JnlpDownloadServlet.java

/*
 * @(#)JnlpDownloadServlet.java	1.10 07/03/15
 * 
 * Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * -Redistribution of source code must retain the above copyright notice, this
 *  list of conditions and the following disclaimer.
 *
 * -Redistribution 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 Sun Microsystems, Inc. or the names of contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
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 *
 * You acknowledge that this software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of any
 * nuclear facility.
 */

package jnlp.sample.servlet;

import java.io.*;
import java.util.*;
import java.net.*;
import javax.servlet.*;
import javax.servlet.http.*;

/**
 * This Servlet class is an implementation of JNLP Specification's
 * Download Protocols.
 *
 * All requests to this servlet is in the form of HTTP GET commands.
 * The parameters that are needed are:
 * <ul>
 * <li><code>arch</code>,
 * <li><code>os</code>,
 * <li><code>locale</code>,
 * <li><code>version-id</code> or <code>platform-version-id</code>,
 * <li><code>current-version-id</code>,
 * <li>code>known-platforms</code>
 * </ul>
 * <p>
 *
 * @version 1.8 01/23/03
 */
public class JnlpDownloadServlet extends HttpServlet {
    
    // Localization
    private static ResourceBundle  _resourceBundle = null; 
    
    // Servlet configuration
    private static final String PARAM_JNLP_EXTENSION    = "jnlp-extension";    
    private static final String PARAM_JAR_EXTENSION     = "jar-extension";    
    
    // Servlet configuration
    private Logger _log = null;
    
    private JnlpFileHandler _jnlpFileHandler = null;
    private JarDiffHandler  _jarDiffHandler = null;
    private ResourceCatalog _resourceCatalog = null;    
    
    /** Initialize servlet */
    public void init(ServletConfig config) throws ServletException {
        super.init(config);
	
	
	// Setup logging
	_log = new Logger(config, getResourceBundle());
	_log.addDebug("Initializing");
	
	// Get extension from Servlet configuration, or use default	
	JnlpResource.setDefaultExtensions(
	    config.getInitParameter(PARAM_JNLP_EXTENSION), 
	    config.getInitParameter(PARAM_JAR_EXTENSION));		
	
	_jnlpFileHandler = new JnlpFileHandler(config.getServletContext(), _log);
	_jarDiffHandler = new JarDiffHandler(config.getServletContext(), _log);
	_resourceCatalog = new ResourceCatalog(config.getServletContext(), _log);		
    }
    
    public static synchronized ResourceBundle getResourceBundle() {
	if (_resourceBundle == null) {
	    _resourceBundle = ResourceBundle.getBundle("jnlp/sample/servlet/resources/strings");
	}
	return _resourceBundle;
    }
    
    
    public void doHead(HttpServletRequest request, HttpServletResponse response) 
        throws ServletException, IOException {
        handleRequest(request, response, true);
    }
    
    /** We handle get requests too - eventhough the spec. only requeres POST requests */
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        handleRequest(request, response, false);
    }
    
    private void handleRequest(HttpServletRequest request, 
            HttpServletResponse response, boolean isHead) throws IOException {
	String requestStr = request.getRequestURI();
	if (request.getQueryString() != null) requestStr += "?" + request.getQueryString().trim();
	
	// Parse HTTP request
	DownloadRequest dreq = new DownloadRequest(getServletContext(), request);		
	if (_log.isInformationalLevel()) {
	    _log.addInformational("servlet.log.info.request",   requestStr);
	    _log.addInformational("servlet.log.info.useragent", request.getHeader("User-Agent"));	    
	}
	if (_log.isDebugLevel()) {
	    _log.addDebug(dreq.toString());
	}   
       
        long ifModifiedSince = request.getDateHeader("If-Modified-Since");

	// Check if it is a valid request
	try { 
	    // Check if the request is valid
	    validateRequest(dreq);
	    
	    // Decide what resource to return
	    JnlpResource jnlpres = locateResource(dreq);	    
	    _log.addDebug("JnlpResource: " + jnlpres);
	    
	    
	    if (_log.isInformationalLevel()) {
		_log.addInformational("servlet.log.info.goodrequest", jnlpres.getPath());		
	    }
    
            DownloadResponse dres = null;
            
            if (isHead) {   
                
                int cl = 
                      jnlpres.getResource().openConnection().getContentLength(); 
        
                // head request response
                dres = DownloadResponse.getHeadRequestResponse(
                        jnlpres.getMimeType(), jnlpres.getVersionId(),
                        jnlpres.getLastModified(), cl);               
                
