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 public class Cookie implements Cloneable {
065
066 private static final String LSTRING_FILE = "javax.servlet.http.LocalStrings";
067 private static ResourceBundle lStrings = ResourceBundle
068 .getBundle(LSTRING_FILE);
069
070 //
071 // The value of the cookie itself.
072 //
073
074 private String name; // NAME= ... "$Name" style is reserved
075 private String value; // value of NAME
076
077 //
078 // Attributes encoded in the header's cookie fields.
079 //
080
081 private String comment; // ;Comment=VALUE ... describes cookie's use
082 // ;Discard ... implied by maxAge < 0
083 private String domain; // ;Domain=VALUE ... domain that sees cookie
084 private int maxAge = -1; // ;Max-Age=VALUE ... cookies auto-expire
085 private String path; // ;Path=VALUE ... URLs that see the cookie
086 private boolean secure; // ;Secure ... e.g. use SSL
087 private int version = 0; // ;Version=1 ... means RFC 2109++ style
088
089 /**
090 * Constructs a cookie with a specified name and value.
091 *
092 * <p>The name must conform to RFC 2109. That means it can contain
093 * only ASCII alphanumeric characters and cannot contain commas,
094 * semicolons, or white space or begin with a $ character. The cookie's
095 * name cannot be changed after creation.
096 *
097 * <p>The value can be anything the server chooses to send. Its
098 * value is probably of interest only to the server. The cookie's
099 * value can be changed after creation with the
100 * <code>setValue</code> method.
101 *
102 * <p>By default, cookies are created according to the Netscape
103 * cookie specification. The version can be changed with the
104 * <code>setVersion</code> method.
105 *
106 *
107 * @param name a <code>String</code> specifying the name of the cookie
108 *
109 * @param value a <code>String</code> specifying the value of the cookie
110 *
111 * @throws IllegalArgumentException if the cookie name contains illegal characters
112 * (for example, a comma, space, or semicolon)
113 * or it is one of the tokens reserved for use
114 * by the cookie protocol
115 * @see #setValue
116 * @see #setVersion
117 *
118 */
119
120 public Cookie(String name, String value) {
121 if (!isToken(name)
122 || name.equalsIgnoreCase("Comment") // rfc2019
123 || name.equalsIgnoreCase("Discard") // 2019++
124 || name.equalsIgnoreCase("Domain")
125 || name.equalsIgnoreCase("Expires") // (old cookies)
126 || name.equalsIgnoreCase("Max-Age") // rfc2019
127 || name.equalsIgnoreCase("Path")
128 || name.equalsIgnoreCase("Secure")
129 || name.equalsIgnoreCase("Version")
130 || name.startsWith("$")) {
131 String errMsg = lStrings
132 .getString("err.cookie_name_is_token");
133 Object[] errArgs = new Object[1];
134 errArgs[0] = name;
135 errMsg = MessageFormat.format(errMsg, errArgs);
136 throw new IllegalArgumentException(errMsg);
137 }
138
139 this .name = name;
140 this .value = value;
141 }
142
143 /**
144 *
145 * Specifies a comment that describes a cookie's purpose.
146 * The comment is useful if the browser presents the cookie
147 * to the user. Comments
148 * are not supported by Netscape Version 0 cookies.
149 *
150 * @param purpose a <code>String</code> specifying the comment
151 * to display to the user
152 *
153 * @see #getComment
154 *
155 */
156
157 public void setComment(String purpose) {
158 comment = purpose;
159 }
160
161 /**
162 * Returns the comment describing the purpose of this cookie, or
163 * <code>null</code> if the cookie has no comment.
164 *
165 * @return a <code>String</code> containing the comment,
166 * or <code>null</code> if none
167 *
168 * @see #setComment
169 *
170 */
171
172 public String getComment() {
173 return comment;
174 }
175
176 /**
177 *
178 * Specifies the domain within which this cookie should be presented.
