htmlservlet.java

dspace 用j2ee架构的一个数字图书馆.开源程序

/*
 * HTMLServlet.java
 *
 * Version: $Revision: 1.9 $
 *
 * Date: $Date: 2005/10/18 19:48:42 $
 *
 * Copyright (c) 2002-2005, Hewlett-Packard Company and Massachusetts
 * Institute of Technology.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * - Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * - Neither the name of the Hewlett-Packard Company nor the name of the
 * Massachusetts Institute of Technology nor the names of their
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
 * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */
package org.dspace.app.webui.servlet;

import java.io.IOException;
import java.io.InputStream;
import java.net.URLDecoder;
import java.sql.SQLException;

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

import org.apache.log4j.Logger;
import org.dspace.app.webui.util.JSPManager;
import org.dspace.authorize.AuthorizeException;
import org.dspace.content.Bitstream;
import org.dspace.content.Bundle;
import org.dspace.content.Item;
import org.dspace.core.Constants;
import org.dspace.core.Context;
import org.dspace.core.LogManager;
import org.dspace.core.Utils;
import org.dspace.handle.HandleManager;

/**
 * Servlet for HTML bitstream support.
 * <P>
 * <code>/html/handle/filename</code>
 * 
 * @author Robert Tansley
 * @version $Revision: 1.9 $
 */
public class HTMLServlet extends DSpaceServlet
{
    /** log4j category */
    private static Logger log = Logger.getLogger(HTMLServlet.class);

    // Return bitstream whose name matches the target bitstream-name
    // bsName, or null if there is no match.  Match must be exact.
    // NOTE: This does not detect duplicate bitstream names, just returns first.
    private static Bitstream getItemBitstreamByName(Item item, String bsName)
    						throws SQLException
    {
        Bundle[] bundles = item.getBundles();

        for (int i = 0; i < bundles.length; i++)
        {
            Bitstream[] bitstreams = bundles[i].getBitstreams();

            for (int k = 0; k < bitstreams.length; k++)
            {
                if (bsName.equals(bitstreams[k].getName()))
                    return bitstreams[k];
            }
        }
        return null;
    }

    // On the surface it doesn't make much sense for this servlet to
    // handle POST requests, but in practice some HTML pages which
    // are actually JSP get called on with a POST, so it's needed.
    protected void doDSPost(Context context, HttpServletRequest request,
                HttpServletResponse response)
        throws ServletException, IOException, SQLException, AuthorizeException
    {
        doDSGet(context, request, response);
    }

    protected void doDSGet(Context context, HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException,
            SQLException, AuthorizeException
    {
        Bitstream bitstream = null;

        // Get the ID from the URL
        String idString = request.getPathInfo();
        String filename = "";
        String handle = "";

        if (idString != null)
        {
            // Remove leading slash
            if (idString.startsWith("/"))
            {
                idString = idString.substring(1);
            }

            // Get filename
            int slashIndex = idString.lastIndexOf('/');

            if (slashIndex != -1)
            {
                filename = idString.substring(slashIndex + 1);
                filename = URLDecoder.decode(filename,
                        Constants.DEFAULT_ENCODING);
                handle = idString.substring(0, slashIndex);
            }

            // If there's still a second slash, remove it and anything after it,
            // it might be a relative directory name
            slashIndex = handle.indexOf('/');
            slashIndex = handle.indexOf('/', slashIndex + 1);

            if (slashIndex != -1)
            {
                handle = handle.substring(0, slashIndex);
            }

            /* Get entire relative path after handle, in case it
             * is actually the bitstream name.  e.g. for item
             * with handle 1234.56/13, the URL for an item could be:
             * .../dspace/1234.56/13/sub1/sub2/foo.html
             * so return relative path: "sub1/sub2/foo.html"
             * Also translate any encoded slashes, etc. to match bitstream name.
             */
            String relPath = null;
            slashIndex = idString.indexOf('/');
            if (slashIndex != -1)
            {
                slashIndex = idString.indexOf('/', slashIndex + 1);
                if (slashIndex != -1)
                    relPath = URLDecoder.decode(idString.substring(slashIndex + 1),
                                                Constants.DEFAULT_ENCODING);
            }

            // Find the corresponding bitstream
            try
            {
                boolean found = false;

                Item item = null;

                /*
                 * If the original item doesn't have a Handle yet (because it's
                 * in the workflow) what we actually have is a fake Handle in
                 * the form: db-id/1234 where 1234 is the database ID of the
                 * item.
                 */
                if (handle.startsWith("db-id"))
                {
                    String dbIDString = handle
                            .substring(handle.indexOf('/') + 1);
                    int dbID = Integer.parseInt(dbIDString);
                    item = Item.find(context, dbID);
                }
                else
                {
                    item = (Item) HandleManager
                            .resolveToObject(context, handle);
                }

                if (item == null)
                {
                    log.info(LogManager.getHeader(context, "invalid_id",
                            "path=" + handle));
                    JSPManager
                            .showInvalidIDError(request, response, handle, -1);

                    return;
                }

                if (relPath == null ||
                    (bitstream = getItemBitstreamByName(item, relPath)) == null)
                    bitstream = getItemBitstreamByName(item, filename);

            }
            catch (NumberFormatException nfe)
            {
                // Invalid ID - this will be dealt with below
            }
        }

        // Did we get a bitstream?
        if (bitstream != null)
        {
            log.info(LogManager.getHeader(context, "view_bitstream",
                    "bitstream_id=" + bitstream.getID()));

            // Set the response MIME type
            response.setContentType(bitstream.getFormat().getMIMEType());

            // Response length
            response.setHeader("Content-Length", String.valueOf(bitstream
                    .getSize()));

            // Pipe the bits
            InputStream is = bitstream.retrieve();

            Utils.bufferedCopy(is, response.getOutputStream());
            is.close();
            response.getOutputStream().flush();
        }
        else
        {
            // No bitstream - we got an invalid ID
            log.info(LogManager.getHeader(context, "view_bitstream",
                    "invalid_bitstream_id=" + idString));

            JSPManager.showInvalidIDError(request, response, idString,
                    Constants.BITSTREAM);
        }
    }
}