UrlRewriterCallback


1   /*
2    * Copyright (c) 1998-2006 Caucho Technology -- all rights reserved
3    *
4    * This file is part of Resin(R) Open Source
5    *
6    * Each copy or derived work must preserve the copyright notice and this
7    * notice unmodified.
8    *
9    * Resin Open Source is free software; you can redistribute it and/or modify
10   * it under the terms of the GNU General Public License as published by
11   * the Free Software Foundation; either version 2 of the License, or
12   * (at your option) any later version.
13   *
14   * Resin Open Source is distributed in the hope that it will be useful,
15   * but WITHOUT ANY WARRANTY; without even the implied warranty of
16   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
17   * of NON-INFRINGEMENT.  See the GNU General Public License for more
18   * details.
19   *
20   * You should have received a copy of the GNU General Public License
21   * along with Resin Open Source; if not, write to the
22   *
23   *   Free Software Foundation, Inc.
24   *   59 Temple Place, Suite 330
25   *   Boston, MA 02111-1307  USA
26   *
27   * @author Emil Ong
28   */
29  
30  package com.caucho.quercus.lib;
31  
32  import com.caucho.quercus.env.*;
33  import com.caucho.util.URLUtil;
34  
35  import java.lang.reflect.Method  ;
36  import java.net.URI  ;
37  import java.net.URISyntaxException  ;
38  import java.util.ArrayList  ;
39  import java.util.HashMap  ;
40  
41  /**
42   * Implements the built-in URL rewriter for passing session ids and other
43   * variables.
44   */
45  public class UrlRewriterCallback extends CallbackFunction {
46    private StringBuilder   _rewriterQuery = new StringBuilder  ();
47    private ArrayList  <String  []> _rewriterVars = new ArrayList  <String  []>();
48  
49    public UrlRewriterCallback(Env env)
50    {
51      super(env, "URL-Rewriter");
52  
53      try {
54        Method   rewriterMethod = 
55          UrlRewriterCallback.class.getMethod("_internal_url_rewriter",
56                                              Env.class, String  .class);
57        setFunction(new JavaMethod(env.getModuleContext(), rewriterMethod));
58      } catch (NoSuchMethodException   e) {
59      } catch (SecurityException   e) {
60      }
61    }
62  
63    /**
64     * Returns the unique rewriter.
65     */
66    public static UrlRewriterCallback getInstance(Env env)
67    {
68      OutputBuffer ob = env.getOutputBuffer();
69  
70      for (; ob != null; ob = ob.getNext()) {
71        Callback callback = ob.getCallback();
72  
73        if (callback instanceof UrlRewriterCallback)
74          return (UrlRewriterCallback)callback;
75      }
76  
77      return null;
78    }
79  
80    /**
81     * Adds a rewrite variable.  Intended for 
82     * <code>output_add_rewrite_var()</code>.
83     */
84    public void addRewriterVar(String   var, String   value)
85    {
86      if (_rewriterQuery.length() > 0)
87        _rewriterQuery.append("&");
88  
89      String   encodedVar = URLUtil.encodeURL(var.replaceAll(" ", "+"));
90      String   encodedValue = URLUtil.encodeURL(value.replaceAll(" ", "+"));
91  
92      _rewriterQuery.append(encodedVar + "=" + encodedValue);
93      _rewriterVars.add(new String  [] {encodedVar, encodedValue});
94    }
95  
96    /**
97     * Resets (clears) all the rewrite variables.  Intended for 
98     * <code>output_reset_rewrite_vars()</code>.
99     */
100   public void resetRewriterVars()
101   {
102     _rewriterQuery = new StringBuilder  ();
103     _rewriterVars.clear();
104   }
105   
106   /**
107    * Callback function to rewrite URLs to include session information.
108    */
109   public static Value _internal_url_rewriter(Env env, String   buffer)
110   {
111     UrlRewriterCallback rewriter = getInstance(env);
112 
113     // We should never have been called in this case, but 
114     // return the buffer unmodified anyway.
