ServletUtils.java

/*
 * Copyright 2014-2016 CyberVision, Inc.
 *
 * 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 org.kaaproject.kaa.server.admin.servlet;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.UnsupportedEncodingException;

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

public class ServletUtils {

  private static final Logger LOG = LoggerFactory.getLogger(ServletUtils.class);

  private ServletUtils() {
  }

  /**
   * Prepare disposition.
   *
   * @param request   the http servlet request
   * @param response  the http servlet response
   * @param fileName  the name of the file
   */
  public static void prepareDisposition(HttpServletRequest request, HttpServletResponse response,
                                        String fileName) {
    String userAgent = request.getHeader("user-agent");
    boolean isInternetExplorer = userAgent.contains("MSIE");

    try {
      byte[] fileNameBytes = fileName.getBytes(isInternetExplorer ? "windows-1250" : "utf-8");
      String dispositionFileName = "";
      for (byte b : fileNameBytes) {
        dispositionFileName += (char) (b & 0xff);
      }

      String disposition = "attachment; filename=\"" + dispositionFileName + "\"";
      response.setHeader("Content-Disposition", disposition);
    } catch (UnsupportedEncodingException ence) {
      LOG.error("Exception catched: ", ence);
    }
  }
}