001 /*
002 * Copyright 2004 The Apache Software Foundation
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016 package javax.servlet.http;
017
018 import java.text.MessageFormat;
019 import java.util.ResourceBundle;
020
021 /**
022 *
023 * Creates a cookie, a small amount of information sent by a servlet to
024 * a Web browser, saved by the browser, and later sent back to the server.
025 * A cookie's value can uniquely
026 * identify a client, so cookies are commonly used for session management.
027 *
028 * <p>A cookie has a name, a single value, and optional attributes
029 * such as a comment, path and domain qualifiers, a maximum age, and a
030 * version number. Some Web browsers have bugs in how they handle the
031 * optional attributes, so use them sparingly to improve the interoperability
032 * of your servlets.
033 *
034 * <p>The servlet sends cookies to the browser by using the
035 * {@link HttpServletResponse#addCookie} method, which adds
036 * fields to HTTP response headers to send cookies to the
037 * browser, one at a time. The browser is expected to
038 * support 20 cookies for each Web server, 300 cookies total, and
039 * may limit cookie size to 4 KB each.
040 *
041 * <p>The browser returns cookies to the servlet by adding
042 * fields to HTTP request headers. Cookies can be retrieved
043 * from a request by using the {@link HttpServletRequest#getCookies} method.
044 * Several cookies might have the same name but different path attributes.
045 *
046 * <p>Cookies affect the caching of the Web pages that use them.
047 * HTTP 1.0 does not cache pages that use cookies created with
048 * this class. This class does not support the cache control
049 * defined with HTTP 1.1.
050 *
051 * <p>This class supports both the Version 0 (by Netscape) and Version 1
052 * (by RFC 2109) cookie specifications. By default, cookies are
053 * created using Version 0 to ensure the best interoperability.
054 *
055 *
056 * @author Various
057 * @version $Version$
058 *
059 */
060
061 // XXX would implement java.io.Serializable too, but can't do that
062 // so long as sun.servlet.* must run on older JDK 1.02 JVMs which
063 // don't include that support.
064
065 public class Cookie implements Cloneable {
066
067 private static final String LSTRING_FILE =
068 "javax.servlet.http.LocalStrings";
069 private static ResourceBundle lStrings =
070 ResourceBundle.getBundle(LSTRING_FILE);
071
072 //
073 // The value of the cookie itself.
074 //
075
076 private String name; // NAME= ... "$Name" style is reserved
077 private String value; // value of NAME
078
079 //
080 // Attributes encoded in the header's cookie fields.
081 //
082
083 private String comment; // ;Comment=VALUE ... describes cookie's use
084 // ;Discard ... implied by maxAge < 0
085 private String domain; // ;Domain=VALUE ... domain that sees cookie
086 private int maxAge = -1; // ;Max-Age=VALUE ... cookies auto-expire
087 private String path; // ;Path=VALUE ... URLs that see the cookie
088 private boolean secure; // ;Secure ... e.g. use SSL
089 private int version = 0; // ;Version=1 ... means RFC 2109++ style
090
091
092
093 /**
094 * Constructs a cookie with a specified name and value.
095 *
096 * <p>The name must conform to RFC 2109. That means it can contain
097 * only ASCII alphanumeric characters and cannot contain commas,
098 * semicolons, or white space or begin with a $ character. The cookie's
099 * name cannot be changed after creation.
100 *
101 * <p>The value can be anything the server chooses to send. Its
102 * value is probably of interest only to the server. The cookie's
103 * value can be changed after creation with the
104 * <code>setValue</code> method.
105 *
106 * <p>By default, cookies are created according to the Netscape
107 * cookie specification. The version can be changed with the
108 * <code>setVersion</code> method.
109 *
110 *
111 * @param name a <code>String</code> specifying the name of the cookie
112 *
113 * @param value a <code>String</code> specifying the value of the cookie
114 *
115 * @throws IllegalArgumentException if the cookie name contains illegal characters
116 * (for example, a comma, space, or semicolon)
117 * or it is one of the tokens reserved for use
118 * by the cookie protocol
119 * @see #setValue
120 * @see #setVersion
121 *
122 */
123
124 public Cookie(String name, String value) {
125 if (!isToken(name)
126 || name.equalsIgnoreCase("Comment") // rfc2019
127 || name.equalsIgnoreCase("Discard") // 2019++
128 || name.equalsIgnoreCase("Domain")
129 || name.equalsIgnoreCase("Expires") // (old cookies)
130 || name.equalsIgnoreCase("Max-Age") // rfc2019
131 || name.equalsIgnoreCase("Path")
132 || name.equalsIgnoreCase("Secure")
133 || name.equalsIgnoreCase("Version")
134 || name.startsWith("$")
135 ) {
136 String errMsg = lStrings.getString("err.cookie_name_is_token");
137 Object[] errArgs = new Object[1];
138 errArgs[0] = name;
139 errMsg = MessageFormat.format(errMsg, errArgs);
140 throw new IllegalArgumentException(errMsg);
141 }
142
143 this.name = name;
144 this.value = value;
145 }
146
147
148
149
150
151 /**
152 *
153 * Specifies a comment that describes a cookie's purpose.