115     if (rewriter == null)
116       return NullValue.NULL;
117     
118     Parser parser = rewriter.new Parser(buffer, env);
119     return parser.parse();
120   }
121 
122   private class Parser {
123     private Env _env;
124 
125     private boolean _includeSessionInfo = false;
126     private String   _sessionName = null;
127     private String   _sessionId = null;
128     private String   _javaSessionName = null;
129     private String   _javaSessionId = null;
130 
131     private int _index;
132     private String   _value;
133     private boolean _quoted;
134 
135     private String   _input;
136     private StringBuilderValue _output = new StringBuilderValue();
137 
138     public Parser(String   input, Env env)
139     {
140       _input = input;
141       _env = env;
142       _index = 0;
143     }
144 
145     public Value parse()
146     {
147       if (_env.getSession() != null && _env.getJavaSession() != null &&
148           _env.getIni("session.use_trans_sid").toBoolean()) {
149         _includeSessionInfo = true;
150 
151         _sessionName = _env.getIni("session.name").toString();
152         _sessionId = _env.getSession().getId();
153 
154     _javaSessionName = _env.getQuercus().getCookieName();
155 
156         _javaSessionId = _env.getJavaSession().getId();
157       }
158 
159       if (_includeSessionInfo == false && _rewriterVars.isEmpty())
160         return NullValue.NULL;
161 
162       String   [] tagPairs = 
163         _env.getIni("url_rewriter.tags").toString().split(",");
164       HashMap  <String  ,String  > tags = new HashMap  <String  ,String  >();
165 
166       for (String   tagPair : tagPairs) {
167         String   [] tagAttribute = tagPair.split("=");
168 
169         switch (tagAttribute.length) {
170           case 1:
171             tags.put(tagAttribute[0], null);
172             break;
173 
174           case 2:
175             tags.put(tagAttribute[0], tagAttribute[1]);
176             break;
177 
178           default:
179             break;
180         }
181       }
182 
183       for (String   tag = getNextTag(); tag != null; tag = getNextTag()) {
184         if (tags.containsKey(tag)) {
185           String   attribute = tags.get(tag);
186           
187           if (attribute == null) {
188             consumeToEndOfTag();
189             
190             if (_includeSessionInfo) {
191               String   phpSessionInputTag = 
192                 "<input type=\"hidden\" name=\"" + _sessionName + "\"" +
193                 " value=\"" + _sessionId + "\" />";
194 
195               _output.append(phpSessionInputTag );
196             }
197 
198             for (String  [] entry : _rewriterVars) {
199               String   inputTag = 
200                 "<input type=\"hidden\" name=\"" + entry[0] + "\"" +
201                 " value=\"" + entry[1] + "\" />";
202               _output.append(inputTag);
203             }
204           } else {
205             int valueEnd = 0;
206 
207             for (valueEnd = getNextAttribute(attribute);
208                  valueEnd == 0;
209                  valueEnd = getNextAttribute(attribute))
210             {}
211 
212             if (valueEnd > 0) {
213               _output.append(rewriteUrl(_value));
214 
215               if (_quoted)
216                 consumeOneCharacter();
217             }
218           }
219         }
220       }
221 
222       return _output;
223     }
224 
225     /**
226      * Finds the next tag in the string returns it.
227      */
228     private String   getNextTag()
229     {
230       int tagStart = _input.indexOf('<', _index);
231 
232       if (tagStart < 0) {
233         _output.append(_input.substring(_index));
234         return null;
235       }
236 
237       // consume everything upto the tag opening
238       _output.append(_input.substring(_index, tagStart + 1));
239 
240       // skip the '<'
241       _index = tagStart + 1;
242       
243       consumeNonWhiteSpace();
244 
245       return _input.substring(tagStart + 1, _index);
246     }
247 
248     /**
249      * Finds the next attribute matching the given name.
250      *
251      * @return -1 if no more valid attributes can be found, 0 if the next
252      * attribute is not the one sought, and 1 if the attribute was found.  
253      *
254      * The _index pointer will refer to the end position for the value
255      * in the _input in the final case, but only those characters up to 
256      * the beginning of the value will have been copied to the output.