179 *
180 * <p>The form of the domain name is specified by RFC 2109. A domain
181 * name begins with a dot (<code>.foo.com</code>) and means that
182 * the cookie is visible to servers in a specified Domain Name System
183 * (DNS) zone (for example, <code>www.foo.com</code>, but not
184 * <code>a.b.foo.com</code>). By default, cookies are only returned
185 * to the server that sent them.
186 *
187 *
188 * @param pattern a <code>String</code> containing the domain name
189 * within which this cookie is visible;
190 * form is according to RFC 2109
191 *
192 * @see #getDomain
193 *
194 */
195
196 public void setDomain(String pattern) {
197 domain = pattern.toLowerCase(); // IE allegedly needs this
198 }
199
200 /**
201 * Returns the domain name set for this cookie. The form of
202 * the domain name is set by RFC 2109.
203 *
204 * @return a <code>String</code> containing the domain name
205 *
206 * @see #setDomain
207 *
208 */
209
210 public String getDomain() {
211 return domain;
212 }
213
214 /**
215 * Sets the maximum age of the cookie in seconds.
216 *
217 * <p>A positive value indicates that the cookie will expire
218 * after that many seconds have passed. Note that the value is
219 * the <i>maximum</i> age when the cookie will expire, not the cookie's
220 * current age.
221 *
222 * <p>A negative value means
223 * that the cookie is not stored persistently and will be deleted
224 * when the Web browser exits. A zero value causes the cookie
225 * to be deleted.
226 *
227 * @param expiry an integer specifying the maximum age of the
228 * cookie in seconds; if negative, means
229 * the cookie is not stored; if zero, deletes
230 * the cookie
231 *
232 *
233 * @see #getMaxAge
234 *
235 */
236
237 public void setMaxAge(int expiry) {
238 maxAge = expiry;
239 }
240
241 /**
242 * Returns the maximum age of the cookie, specified in seconds,
243 * By default, <code>-1</code> indicating the cookie will persist
244 * until browser shutdown.
245 *
246 *
247 * @return an integer specifying the maximum age of the
248 * cookie in seconds; if negative, means
249 * the cookie persists until browser shutdown
250 *
251 *
252 * @see #setMaxAge
253 *
254 */
255
256 public int getMaxAge() {
257 return maxAge;
258 }
259
260 /**
261 * Specifies a path for the cookie
262 * to which the client should return the cookie.
263 *
264 * <p>The cookie is visible to all the pages in the directory
265 * you specify, and all the pages in that directory's subdirectories.
266 * A cookie's path must include the servlet that set the cookie,
267 * for example, <i>/catalog</i>, which makes the cookie
268 * visible to all directories on the server under <i>/catalog</i>.
269 *
270 * <p>Consult RFC 2109 (available on the Internet) for more
271 * information on setting path names for cookies.
272 *
273 *
274 * @param uri a <code>String</code> specifying a path
275 *
276 *
277 * @see #getPath
278 *
279 */
280
281 public void setPath(String uri) {
282 path = uri;
283 }
284
285 /**
286 * Returns the path on the server
287 * to which the browser returns this cookie. The
288 * cookie is visible to all subpaths on the server.
289 *
290 *
291 * @return a <code>String</code> specifying a path that contains
292 * a servlet name, for example, <i>/catalog</i>
293 *
294 * @see #setPath
295 *
296 */
297
298 public String getPath() {
299 return path;
300 }
301
302 /**
303 * Indicates to the browser whether the cookie should only be sent
304 * using a secure protocol, such as HTTPS or SSL.
305 *
306 * <p>The default value is <code>false</code>.
307 *
308 * @param flag if <code>true</code>, sends the cookie from the browser
309 * to the server only when using a secure protocol;
310 * if <code>false</code>, sent on any protocol
311 *
312 * @see #getSecure
313 *
314 */
315
316 public void setSecure(boolean flag) {
317 secure = flag;
318 }
319
320 /**
321 * Returns <code>true</code> if the browser is sending cookies
322 * only over a secure protocol, or <code>false</code> if the
323 * browser can send cookies using any protocol.
