be.fedict.eid.dss.portal.DownloadServlet.java Source code

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Here is the source code for be.fedict.eid.dss.portal.DownloadServlet.java

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/*
 * eID Digital Signature Service Project.
 * Copyright (C) 2009 FedICT.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License version
 * 3.0 as published by the Free Software Foundation.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, see 
 * http://www.gnu.org/licenses/.
 */

package be.fedict.eid.dss.portal;

import java.io.IOException;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class DownloadServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;

    private static final Log LOG = LogFactory.getLog(DownloadServlet.class);

    private String documentSessionAttribute;

    private String contentTypeSessionAttribute;

    @Override
    public void init(ServletConfig config) throws ServletException {
        this.documentSessionAttribute = getRequiredInitParameter(config, "DocumentSessionAttribute");
        this.contentTypeSessionAttribute = getRequiredInitParameter(config, "ContentTypeSessionAttribute");
    }

    private String getRequiredInitParameter(ServletConfig config, String paramName) throws ServletException {
        String paramValue = config.getInitParameter(paramName);
        if (null == paramValue) {
            throw new ServletException("missing init-param: " + paramName);
        }
        return paramValue;
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        LOG.debug("doGet");
        HttpSession httpSession = request.getSession();
        byte[] document = (byte[]) httpSession.getAttribute(this.documentSessionAttribute);

        response.setHeader("Cache-Control", "no-cache, no-store, must-revalidate, max-age=-1"); // http 1.1
        if (false == request.getScheme().equals("https")) {
            // else the download fails in IE
            response.setHeader("Pragma", "no-cache"); // http 1.0
        } else {
            response.setHeader("Pragma", "public");
        }
        response.setDateHeader("Expires", -1);
        response.setContentLength(document.length);

        String contentType = (String) httpSession.getAttribute(this.contentTypeSessionAttribute);
        LOG.debug("content-type: " + contentType);
        response.setContentType(contentType);
        response.setContentLength(document.length);
        ServletOutputStream out = response.getOutputStream();
        out.write(document);
        out.flush();
    }
}