SampleUploadServlet.java

/*
 * Copyright 2010 Manuel Carrasco Moñino. (manolo at apache/org)
 * http://code.google.com/p/gwtupload
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package gwtuploadsample.server;

import static gwtupload.shared.UConsts.*;
import gwtupload.server.UploadAction;
import gwtupload.server.exceptions.UploadActionException;

import org.apache.commons.fileupload.FileItem;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Hashtable;
import java.util.List;

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




/**
 * This is an example of how to use UploadAction class.
 *
 * This servlet saves all received files in a temporary folder,
 * and deletes them when the user sends a remove request.
 *
 * @author Manolo Carrasco Moñino
 *
 */
public class SampleUploadServlet extends UploadAction {

  private static final long serialVersionUID = 1L;

  Hashtable<String, String> receivedContentTypes = new Hashtable<String, String>();
  /**
   * Maintain a list with received files and their content types.
   */
  Hashtable<String, File> receivedFiles = new Hashtable<String, File>();

  /**
   * Override executeAction to save the received files in a custom place
   * and delete this items from session.
   */
  @Override
  public String executeAction(HttpServletRequest request, List<FileItem> sessionFiles) throws UploadActionException {
    String response = "";
    int cont = 0;
    for (FileItem item : sessionFiles) {
      if (false == item.isFormField()) {
        cont++;
        try {
          /// Create a new file based on the remote file name in the client
          // String saveName = item.getName().replaceAll("[\\\\/><\\|\\s\"'{}()\\[\\]]+", "_");
          // File file =new File("/tmp/" + saveName);

          /// Create a temporary file placed in /tmp (only works in unix)
          // File file = File.createTempFile("upload-", ".bin", new File("/tmp"));

          /// Create a temporary file placed in the default system temp folder
          File file = File.createTempFile("upload-", ".bin");
          item.write(file);

          /// Save a list with the received files
          receivedFiles.put(item.getFieldName(), file);
          receivedContentTypes.put(item.getFieldName(), item.getContentType());

          /// Compose a xml message with the full file information
          response += "<file-" + cont + "-field>" + item.getFieldName() + "</file-" + cont + "-field>\n";
          response += "<file-" + cont + "-name>" + item.getName() + "</file-" + cont + "-name>\n";
          response += "<file-" + cont + "-size>" + item.getSize() + "</file-" + cont + "-size>\n";
          response += "<file-" + cont + "-type>" + item.getContentType() + "</file-" + cont + "type>\n";
        } catch (Exception e) {
          throw new UploadActionException(e);
        }
      }
    }

    /// Remove files from session because we have a copy of them
    removeSessionFileItems(request);

    /// Send information of the received files to the client.
    return "<response>\n" + response + "</response>\n";
  }

  /**
   * Get the content of an uploaded file.
   */
  @Override
  public void getUploadedFile(HttpServletRequest request, HttpServletResponse response) throws IOException {
    String fieldName = request.getParameter(PARAM_SHOW);
    File f = receivedFiles.get(fieldName);
    if (f != null) {
      response.setContentType(receivedContentTypes.get(fieldName));
      FileInputStream is = new FileInputStream(f);
      copyFromInputStreamToOutputStream(is, response.getOutputStream());
    } else {
      super.getUploadedFile(request, response);
   }
  }

  /**
   * Remove a file when the user sends a delete request.
   */
  @Override
  public void removeItem(HttpServletRequest request, String fieldName)  throws UploadActionException {
    File file = receivedFiles.get(fieldName);
    receivedFiles.remove(fieldName);
    receivedContentTypes.remove(fieldName);
    if (file != null) {
      file.delete();
      logger.info("SAMPLE-SERVLET (" + request.getSession().getId() + ") removed file " + file.getAbsolutePath());
    }
  }
}