JnlpDownloadServlet


1   /*
2    * @(#)JnlpDownloadServlet.java 1.10 07/03/15
3    * 
4    * Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved.
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7    * modification, are permitted provided that the following conditions are met:
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10   *  list of conditions and the following disclaimer.
11   *
12   * -Redistribution in binary form must reproduce the above copyright notice,
13   *  this list of conditions and the following disclaimer in the documentation
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16   * Neither the name of Sun Microsystems, Inc. or the names of contributors may
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22   * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
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35   */
36  
37  package jnlp.sample.servlet;
38  
39  import java.io.*;
40  import java.util.*;
41  import java.net.*;
42  import javax.servlet.*;
43  import javax.servlet.http.*;
44  
45  /**
46   * This Servlet class is an implementation of JNLP Specification's
47   * Download Protocols.
48   *
49   * All requests to this servlet is in the form of HTTP GET commands.
50   * The parameters that are needed are:
51   * <ul>
52   * <li><code>arch</code>,
53   * <li><code>os</code>,
54   * <li><code>locale</code>,
55   * <li><code>version-id</code> or <code>platform-version-id</code>,
56   * <li><code>current-version-id</code>,
57   * <li>code>known-platforms</code>
58   * </ul>
59   * <p>
60   *
61   * @version 1.8 01/23/03
62   */
63  public class JnlpDownloadServlet extends HttpServlet {
64      
65      // Localization
66      private static ResourceBundle  _resourceBundle = null; 
67      
68      // Servlet configuration
69      private static final String   PARAM_JNLP_EXTENSION    = "jnlp-extension";    
70      private static final String   PARAM_JAR_EXTENSION     = "jar-extension";    
71      
72      // Servlet configuration
73      private Logger _log = null;
74      
75      private JnlpFileHandler _jnlpFileHandler = null;
76      private JarDiffHandler  _jarDiffHandler = null;
77      private ResourceCatalog _resourceCatalog = null;    
78      
79      /** Initialize servlet */
80      public void init(ServletConfig config) throws ServletException {
81          super.init(config);
82      
83      
84      // Setup logging
85      _log = new Logger(config, getResourceBundle());
86      _log.addDebug("Initializing");
87      
88      // Get extension from Servlet configuration, or use default 
89      JnlpResource.setDefaultExtensions(
90          config.getInitParameter(PARAM_JNLP_EXTENSION), 
91          config.getInitParameter(PARAM_JAR_EXTENSION));      
92      
93      _jnlpFileHandler = new JnlpFileHandler(config.getServletContext(), _log);
94      _jarDiffHandler = new JarDiffHandler(config.getServletContext(), _log);
95      _resourceCatalog = new ResourceCatalog(config.getServletContext(), _log);       
96      }
97      
98      public static synchronized ResourceBundle getResourceBundle() {
99      if (_resourceBundle == null) {
100         _resourceBundle = ResourceBundle.getBundle("jnlp/sample/servlet/resources/strings");
101     }
102     return _resourceBundle;
103     }
104     
105     
106     public void doHead(HttpServletRequest request, HttpServletResponse response) 
107         throws ServletException, IOException {
108         handleRequest(request, response, true);
109     }
110     
111     /** We handle get requests too - eventhough the spec. only requeres POST requests */
112     public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
113         handleRequest(request, response, false);
114     }
115     
116     private void handleRequest(HttpServletRequest request, 
117             HttpServletResponse response, boolean isHead) throws IOException {
118     String   requestStr = request.getRequestURI();
119     if (request.getQueryString() != null) requestStr += "?" + request.getQueryString().trim();
120     
121     // Parse HTTP request
122     DownloadRequest dreq = new DownloadRequest(getServletContext(), request);       
123     if (_log.isInformationalLevel()) {
124         _log.addInformational("servlet.log.info.request",   requestStr);
125         _log.addInformational("servlet.log.info.useragent", request.getHeader("User-Agent"));       
126     }
127     if (_log.isDebugLevel()) {
128         _log.addDebug(dreq.toString());
129     }   
130        
131         long ifModifiedSince = request.getDateHeader("If-Modified-Since");
132 
133     // Check if it is a valid request
134     try { 
135         // Check if the request is valid
136         validateRequest(dreq);
137         
138         // Decide what resource to return
139         JnlpResource jnlpres = locateResource(dreq);        
140         _log.addDebug("JnlpResource: " + jnlpres);
141         
142         
143         if (_log.isInformationalLevel()) {
144         _log.addInformational("servlet.log.info.goodrequest", jnlpres.getPath());       
145         }
146     
147             DownloadResponse dres = null;
148             
149             if (isHead) {   
150                 
151                 int cl = 
152                       jnlpres.getResource().openConnection().getContentLength(); 
153         
154                 // head request response
155                 dres = DownloadResponse.getHeadRequestResponse(
156                         jnlpres.getMimeType(), jnlpres.getVersionId(),
157                         jnlpres.getLastModified(), cl);               
158                 
159             } else if (ifModifiedSince != -1 && 
160                     (ifModifiedSince / 1000) >= 
161                     (jnlpres.getLastModified() / 1000)) {
162                 // We divide the value returned by getLastModified here by 1000
163                 // because if protocol is HTTP, last 3 digits will always be 
164                 // zero.  However, if protocol is JNDI, that's not the case.
