com.clustercontrol.client.ui.util.FileDownloader.java Source code

Introduction

Here is the source code for com.clustercontrol.client.ui.util.FileDownloader.java

Source

/**********************************************************************
 * Copyright (C) 2006 NTT DATA Corporation
 * 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, version 2.
 * 
 * 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.
 *********************************************************************/

package com.clustercontrol.client.ui.util;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;
import java.net.URLEncoder;

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

import org.apache.log4j.Logger;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.rap.rwt.RWT;
import org.eclipse.rap.rwt.service.ServiceHandler;
import org.eclipse.swt.SWT;
import org.eclipse.swt.browser.Browser;
import org.eclipse.swt.widgets.Composite;

import com.clustercontrol.util.Messages;

/**
 * File download with Browser widget
 * 
 * @version 5.0.0
 * @since 5.0.0
 */
public class FileDownloader {
    public final static String DOWNLOAD_HANDLER = "filedownload";
    public final static String FILE_KEY = "dl";
    public final static String FILENAME_PARAM = "dl";
    public static boolean handlerRegistered = false;
    public static int BUFFER_SIZE = 1024 * 32;

    /**
     * DownloadService handler
     * 
     * One-time download.
     */
    private static void registerDownloadHandler() {
        if (!handlerRegistered) {
            try {
                RWT.getServiceManager().registerServiceHandler(DOWNLOAD_HANDLER, new ServiceHandler() {
                    @Override
                    public void service(HttpServletRequest request, HttpServletResponse response)
                            throws IOException, ServletException {
                        // Send the file
                        outputStream(response, request.getParameter(FILENAME_PARAM));
                    }

                    private void outputStream(HttpServletResponse response, String filename)
                            throws ServletException, IOException {
                        OutputStream outStream = response.getOutputStream();
                        File file = (File) RWT.getUISession().getAttribute(filename);
                        try {
                            FileInputStream fileStream = new FileInputStream(file);
                            BufferedInputStream bufferedStream = new BufferedInputStream(fileStream);

                            // Response header
                            response.setContentType("application/octet-stream");
                            response.setContentLength((int) file.length());
                            response.setHeader("Content-Disposition",
                                    "attachment; filename*=UTF-8''" + URLEncoder.encode(filename, "UTF-8"));

                            int len = 0;
                            byte[] buffer = new byte[FileDownloader.BUFFER_SIZE];
                            while ((len = bufferedStream.read(buffer)) >= 0) {
                                outStream.write(buffer, 0, len);
                            }
                            bufferedStream.close();
                        } catch (FileNotFoundException e) {
                            printOutNotFound(response, HttpServletResponse.SC_NOT_FOUND, "Not Found");
                        } catch (IOException e) {
                            printOutNotFound(response, HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
                                    "Internal Server Error");
                        } finally {
                            if (outStream != null) {
                                try {
                                    outStream.close();
                                } catch (IOException e) {
                                } finally {
                                    outStream = null;
                                }
                            }
                        }
                    }

                    private void printOutNotFound(HttpServletResponse response, int sc, String msg)
                            throws IOException {
                        response.setStatus(sc);
                        response.sendError(sc, msg);
                    }
                });
                handlerRegistered = true;
            } catch (IllegalArgumentException e) {
            }
        }
    }

    /**
     * Generate download URL
     * 
     * @return URL
     */
    private static String generateUrl(String filename, File tmpFile) {
        final StringBuilder url = new StringBuilder();
        url.append(RWT.getServiceManager().getServiceHandlerUrl(DOWNLOAD_HANDLER));
        url.append("&").append(FILENAME_PARAM).append("=");
        url.append(filename);
        RWT.getUISession().setAttribute(filename, tmpFile);

        url.append("&nocache=").append(System.currentTimeMillis());

        return RWT.getResponse().encodeURL(url.toString());
    }

    public static boolean openBrowser(Composite parent, String path, String filename) {
        // Register download handler at first
        registerDownloadHandler();

        // Browser for sending file
        Browser browser = new Browser(parent, SWT.NONE);
        browser.setSize(0, 0);

        File tmpFile = null;
        tmpFile = new File(path);
        tmpFile.deleteOnExit();
        // Start download
        if (browser.setUrl(generateUrl(filename, tmpFile))) {
            MessageDialog.openInformation(parent.getShell(), Messages.getString("download"),
                    Messages.getString("download.message", new String[] { filename }));
            return true;
        }
        return false;
    }

    /**
     * Delete the temporary file on server-side
     * 
     * @return URL
     */
    public static void cleanup(String path) {
        File tmpFile = new File(path);

        // Delete temporary file
        if (null != tmpFile && tmpFile.exists()) {
            if (!tmpFile.delete()) {
                Logger.getLogger(FileDownloader.class).debug("Fial to delete file. " + tmpFile.getAbsolutePath());
            }
        }
    }

}