edu.ucla.loni.pipeline.server.Upload.Uploaders.FileUploadServlet.java Source code

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Here is the source code for edu.ucla.loni.pipeline.server.Upload.Uploaders.FileUploadServlet.java

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/*
 * This file is part of LONI Pipeline Web-based Server Terminal.
 * 
 * LONI Pipeline Web-based Server Terminal is free software: 
 * you can redistribute it and/or modify it under the terms of the 
 * GNU Lesser General Public License as published by the Free Software 
 * Foundation, either version 3 of the License, or (at your option)
 * any later version.
 *
 * LONI Pipeline Web-based Server Terminal 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 Lesser General Public License for more details.
    
 * You should have received a copy of the GNU Lesser General Public License
 * along with LONI Pipeline Web-based Server Terminal.
 * If not, see <http://www.gnu.org/licenses/>.
 */

package edu.ucla.loni.pipeline.server.Upload.Uploaders;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.apache.commons.fileupload.FileItemIterator;
import org.apache.commons.fileupload.FileItemStream;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.w3c.dom.Document;
import org.xml.sax.SAXException;

import com.google.appengine.api.datastore.Key;
import com.google.appengine.api.datastore.KeyFactory;

import edu.ucla.loni.pipeline.server.Utilities.DatastoreUtils;
import edu.ucla.loni.pipeline.server.Utilities.ResponseBuilder;

/**
 * Handles HTTP GET/POST Requests for File Upload
 */
public class FileUploadServlet extends HttpServlet {

    private static final long serialVersionUID = 5842494091385532249L;

    private final Key xmlResourceKey, xmlConfigurationKey;

    /**
     * Constructor
     */
    public FileUploadServlet() {
        xmlConfigurationKey = KeyFactory.createKey("XMLType", "ConfigurationData");
        xmlResourceKey = KeyFactory.createKey("XMLType", "ResourceData");
    }

    /**
     * Handles HTTP GET Request/Response
     * 
     * @see javax.servlet.http.HttpServlet#doGet(javax.servlet.http.HttpServletRequest,
     *      javax.servlet.http.HttpServletResponse)
     */
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doGet(req, resp);
    }

    /**
     * Handles HTTP POST Request/Response
     * 
     * @see javax.servlet.http.HttpServlet#doPost(javax.servlet.http.HttpServletRequest,
     *      javax.servlet.http.HttpServletResponse)
     */
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        // set response status
        resp.setStatus(HttpServletResponse.SC_OK);

        // reset response message
        ResponseBuilder respBuilder = new ResponseBuilder();

        // handle file upload
        handleFileUpload(req, respBuilder);

        // get response message
        String message = respBuilder.getRespMessage();

        resp.getWriter().print(message);

        // flush response buffer
        resp.flushBuffer();
    }

    /**
     * Handles Request to Upload File, Builds a Response
     * 
     * @param req
     * @param respBuilder
     */
    private void handleFileUpload(HttpServletRequest req, ResponseBuilder respBuilder) {

        // process only multipart requests
        if (ServletFileUpload.isMultipartContent(req)) {
            // Create a new file upload handler
            ServletFileUpload upload = new ServletFileUpload();

            try {
                // Parse the request
                FileItemIterator iter = upload.getItemIterator(req);

                while (iter.hasNext()) {
                    FileItemStream item = iter.next();
                    handleUploadedFile(item, respBuilder);
                }
            } catch (FileUploadException e) {
                respBuilder.appendRespMessage("The file was not uploaded successfully.");
            } catch (IOException e) {
                respBuilder.appendRespMessage("The file was not uploaded successfully.");
            }
        } else {
            respBuilder.appendRespMessage("Your form of request is not supported by this upload servlet.");
        }
    }

    /**
     * Determines XML Data type and stores file on server.
     * 
     * @param item
     * @param respBuilder
     */
    private void handleUploadedFile(FileItemStream item, ResponseBuilder respBuilder) {
        try {
            // process only file upload - discard other form item types
            if (item.isFormField()) {
                return;
            }

            // Validate
            DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
            Document document = dBuilder.parse(item.openStream());

            // Normalize
            document.getDocumentElement().normalize();

            // Determine Root Tag
            String rootTag = document.getDocumentElement().getNodeName();

            if (rootTag.equalsIgnoreCase("LONIConfigurationData")) {

                // Write to Blobstore
                DatastoreUtils.writeXMLFileToBlobStore(document, xmlConfigurationKey, respBuilder);

                // reset respBuilder (no need to have verbose messages because
                // upload was successful)
                respBuilder.resetRespMessage();

                respBuilder.appendRespMessage("LONI Configuration Data was uploaded successfully.");
            } else if (rootTag.equalsIgnoreCase("LONIResourceData")) {

                // Write to Blobstore
                DatastoreUtils.writeXMLFileToBlobStore(document, xmlResourceKey, respBuilder);

                // reset respBuilder (no need to have verbose messages because
                // upload was successful)
                respBuilder.resetRespMessage();

                respBuilder.appendRespMessage("LONI Resource Data was uploaded successfully.");
            } else {
                respBuilder.appendRespMessage("ERROR: Please upload either LONI Configuration or Resource Data.");
            }
        } catch (ParserConfigurationException e) {
            respBuilder.appendRespMessage("ERROR: File uploaded is not a valid XML file. Please try again.");
        } catch (SAXException e) {
            respBuilder.appendRespMessage("ERROR: File uploaded is not a valid XML file. Please try again.");
        } catch (IOException e) {
            respBuilder.appendRespMessage("ERROR: Could not parse file.  Please upload a text-based XML file.");
        }
    }
}