324 *
325 * @return <code>true</code> if the browser uses a secure protocol;
326 * otherwise, <code>true</code>
327 *
328 * @see #setSecure
329 *
330 */
331
332 public boolean getSecure() {
333 return secure;
334 }
335
336 /**
337 * Returns the name of the cookie. The name cannot be changed after
338 * creation.
339 *
340 * @return a <code>String</code> specifying the cookie's name
341 *
342 */
343
344 public String getName() {
345 return name;
346 }
347
348 /**
349 *
350 * Assigns a new value to a cookie after the cookie is created.
351 * If you use a binary value, you may want to use BASE64 encoding.
352 *
353 * <p>With Version 0 cookies, values should not contain white
354 * space, brackets, parentheses, equals signs, commas,
355 * double quotes, slashes, question marks, at signs, colons,
356 * and semicolons. Empty values may not behave the same way
357 * on all browsers.
358 *
359 * @param newValue a <code>String</code> specifying the new value
360 *
361 *
362 * @see #getValue
363 * @see Cookie
364 *
365 */
366
367 public void setValue(String newValue) {
368 value = newValue;
369 }
370
371 /**
372 * Returns the value of the cookie.
373 *
374 * @return a <code>String</code> containing the cookie's
375 * present value
376 *
377 * @see #setValue
378 * @see Cookie
379 *
380 */
381
382 public String getValue() {
383 return value;
384 }
385
386 /**
387 * Returns the version of the protocol this cookie complies
388 * with. Version 1 complies with RFC 2109,
389 * and version 0 complies with the original
390 * cookie specification drafted by Netscape. Cookies provided
391 * by a browser use and identify the browser's cookie version.
392 *
393 *
394 * @return 0 if the cookie complies with the
395 * original Netscape specification; 1
396 * if the cookie complies with RFC 2109
397 *
398 * @see #setVersion
399 *
400 */
401
402 public int getVersion() {
403 return version;
404 }
405
406 /**
407 * Sets the version of the cookie protocol this cookie complies
408 * with. Version 0 complies with the original Netscape cookie
409 * specification. Version 1 complies with RFC 2109.
410 *
411 * <p>Since RFC 2109 is still somewhat new, consider
412 * version 1 as experimental; do not use it yet on production sites.
413 *
414 *
415 * @param v 0 if the cookie should comply with
416 * the original Netscape specification;
417 * 1 if the cookie should comply with RFC 2109
418 *
419 * @see #getVersion
420 *
421 */
422
423 public void setVersion(int v) {
424 version = v;
425 }
426
427 // Note -- disabled for now to allow full Netscape compatibility
428 // from RFC 2068, token special case characters
429 //
430 // private static final String tspecials = "()<>@,;:\\\"/[]?={} \t";
431
432 private static final String tspecials = ",; ";
433
434 /*
435 * Tests a string and returns true if the string counts as a
436 * reserved token in the Java language.
437 *
438 * @param value the <code>String</code> to be tested
439 *
440 * @return <code>true</code> if the <code>String</code> is
441 * a reserved token; <code>false</code>
442 * if it is not
443 */
444
445 private boolean isToken(String value) {
446 int len = value.length();
447
448 for (int i = 0; i < len; i++) {
449 char c = value.charAt(i);
450
451 if (c < 0x20 || c >= 0x7f || tspecials.indexOf(c) != -1)
452 return false;
453 }
454 return true;
455 }
456
457 /**
458 *
459 * Overrides the standard <code>java.lang.Object.clone</code>
460 * method to return a copy of this cookie.
461 *
462 *
463 */
464
465 public Object clone() {
466 try {
467 return super .clone();
468 } catch (CloneNotSupportedException e) {
469 throw new RuntimeException(e.getMessage());
470 }
471 }
472 }
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