            } else if (ifModifiedSince != -1 && 
                    (ifModifiedSince / 1000) >= 
                    (jnlpres.getLastModified() / 1000)) {
                // We divide the value returned by getLastModified here by 1000
                // because if protocol is HTTP, last 3 digits will always be 
                // zero.  However, if protocol is JNDI, that's not the case.
                // so we divide the value by 1000 to remove the last 3 digits
                // before comparison
                
                // return 304 not modified if possible
                _log.addDebug("return 304 Not modified");
                dres = DownloadResponse.getNotModifiedResponse();
            
            } else {
                
                // Return selected resource
                dres = constructResponse(jnlpres, dreq);
            }
            
	    dres.sendRespond(response);
	    
	} catch(ErrorResponseException ere) {
	    if (_log.isInformationalLevel()) {	    
		_log.addInformational("servlet.log.info.badrequest", requestStr);
	    }
	    if (_log.isDebugLevel()) {
		_log.addDebug("Response: "+ ere.toString());
	    }
	    // Return response from exception
	    ere.getDownloadResponse().sendRespond(response);
	} catch(Throwable e) {
	    _log.addFatal("servlet.log.fatal.internalerror", e);
	    response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
	}
    }
    
    /** Make sure that it is a valid request. This is also the place to implement the
     *  reverse IP lookup
     */
    private void validateRequest(DownloadRequest dreq) throws ErrorResponseException {
	String path = dreq.getPath();
	if (path.endsWith(ResourceCatalog.VERSION_XML_FILENAME) ||
	    path.indexOf("__") != -1 ) {
	    throw new ErrorResponseException(DownloadResponse.getNoContentResponse());	
        }
    }
    
    /** Interprets the download request and convert it into a resource that is
     *  part of the Web Archive.
     */
    private JnlpResource locateResource(DownloadRequest dreq) throws IOException, ErrorResponseException {    
	if (dreq.getVersion() == null) {	   
	    return handleBasicDownload(dreq);	
	} else {
	    return handleVersionRequest(dreq);
	}	
    }
    
    private JnlpResource handleBasicDownload(DownloadRequest dreq) throws ErrorResponseException, IOException {
	_log.addDebug("Basic Protocol lookup");
	// Do not return directory names for basic protocol
	if (dreq.getPath() == null || dreq.getPath().endsWith("/")) {
	    throw new ErrorResponseException(DownloadResponse.getNoContentResponse());
	}
	// Lookup resource	
	JnlpResource jnlpres = new JnlpResource(getServletContext(), dreq.getPath());
	if (!jnlpres.exists()) {		    
	    throw new ErrorResponseException(DownloadResponse.getNoContentResponse());
	}			
	return jnlpres;
    }        
    
    private JnlpResource handleVersionRequest(DownloadRequest dreq) throws IOException, ErrorResponseException {	
	_log.addDebug("Version-based/Extension based lookup");
	return _resourceCatalog.lookupResource(dreq);	
    }
    
    /** Given a DownloadPath and a DownloadRequest, it constructs the data stream to return
     *  to the requester
     */
    private DownloadResponse constructResponse(JnlpResource jnlpres, DownloadRequest dreq) throws IOException {
	String path = jnlpres.getPath();			
	if (jnlpres.isJnlpFile()) {	    
	    // It is a JNLP file. It need to be macro-expanded, so it is handled differently
	    boolean supportQuery = JarDiffHandler.isJavawsVersion(dreq, "1.5+");
	    _log.addDebug("SupportQuery in Href: " + supportQuery);

	    // only support query string in href for 1.5 and above
	    if (supportQuery) {
		return _jnlpFileHandler.getJnlpFileEx(jnlpres, dreq);
	    } else {
		return _jnlpFileHandler.getJnlpFile(jnlpres, dreq);
	    }
	} 
	
	// Check if a JARDiff can be returned
	if (dreq.getCurrentVersionId() != null && jnlpres.isJarFile()) {	    
	    DownloadResponse response = _jarDiffHandler.getJarDiffEntry(_resourceCatalog, dreq, jnlpres);
	    if (response != null) {
		_log.addInformational("servlet.log.info.jardiff.response");
		return response;	    
	    }
	}

	// check and see if we can use pack resource
	JnlpResource jr =  new JnlpResource(getServletContext(), 
				    jnlpres.getName(),
				    jnlpres.getVersionId(),
				    jnlpres.getOSList(),
				    jnlpres.getArchList(),
				    jnlpres.getLocaleList(),
				    jnlpres.getPath(),
				    jnlpres.getReturnVersionId(),
				    dreq.getEncoding());
	
        _log.addDebug("Real resource returned: " + jr);
	
	// Return WAR file resource
	return DownloadResponse.getFileDownloadResponse(jr.getResource(), 
							jr.getMimeType(), 
							jr.getLastModified(), 
							jr.getReturnVersionId());	    	
    }
}