Quadcap Embeddable Server

com/quadcap/http/servlets/file/FileServlet.java

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package com.quadcap.http.servlets.file;

/* Copyright 1998 - 2003 Quadcap Software.  All rights reserved.
 *
 * This software is distributed under the Quadcap Free Software License.
 * This software may be used or modified for any purpose, personal or
 * commercial.  Open Source redistributions are permitted.  Commercial
 * redistribution of larger works derived from, or works which bundle
 * this software requires a "Commercial Redistribution License"; see
 * http://www.quadcap.com/purchase.
 *
 * Redistributions qualify as "Open Source" under  one of the following terms:
 *   
 *    Redistributions are made at no charge beyond the reasonable cost of
 *    materials and delivery.
 *
 *    Redistributions are accompanied by a copy of the Source Code or by an
 *    irrevocable offer to provide a copy of the Source Code for up to three
 *    years at the cost of materials and delivery.  Such redistributions
 *    must allow further use, modification, and redistribution of the Source
 *    Code under substantially the same terms as this license.
 *
 * Redistributions of source code must retain the copyright notices as they
 * appear in each source code file, these license terms, and the
 * disclaimer/limitation of liability set forth as paragraph 6 below.
 *
 * Redistributions in binary form must reproduce this Copyright Notice,
 * these license terms, and the disclaimer/limitation of liability set
 * forth as paragraph 6 below, in the documentation and/or other materials
 * provided with the distribution.
 *
 * The Software is provided on an "AS IS" basis.  No warranty is
 * provided that the Software is free of defects, or fit for a
 * particular purpose.  
 *
 * Limitation of Liability. Quadcap Software shall not be liable
 * for any damages suffered by the Licensee or any third party resulting
 * from use of the Software.
 */

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;

import java.util.Enumeration;
import java.util.Hashtable;

import java.net.MalformedURLException;
import java.net.URL;

import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;

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

import com.quadcap.util.Debug;

/**
 * This class implements a generic file-serving servlet
 * <p>
 *
 * XXX This implementation is not done; it's been checked in as a work in
 * progress.
 * <p>
 *
 * @author Stan Bailes
 */

public class FileServlet extends HttpServlet {
    /** A table of mime types, indexed by file extension */
    Hashtable           mimeTypes               = new Hashtable();
    ServletContext      context;

    FileCache           files;

    /**
     * Initialize this servlet
     *
     * @param config the servlet configuration object, containing my
     *          initialization parameters
     * @exception ServletException if I can't initialize for some reason.
     */
    public void init(ServletConfig config) throws ServletException {
        super.init(config);
        context = config.getServletContext();
        String s = config.getInitParameter("cacheSize");
        if (s == null) s = "128";
        files = new FileCache(this, Integer.parseInt(s));
    }
    
    /**
     * Handle an incoming request.
     *
     * @param req HttpServletRequest that encapsulates the request to
     *          the servlet 
     * @param res HttpServletResponse that encapsulates the response
     *          from the servlet
     * 
     * @exception IOException if detected when handling the request
     * @exception ServletException if the request could not be handled
     */
    protected void service(HttpServletRequest req, HttpServletResponse res)
        throws ServletException, IOException
    {
        try {
            HttpFile file = getFileForRequest(req);
            if (file == null) {
                res.sendError(HttpServletResponse.SC_NOT_FOUND,
                              "Not Found");
            } else {
                try {
                    file.service(req, res);
                } catch (FileNotFoundException ex) {
                    res.sendError(HttpServletResponse.SC_NOT_FOUND,
                                  "Not Found");
                }
                
            }
        } catch (FileNotFoundException f3) {
            res.sendError(HttpServletResponse.SC_NOT_FOUND,
                          "Not Found");
        } catch (Exception e) {
            Debug.print(e);
            res.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
                           e.toString());
        }
    }

    /**
     * Return a file object which is suitable for processing the specified
     * request. 
     *
     * @param req the http request to service.
     * @return the file, or null if the file doesn't exist.
     *
     * @exception Exception may be thrown.
     */
    public HttpFile getFileForRequest(HttpServletRequest req)
        throws Exception
    {
        HttpFile f = null;
        String path = req.getServletPath();
        String p = req.getPathInfo();
        if (p != null) path = path + p;
        String real = context.getRealPath(path);
        if (real != null) {
            f = (HttpFile)files.get(real);  // Get the file from the cache
            if (f != null) {
                f.checkModified();
            }
        }
        return f;
    }

    final URL getURL(String path) throws MalformedURLException {
        return context.getResource(path);
    }

    final String getContentType(String path) {
        return context.getMimeType(path);
    }

}