154 * The comment is useful if the browser presents the cookie
155 * to the user. Comments
156 * are not supported by Netscape Version 0 cookies.
157 *
158 * @param purpose a <code>String</code> specifying the comment
159 * to display to the user
160 *
161 * @see #getComment
162 *
163 */
164
165 public void setComment(String purpose) {
166 comment = purpose;
167 }
168
169
170
171
172 /**
173 * Returns the comment describing the purpose of this cookie, or
174 * <code>null</code> if the cookie has no comment.
175 *
176 * @return a <code>String</code> containing the comment,
177 * or <code>null</code> if none
178 *
179 * @see #setComment
180 *
181 */
182
183 public String getComment() {
184 return comment;
185 }
186
187
188
189
190
191 /**
192 *
193 * Specifies the domain within which this cookie should be presented.
194 *
195 * <p>The form of the domain name is specified by RFC 2109. A domain
196 * name begins with a dot (<code>.foo.com</code>) and means that
197 * the cookie is visible to servers in a specified Domain Name System
198 * (DNS) zone (for example, <code>www.foo.com</code>, but not
199 * <code>a.b.foo.com</code>). By default, cookies are only returned
200 * to the server that sent them.
201 *
202 *
203 * @param pattern a <code>String</code> containing the domain name
204 * within which this cookie is visible;
205 * form is according to RFC 2109
206 *
207 * @see #getDomain
208 *
209 */
210
211 public void setDomain(String pattern) {
212 domain = pattern.toLowerCase(); // IE allegedly needs this
213 }
214
215
216
217
218
219 /**
220 * Returns the domain name set for this cookie. The form of
221 * the domain name is set by RFC 2109.
222 *
223 * @return a <code>String</code> containing the domain name
224 *
225 * @see #setDomain
226 *
227 */
228
229 public String getDomain() {
230 return domain;
231 }
232
233
234
235
236 /**
237 * Sets the maximum age of the cookie in seconds.
238 *
239 * <p>A positive value indicates that the cookie will expire
240 * after that many seconds have passed. Note that the value is
241 * the <i>maximum</i> age when the cookie will expire, not the cookie's
242 * current age.
243 *
244 * <p>A negative value means
245 * that the cookie is not stored persistently and will be deleted
246 * when the Web browser exits. A zero value causes the cookie
247 * to be deleted.
248 *
249 * @param expiry an integer specifying the maximum age of the
250 * cookie in seconds; if negative, means
251 * the cookie is not stored; if zero, deletes
252 * the cookie
253 *
254 *
255 * @see #getMaxAge
256 *
257 */
258
259 public void setMaxAge(int expiry) {
260 maxAge = expiry;
261 }
262
263
264
265
266 /**
267 * Returns the maximum age of the cookie, specified in seconds,
268 * By default, <code>-1</code> indicating the cookie will persist
269 * until browser shutdown.
270 *
271 *
272 * @return an integer specifying the maximum age of the
273 * cookie in seconds; if negative, means
274 * the cookie persists until browser shutdown
275 *
276 *
277 * @see #setMaxAge
278 *
279 */
280
281 public int getMaxAge() {
282 return maxAge;
283 }
284
285
286
287
288 /**
289 * Specifies a path for the cookie
290 * to which the client should return the cookie.
291 *
292 * <p>The cookie is visible to all the pages in the directory
293 * you specify, and all the pages in that directory's subdirectories.
294 * A cookie's path must include the servlet that set the cookie,
295 * for example, <i>/catalog</i>, which makes the cookie
296 * visible to all directories on the server under <i>/catalog</i>.
297 *
298 * <p>Consult RFC 2109 (available on the Internet) for more
299 * information on setting path names for cookies.
300 *
301 *
302 * @param uri a <code>String</code> specifying a path
303 *
304 *
305 * @see #getPath
306 *
307 */
308
309 public void setPath(String uri) {
310 path = uri;
311 }
312
313
314
315
316 /**
317 * Returns the path on the server
318 * to which the browser returns this cookie. The
319 * cookie is visible to all subpaths on the server.