165                 // so we divide the value by 1000 to remove the last 3 digits
166                 // before comparison
167                 
168                 // return 304 not modified if possible
169                 _log.addDebug("return 304 Not modified");
170                 dres = DownloadResponse.getNotModifiedResponse();
171             
172             } else {
173                 
174                 // Return selected resource
175                 dres = constructResponse(jnlpres, dreq);
176             }
177             
178         dres.sendRespond(response);
179         
180     } catch(ErrorResponseException ere) {
181         if (_log.isInformationalLevel()) {      
182         _log.addInformational("servlet.log.info.badrequest", requestStr);
183         }
184         if (_log.isDebugLevel()) {
185         _log.addDebug("Response: "+ ere.toString());
186         }
187         // Return response from exception
188         ere.getDownloadResponse().sendRespond(response);
189     } catch(Throwable   e) {
190         _log.addFatal("servlet.log.fatal.internalerror", e);
191         response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
192     }
193     }
194     
195     /** Make sure that it is a valid request. This is also the place to implement the
196      *  reverse IP lookup
197      */
198     private void validateRequest(DownloadRequest dreq) throws ErrorResponseException {
199     String   path = dreq.getPath();
200     if (path.endsWith(ResourceCatalog.VERSION_XML_FILENAME) ||
201         path.indexOf("__") != -1 ) {
202         throw new ErrorResponseException(DownloadResponse.getNoContentResponse());  
203         }
204     }
205     
206     /** Interprets the download request and convert it into a resource that is
207      *  part of the Web Archive.
208      */
209     private JnlpResource locateResource(DownloadRequest dreq) throws IOException, ErrorResponseException {    
210     if (dreq.getVersion() == null) {       
211         return handleBasicDownload(dreq);   
212     } else {
213         return handleVersionRequest(dreq);
214     }   
215     }
216     
217     private JnlpResource handleBasicDownload(DownloadRequest dreq) throws ErrorResponseException, IOException {
218     _log.addDebug("Basic Protocol lookup");
219     // Do not return directory names for basic protocol
220     if (dreq.getPath() == null || dreq.getPath().endsWith("/")) {
221         throw new ErrorResponseException(DownloadResponse.getNoContentResponse());
222     }
223     // Lookup resource  
224     JnlpResource jnlpres = new JnlpResource(getServletContext(), dreq.getPath());
225     if (!jnlpres.exists()) {            
226         throw new ErrorResponseException(DownloadResponse.getNoContentResponse());
227     }           
228     return jnlpres;
229     }        
230     
231     private JnlpResource handleVersionRequest(DownloadRequest dreq) throws IOException, ErrorResponseException {    
232     _log.addDebug("Version-based/Extension based lookup");
233     return _resourceCatalog.lookupResource(dreq);   
234     }
235     
236     /** Given a DownloadPath and a DownloadRequest, it constructs the data stream to return
237      *  to the requester
238      */
239     private DownloadResponse constructResponse(JnlpResource jnlpres, DownloadRequest dreq) throws IOException {
240     String   path = jnlpres.getPath();            
241     if (jnlpres.isJnlpFile()) {     
242         // It is a JNLP file. It need to be macro-expanded, so it is handled differently
243         boolean supportQuery = JarDiffHandler.isJavawsVersion(dreq, "1.5+");
244         _log.addDebug("SupportQuery in Href: " + supportQuery);
245 
246         // only support query string in href for 1.5 and above
247         if (supportQuery) {
248         return _jnlpFileHandler.getJnlpFileEx(jnlpres, dreq);
249         } else {
250         return _jnlpFileHandler.getJnlpFile(jnlpres, dreq);
251         }
252     } 
253     
254     // Check if a JARDiff can be returned
255     if (dreq.getCurrentVersionId() != null && jnlpres.isJarFile()) {        
256         DownloadResponse response = _jarDiffHandler.getJarDiffEntry(_resourceCatalog, dreq, jnlpres);
257         if (response != null) {
258         _log.addInformational("servlet.log.info.jardiff.response");
259         return response;        
260         }
261     }
262 
263     // check and see if we can use pack resource
264     JnlpResource jr =  new JnlpResource(getServletContext(), 
265                     jnlpres.getName(),
266                     jnlpres.getVersionId(),
267                     jnlpres.getOSList(),
268                     jnlpres.getArchList(),
269                     jnlpres.getLocaleList(),
270                     jnlpres.getPath(),
271                     jnlpres.getReturnVersionId(),
272                     dreq.getEncoding());
273     
274         _log.addDebug("Real resource returned: " + jr);
275     
276     // Return WAR file resource
277     return DownloadResponse.getFileDownloadResponse(jr.getResource(), 
278                             jr.getMimeType(), 
279                             jr.getLastModified(), 
280                             jr.getReturnVersionId());           
281     }
282 }
283 
284 
285
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