
public class DistanceInfoXML
extends      HttpServlet
{
    private static final Logger logger = Logger.getLogger(DistanceInfoXML.class);


    public static final String ERROR_NO_DISTANCEINFO_FOUND =
        "error_no_distanceinfo_found";


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

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

        String river  = req.getParameter("river");
        String filter = req.getParameter("filter");

        Document doc = XMLUtils.newDocument();

        XMLUtils.ElementCreator ec = new XMLUtils.ElementCreator(
            doc,
            ArtifactNamespaceContext.NAMESPACE_URI,
            ArtifactNamespaceContext.NAMESPACE_PREFIX);

        Element riverEl = ec.create("river");
        riverEl.setTextContent(river);

        doc.appendChild(riverEl);

        if (filter != null && filter.length() > 0) {
            Element typeEl = ec.create("filter");
            typeEl.setTextContent(filter);

            riverEl.appendChild(typeEl);
        }

        HttpClient client = new HttpClientImpl(url);

        try {
            InputStream in = (InputStream) client.callService(
                url, "distanceinfo", doc, new StreamResponseHandler());

            OutputStream out = resp.getOutputStream();

            byte[] b = new byte[4096];
            int i;
            while ((i = in.read(b)) >= 0) {
                out.write(b, 0, i);
            }

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