ContentDownload.java

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/*
 * Turró i Cutiller Foundation. License notice.
 * Copyright (C) 2020 Lluis Turró Cutiller <http://www.turro.org/>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
package org.turro.elephant.download;
 
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.function.Predicate;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.activation.MimetypesFileTypeMap;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.amic.util.string.Cipher;
import org.apache.commons.io.IOUtils;
import org.turro.elephant.context.ElephantContext;
import org.turro.elephant.context.IConstructor;
import org.turro.elephant.direct.DirectContent;
import org.turro.elephant.direct.DirectContents;
import org.turro.elephant.direct.IDirectContent;
import org.turro.log.SystemLogger;
import org.turro.util.IdGenerator;
 
@DirectContent(identifier="content-download")
public class ContentDownload implements IDirectContent {
  
  private static final String CONTENT_DOWNLOAD_KEY = "contentDownKeys";
  public static final MimetypesFileTypeMap MIME_TYPES_FILE_MAP = new MimetypesFileTypeMap();
 
  public static String createURL(IConstructor constructor, ContentStream onDownload) {
    Map<String, ContentStream> downKeys = (Map<String, ContentStream>) constructor.getSessionAttribute(CONTENT_DOWNLOAD_KEY);
    if(downKeys == null) {
      downKeys = new HashMap<>();
    }
    String key = Cipher.digest(IdGenerator.generateHex() + "", 40);
    downKeys.put(key, onDownload);
    constructor.setSessionAttribute(CONTENT_DOWNLOAD_KEY, downKeys);
    return ElephantContext.getRootWebPath() + DirectContents.DIRECT_CONTENT_PATH + getIdentifier() + "?id=" + key;
  }
 
  public static String getIdentifier() {
    return ContentDownload.class.getAnnotation(DirectContent.class).identifier();
  }
 
  @Override
  public boolean itsMe(String id) {
    return getIdentifier().equals(id);
  }
 
  @Override
  public boolean myTurn(HttpServletRequest request) {
    return DirectContents.isYourTurn(request, getIdentifier());
  }
 
  @Override
  public void execute(ServletContext context, HttpServletRequest request, HttpServletResponse response) {
    Map<String, Predicate<ContentStream>> downKeys = (Map<String, Predicate<ContentStream>>) request.getSession().getAttribute(CONTENT_DOWNLOAD_KEY);
    if(downKeys != null) {
      ContentStream onDownload = (ContentStream) downKeys.get(request.getParameter("id"));
      if(onDownload != null) {
        try {
          String fileName = onDownload.getFileName();
          String contentType = MIME_TYPES_FILE_MAP.getContentType(fileName);
 
          response.setHeader("pragma", "no-cache");
          response.setHeader("Cache-control", "no-cache, no-store, must-revalidate");
          response.setHeader("Expires", "01 Apr 1995 01:10:10 GMT");
 
          if(contentType!=null) {
            response.setContentType(contentType);
          }
 
          if(fileName != null) {
            fileName = fileName.substring(fileName.lastIndexOf('\\')+1);
            fileName = fileName.substring(fileName.lastIndexOf('/')+1);
 
            StringBuilder contentDisposition = new StringBuilder();
 
            contentDisposition.append("filename=\"");
            contentDisposition.append(fileName);
            contentDisposition.append("\"");
 
            response.setHeader("Content-Disposition", contentDisposition.toString());
            response.setHeader("Content-Lenght", onDownload.getFileSize() + "");
          }
 
          IOUtils.copy(onDownload.getInputStream(), response.getOutputStream());
 
          SystemLogger.info()
                  .entityPath("/file" + ElephantContext.getRelativePath(onDownload.getAbsolutePath()))
                  .entityName(fileName).comment("downloaded")
                  .log();
        } catch (IOException ex) {
          Logger.getLogger(ContentDownload.class.getName()).log(Level.SEVERE, ElephantContext.logMsg(null), ex);
        }
      }
    }
  }
  
}