FileServlet.java

package org.jboss.seam.wiki.core.ui;

import org.jboss.seam.wiki.core.dao.WikiNodeDAO;
import org.jboss.seam.wiki.core.model.WikiUpload;
import org.jboss.seam.wiki.core.model.WikiUploadImage;
import org.jboss.seam.contexts.Contexts;
import org.jboss.seam.servlet.ContextualHttpServletRequest;
import org.apache.commons.logging.LogFactory;
import org.apache.commons.logging.Log;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

public class FileServlet extends HttpServlet {

    private static final Log log = LogFactory.getLog(FileServlet.class);

    private static final String DOWNLOAD_PATH = "/download.seam";

    private byte[] fileNotFoundImage;

    public FileServlet() {
        InputStream in = getClass().getResourceAsStream("/img/filenotfound.png");
        if (in != null) {
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            byte[] buffer = new byte[512];
            try {
                int read = in.read(buffer);
                while (read != -1) {
                    out.write(buffer, 0, read);
                    read = in.read(buffer);
                }

                fileNotFoundImage = out.toByteArray();
            }
            catch (IOException e) {
            }
        }

    }

    @Override
    protected void doGet(final HttpServletRequest request, final HttpServletResponse response)
            throws ServletException, IOException {
        new ContextualHttpServletRequest(request) {
            @Override
            public void process() throws Exception {
                doWork(request, response);
            }
        }.run();
    }

    // TODO: All data access in this method runs with auto-commit mode, see http://jira.jboss.com/jira/browse/JBSEAM-957
    protected void doWork(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        if (DOWNLOAD_PATH.equals(request.getPathInfo())) {

            String id = request.getParameter("fileId");

            Contexts.getSessionContext().set("LAST_ACCESS_ACTION", "File: " + id);

            WikiUpload file = null;

            if (!"".equals(id)) {

                Long fileId = null;
                try {
                    fileId = Long.valueOf(id);
                } catch (NumberFormatException ex) {
                    response.sendError(HttpServletResponse.SC_NOT_FOUND, "File" + id);
                }

                WikiNodeDAO wikiNodeDAO = (WikiNodeDAO)org.jboss.seam.Component.getInstance(WikiNodeDAO.class);
                file = wikiNodeDAO.findWikiUpload(fileId);
            }

            String contentType = null;
            byte[] data = null;

            String thumbnail = request.getParameter("thumbnail");

            if (file != null
                && thumbnail != null
                && Boolean.valueOf(thumbnail)
                && file.isInstance(WikiUploadImage.class)
                && ((WikiUploadImage)file).getThumbnailData() != null
                && ((WikiUploadImage)file).getThumbnailData().length >0) {

                // Render thumbnail picture
                contentType = file.getContentType();
                data = ((WikiUploadImage)file).getThumbnailData();

            } else if (file != null && file.getData() != null && file.getData().length > 0) {

                // Render file regularly
                contentType = file.getContentType();
                data = file.getData();

            } else if (fileNotFoundImage != null) {

                contentType = "image/png";
                data = fileNotFoundImage;

            }

            if (data != null) {
                response.setContentType(contentType);
                response.setContentLength(data.length);
                // If it's not a picture or if it's a picture that is an attachment, tell the browser to download
                // the file instead of displaying it
                // TODO: What about PDFs? Lot's of people want to show PDFs inline...
                if ( file != null &&
                    ( !file.isInstance(WikiUploadImage.class) || file.isAttachedToDocuments() )
                   ) {
                    response.setHeader("Content-Disposition", "attachement; filename=\"" + file.getFilename() + "\"" );
                }
                response.getOutputStream().write(data);
            }

            response.getOutputStream().flush();
        }

    }

}