FileDownloadHandler.java

/**
 * Copyright (C) 2012 Red Hat, Inc. and/or its affiliates.
 *
 * 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.jbpm.formModeler.core.fieldTypes.file;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.lang3.StringUtils;
import org.jbpm.formModeler.service.bb.mvc.components.handling.BeanHandler;
import org.jbpm.formModeler.service.bb.mvc.controller.CommandRequest;
import org.jbpm.formModeler.service.bb.mvc.controller.CommandResponse;
import org.jbpm.formModeler.service.bb.mvc.controller.responses.DoNothingResponse;
import org.jbpm.formModeler.service.bb.mvc.controller.responses.SendStreamResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.enterprise.context.ApplicationScoped;
import javax.inject.Inject;
import javax.inject.Named;
import java.io.File;
import java.io.FileInputStream;

/**
 * Definition a sample File Download Service, this will allow the user to download the uploaded file when pressing the download link.
 */
@Named("fdch")
@ApplicationScoped
public class FileDownloadHandler extends BeanHandler {
    private Logger log = LoggerFactory.getLogger(FileDownloadHandler.class);

    @Inject
    private FileStorageService fileStorageService;

    /**
     * Action to download the specified file
     * @param request A CommandRequest object that contains the the HttpServletRequest, HttpServletResponse, HttpSession and the information about the files uploaded on the current submit
     * @return A CommandResponse to download the file content if the file exists or an empty response if there is any error.
     */
    public CommandResponse actionDownload(CommandRequest request) {
        try {
            // try to get the content parameter that identifies the file to download and try to find the File.
            String content = request.getRequestObject().getParameter("content");
            if (!StringUtils.isEmpty(content)) {
                String path = new String(Base64.decodeBase64(content));

                // build the file, if the file exists will return and StreamResponse to download it
                File file = new File(path);
                if (file.exists()) return new SendStreamResponse(new FileInputStream(file), "inline;filename=" + file.getName());
            }
        } catch (Exception e) {
            log.warn("Error trying to get file content: ", e);
        }

        // if the file doesn't exist or something wrong happens return the DonNothingResponse
        return new DoNothingResponse();
    }
}