Metacat

/**

 *  '$RCSfile$'

 *    Purpose: A Class that implements administrative methods 

 *  Copyright: 2008 Regents of the University of California and the

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Michael Daigle

 * 

 *   '$Author: daigle $'

 *     '$Date: 2009-06-12 16:41:43 -0700 (Fri, 12 Jun 2009) $'

 * '$Revision: 4951 $'

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

package edu.ucsb.nceas.metacat.util;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.apache.log4j.Logger;

import edu.ucsb.nceas.utilities.FileUtil;

public class ResponseUtil {

	private static Logger logMetacat = Logger.getLogger(ResponseUtil.class);

	private static int DEFAULT_BUFFER_SIZE = 4 * 1024; // 4K buffer

	/**

	 * private constructor - all methods are static so there is no

     * no need to instantiate.

	 */

	private ResponseUtil() {}

	/**

	 * Redirect a response.

	 * 

	 * @param response

	 *            that is to be redirected

	 * @param destination

	 *            the context-relative URL to which the request is forwarded

	 */

	public static void redirectResponse(HttpServletRequest request,

			HttpServletResponse response, String destination) throws MetacatUtilException {

		try {

			logMetacat.debug("Redirecting response to " + request.getContextPath() + destination);

			response.sendRedirect(request.getContextPath() + destination);

		} catch (IOException ioe) {

			throw new MetacatUtilException("I/O error when redirecting response to: " + destination);

		}

	}

	public static void writeFileToOutput(HttpServletResponse response, String fileDir, String fileName)

		throws MetacatUtilException {

		writeFileToOutput(response, fileDir, fileName, DEFAULT_BUFFER_SIZE);

	}

	public static void writeFileToOutput(HttpServletResponse response, String fileDir, String fileName, int bufferSize)

			throws MetacatUtilException {

		String filePath = "";

		try {

			filePath = fileDir + FileUtil.getFS() + fileName;

			int lastFileSep = fileName.lastIndexOf(FileUtil.getFS());

			String shortFileName = fileName.substring(lastFileSep + 1, fileName.length());

			response.setHeader("Content-Disposition", "attachment; filename=\"" + shortFileName + "\"");

			InputStream inputStream = new FileInputStream(filePath);

			OutputStream outputStream = response.getOutputStream();

			byte[] byteBuffer = new byte[bufferSize]; 

			int b = 0;

			while ((b = inputStream.read(byteBuffer)) != -1) {

				outputStream.write(byteBuffer, 0, b);

			}	

		} catch (FileNotFoundException fnfe) {

			throw new MetacatUtilException("Error finding file: " + filePath 

					+ " when writing to output");

		} catch (IOException ioe) {

			throw new MetacatUtilException("I/O Error when writing: " + filePath 

					+ "  to output");

		}

	}

}