320 *
321 *
322 * @return a <code>String</code> specifying a path that contains
323 * a servlet name, for example, <i>/catalog</i>
324 *
325 * @see #setPath
326 *
327 */
328
329 public String getPath() {
330 return path;
331 }
332
333
334
335
336
337 /**
338 * Indicates to the browser whether the cookie should only be sent
339 * using a secure protocol, such as HTTPS or SSL.
340 *
341 * <p>The default value is <code>false</code>.
342 *
343 * @param flag if <code>true</code>, sends the cookie from the browser
344 * to the server only when using a secure protocol;
345 * if <code>false</code>, sent on any protocol
346 *
347 * @see #getSecure
348 *
349 */
350
351 public void setSecure(boolean flag) {
352 secure = flag;
353 }
354
355
356
357
358 /**
359 * Returns <code>true</code> if the browser is sending cookies
360 * only over a secure protocol, or <code>false</code> if the
361 * browser can send cookies using any protocol.
362 *
363 * @return <code>true</code> if the browser uses a secure protocol;
364 * otherwise, <code>true</code>
365 *
366 * @see #setSecure
367 *
368 */
369
370 public boolean getSecure() {
371 return secure;
372 }
373
374
375
376
377
378 /**
379 * Returns the name of the cookie. The name cannot be changed after
380 * creation.
381 *
382 * @return a <code>String</code> specifying the cookie's name
383 *
384 */
385
386 public String getName() {
387 return name;
388 }
389
390
391
392
393
394 /**
395 *
396 * Assigns a new value to a cookie after the cookie is created.
397 * If you use a binary value, you may want to use BASE64 encoding.
398 *
399 * <p>With Version 0 cookies, values should not contain white
400 * space, brackets, parentheses, equals signs, commas,
401 * double quotes, slashes, question marks, at signs, colons,
402 * and semicolons. Empty values may not behave the same way
403 * on all browsers.
404 *
405 * @param newValue a <code>String</code> specifying the new value
406 *
407 *
408 * @see #getValue
409 * @see Cookie
410 *
411 */
412
413 public void setValue(String newValue) {
414 value = newValue;
415 }
416
417
418
419
420 /**
421 * Returns the value of the cookie.
422 *
423 * @return a <code>String</code> containing the cookie's
424 * present value
425 *
426 * @see #setValue
427 * @see Cookie
428 *
429 */
430
431 public String getValue() {
432 return value;
433 }
434
435
436
437
438 /**
439 * Returns the version of the protocol this cookie complies
440 * with. Version 1 complies with RFC 2109,
441 * and version 0 complies with the original
442 * cookie specification drafted by Netscape. Cookies provided
443 * by a browser use and identify the browser's cookie version.
444 *
445 *
446 * @return 0 if the cookie complies with the
447 * original Netscape specification; 1
448 * if the cookie complies with RFC 2109
449 *
450 * @see #setVersion
451 *
452 */
453
454 public int getVersion() {
455 return version;
456 }
457
458
459
460
461 /**
462 * Sets the version of the cookie protocol this cookie complies
463 * with. Version 0 complies with the original Netscape cookie
464 * specification. Version 1 complies with RFC 2109.
465 *
466 * <p>Since RFC 2109 is still somewhat new, consider
467 * version 1 as experimental; do not use it yet on production sites.
468 *
469 *
470 * @param v 0 if the cookie should comply with
471 * the original Netscape specification;
472 * 1 if the cookie should comply with RFC 2109
473 *
474 * @see #getVersion
475 *
476 */
477
478 public void setVersion(int v) {
479 version = v;
480 }
481
482 // Note -- disabled for now to allow full Netscape compatibility
483 // from RFC 2068, token special case characters
484 //
485 // private static final String tspecials = "()<>@,;:\\\"/[]?={} \t";
486
487 private static final String tspecials = ",; ";
488
489
490
491
492 /*
493 * Tests a string and returns true if the string counts as a
494 * reserved token in the Java language.
495 *
496 * @param value the <code>String</code> to be tested
497 *
498 * @return <code>true</code> if the <code>String</code> is
499 * a reserved token; <code>false</code>
500 * if it is not
501 */
502
503 private boolean isToken(String value) {
504 int len = value.length();
505
506 for (int i = 0; i < len; i++) {
507 char c = value.charAt(i);
508
509 if (c < 0x20 || c >= 0x7f || tspecials.indexOf(c) != -1)
510 return false;
511 }
512 return true;
513 }
514
515
516
517
518
519
520 /**
521 *
522 * Overrides the standard <code>java.lang.Object.clone</code>
523 * method to return a copy of this cookie.
524 *
525 *
526 */
527
528 public Object clone() {
529 try {
530 return super.clone();
531 } catch (CloneNotSupportedException e) {
532 throw new RuntimeException(e.getMessage());
533 }
534 }
535 }
536