FileDownloadServlet.java

package org.aplikator.server;

import javax.activation.MimeTypeParseException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLEncoder;
import java.util.logging.Logger;

import org.apache.commons.fileupload.util.Streams;
import org.apache.commons.io.IOUtils;
import org.aplikator.client.local.widgets.BinaryFieldWidget;
import org.aplikator.client.shared.data.PrimaryKey;
import org.aplikator.server.data.AplikatorServiceBackend;
import org.aplikator.server.data.BinaryData;
import org.aplikator.server.data.Context;
import org.aplikator.server.descriptor.BinaryProperty;
import org.aplikator.server.descriptor.Entity;
import org.aplikator.server.persistence.PersisterFactory;

@WebServlet(
        name = "FileDownloadServlet",
        urlPatterns = {"/download"})
public class FileDownloadServlet extends HttpServlet {
    /**
     *
     */
    private static final long serialVersionUID = 1L;

    private static final Logger LOG = Logger.getLogger(FileDownloadServlet.class.getName());

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setCharacterEncoding("UTF-8");
        String entityId = req.getParameter(BinaryFieldWidget.ENTITY_ID);
        String propertyId = req.getParameter(BinaryFieldWidget.PROPERTY_ID);
        int primaryKey = Integer.parseInt(req.getParameter(BinaryFieldWidget.PRIMARY_KEY_ID));
        int maxSize = Integer.parseInt(req.getParameter(BinaryFieldWidget.MAXSIZE_ID));
        boolean attachment = false;
        String attachmentPar = req.getParameter(BinaryFieldWidget.ATTACHMENT_ID);
        if (attachmentPar != null) {
            attachment = Boolean.parseBoolean(attachmentPar);
        }
        Entity entity = (Entity) DescriptorRegistry.get().getDescriptionItem(entityId);
        @SuppressWarnings("unchecked")
        BinaryProperty property = (BinaryProperty) DescriptorRegistry.get().getDescriptionItem(propertyId);

        BinaryData blob = PersisterFactory.getPersister().getBlob(entity, property, primaryKey, maxSize);

        if (maxSize == BinaryFieldWidget.FULL_SIZE_ATTACHMENT_CODE) {
            attachment = true;
            resp.setContentType("application/octet-stream");
        } else if (maxSize == BinaryFieldWidget.FULL_SIZE_IMAGE_CODE) {
            try {
                resp.setContentType(ImageResizer.getMimeType(blob.properties.get("filename")).toString());
            } catch (MimeTypeParseException e) {
                resp.setContentType("application/octet-stream");
            }
        } else {
            resp.setContentType("image/jpeg");
        }
        resp.setHeader("Cache-Control", "no-cache");
        resp.setHeader("Pragma", "no-cache");
        if (attachment) {
            String filename = "unnamed";
            try {
                String rawfilename = blob.properties.get("filename");
                if (property.getTriggers() != null) {
                    AplikatorServiceBackend aplikatorServiceBackend = new AplikatorServiceBackend();
                    Context ctx = new Context(req, resp, aplikatorServiceBackend, null);
                    try {
                        rawfilename = property.getTriggers().processFileName(rawfilename, new PrimaryKey(entityId, primaryKey), property, ctx);
                    } finally {
                        ctx.closeTransaction();
                    }
                }
                String encodedfilename = URLEncoder.encode(rawfilename, "UTF-8");
                filename = encodedfilename.replace("+", " ");
            } catch (Exception e) {
                LOG.warning("Error encoding filename: " + e);
            }
            resp.setHeader("Content-disposition", "attachment; filename*=UTF-8''" + filename);
        }
        if (blob.inputStream != null) {
            OutputStream os = resp.getOutputStream();

            Streams.copy(blob.inputStream, os, true);
            os.flush();
        } else if (blob.properties.isEmpty()) {
            OutputStream os = resp.getOutputStream();
            Streams.copy(IOUtils.toInputStream("EMPTY", "UTF-8"), os, true);
            os.flush();
        } else {
            resp.setContentType("image/png");
            OutputStream os = resp.getOutputStream();
            InputStream icon = this.getClass().getResourceAsStream("/genericFileIcon.png");
            Streams.copy(icon, os, true);
            os.flush();
        }
    }

}