257      */
258     private int getNextAttribute(String   attribute)
259     {
260       consumeWhiteSpace();
261 
262       int attributeStart = _index;
263 
264       while (_index < _input.length() &&
265              isValidAttributeCharacter(_input.charAt(_index)))
266         consumeOneCharacter();
267         
268       // no valid attribute was found (we're probably at the end of the tag)
269       if (_index == attributeStart)
270         return -1;
271 
272       String   foundAttribute = _input.substring(attributeStart, _index);
273 
274       consumeWhiteSpace();
275 
276       // Any attributes that we will affect are of the form attr=value
277       if (_input.length() <= _index || _input.charAt(_index) != '=')
278         return -1;
279 
280       consumeOneCharacter();
281 
282       consumeWhiteSpace();
283 
284       // check for quoting
285       char quote = ' ';
286       
287       if (_input.charAt(_index) == '"' || _input.charAt(_index) == '\'') {
288         _quoted = true;
289         quote = _input.charAt(_index);
290 
291         consumeOneCharacter();
292       }
293 
294       int valueEnd = _index;
295       
296       if (_quoted) {
297         valueEnd = _input.indexOf(quote, _index);
298       
299         // try to account for unclosed quotes
300         int tagEnd = _input.indexOf('>', _index);
301 
302         if (valueEnd < 0) {
303           if (tagEnd > 0) 
304             valueEnd = tagEnd;
305           else
306             valueEnd = _input.length();
307         }
308       } else {
309         // skip to the end of the value
310         for (valueEnd = _index; 
311              valueEnd < _input.length() &&
312              _input.charAt(valueEnd) != '/' &&
313              _input.charAt(valueEnd) != '>' &&
314              _input.charAt(valueEnd) != ' ';
315              valueEnd++) {}
316       }
317 
318       if (foundAttribute.equals(attribute)) {
319         _value = _input.substring(_index, valueEnd);
320 
321         _index = valueEnd;
322 
323         return 1;
324       } else {
325         // make sure to skip the complete attribute if it's not the
326         // one we're looking for.
327         if (_quoted)
328           valueEnd += 1;
329 
330         _output.append(_input.substring(_index, valueEnd));
331 
332         _index = valueEnd;
333 
334         return 0;
335       }
336     }
337 
338     private void consumeOneCharacter()
339     {
340       if (_index < _input.length()) {
341         _output.append(_input.charAt(_index));
342         _index += 1;
343       }
344     }
345 
346     private void consumeWhiteSpace()
347     {
348       while (_index < _input.length() && 
349              Character.isWhitespace(_input.charAt(_index)))
350         consumeOneCharacter();
351     }
352 
353     private void consumeNonWhiteSpace()
354     {
355       while (_index < _input.length() && 
356              !Character.isWhitespace(_input.charAt(_index)))
357         consumeOneCharacter();
358     }
359 
360     private void consumeToEndOfTag()
361     {
362       while (_input.charAt(_index) != '>')
363         consumeOneCharacter();
364 
365       // consume the '>'
366       consumeOneCharacter();
367     }
368 
369     private boolean isValidAttributeCharacter(char ch)
370     {
371       return Character.isLetterOrDigit(ch) || 
372              (ch == '-') || (ch == '.') || (ch == '_') || (ch == ':');
373     }
374 
375     private String   rewriteUrl(String   urlString)
376     {
377       // according to php documentation, it only adds tags to the
378       // end of relative URLs, but according to RFC 2396, any
379       // URI beginning with '/' (e.g. <a HREF="../../../../../foo">link</a>) is
380       // absolute.  Nonetheless, php does add session ids to these
381       // links.  Thus php must be defining "relative" as relative
382       // to the host, not the hierarchy.  Thus we only check to make
383       // sure that the scheme and authority are undefined, not that
384       // the first character of the path begins with '/'.
385 
386       URI   uri;
387 
388       try {
389         uri = new URI  (urlString);
390       } catch (URISyntaxException   e) {
391         return urlString;
392       }
393 
394       if ((uri.getScheme() != null) || (uri.getAuthority() != null)) {
395         return urlString;
396       }
397 
398       StringBuilder   query = new StringBuilder  ();
399 
400       if (uri.getQuery() != null) {
401         query.append("?");
402         query.append(uri.getQuery());
403         query.append("&");
404       } 
405       else
406         query.append("?");
407 
408       if (_includeSessionInfo) {
409         query.append(_sessionName);
410         query.append("=");
411         query.append(_sessionId);
412       }
413 
414       if (_rewriterQuery.length() != 0) {
415         if (_includeSessionInfo)
416           query.append("&");
417 
418         query.append(_rewriterQuery);
419       }
420 
421       StringBuilder   newUri = new StringBuilder  ();
422 
423       if (uri.getPath() != null)
424         newUri.append(uri.getPath());
425 
426       newUri.append(query);
427 
428       if (uri.getFragment() != null) {
429         newUri.append("#");
430         newUri.append(uri.getFragment());
431       }
432 
433       return newUri.toString();
434     }
435   }
436 }
437
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