001 /**
002 *
003 * Copyright 2003-2004 The Apache Software Foundation
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018 //
019 // This source code implements specifications defined by the Java
020 // Community Process. In order to remain compliant with the specification
021 // DO NOT add / change / or delete method signatures!
022 //
023
024 package javax.servlet.http;
025
026 import java.text.MessageFormat;
027 import java.util.ResourceBundle;
028
029 /**
030 * Creates a cookie, a small amount of information sent by a servlet to
031 * a Web browser, saved by the browser, and later sent back to the server.
032 * A cookie's value can uniquely
033 * identify a client, so cookies are commonly used for session management.
034 *
035 * <p>A cookie has a name, a single value, and optional attributes
036 * such as a comment, path and domain qualifiers, a maximum age, and a
037 * version number. Some Web browsers have bugs in how they handle the
038 * optional attributes, so use them sparingly to improve the interoperability
039 * of your servlets.
040 *
041 * <p>The servlet sends cookies to the browser by using the
042 * {@link HttpServletResponse#addCookie} method, which adds
043 * fields to HTTP response headers to send cookies to the
044 * browser, one at a time. The browser is expected to
045 * support 20 cookies for each Web server, 300 cookies total, and
046 * may limit cookie size to 4 KB each.
047 *
048 * <p>The browser returns cookies to the servlet by adding
049 * fields to HTTP request headers. Cookies can be retrieved
050 * from a request by using the {@link HttpServletRequest#getCookies} method.
051 * Several cookies might have the same name but different path attributes.
052 *
053 * <p>Cookies affect the caching of the Web pages that use them.
054 * HTTP 1.0 does not cache pages that use cookies created with
055 * this class. This class does not support the cache control
056 * defined with HTTP 1.1.
057 *
058 * <p>This class supports both the Version 0 (by Netscape) and Version 1
059 * (by RFC 2109) cookie specifications. By default, cookies are
060 * created using Version 0 to ensure the best interoperability.
061 *
062 * @version $Rev: 46019 $ $Date: 2004-09-14 02:56:06 -0700 (Tue, 14 Sep 2004) $
063 */
064
065 // XXX would implement java.io.Serializable too, but can't do that
066 // so long as sun.servlet.* must run on older JDK 1.02 JVMs which
067 // don't include that support.
068
069 public class Cookie implements Cloneable {
070 private static final String LSTRING_FILE = "javax.servlet.http.LocalStrings";
071 private static ResourceBundle lStrings = ResourceBundle.getBundle(LSTRING_FILE);
072
073 //
074 // The value of the cookie itself.
075 //
076
077 private String name; // NAME= ... "$Name" style is reserved
078 private String value; // value of NAME
079
080 //
081 // Attributes encoded in the header's cookie fields.
082 //
083
084 private String comment; // ;Comment=VALUE ... describes cookie's use
085 // ;Discard ... implied by maxAge < 0
086 private String domain; // ;Domain=VALUE ... domain that sees cookie
087 private int maxAge = -1; // ;Max-Age=VALUE ... cookies auto-expire
088 private String path; // ;Path=VALUE ... URLs that see the cookie
089 private boolean secure; // ;Secure ... e.g. use SSL
090 private int version = 0; // ;Version=1 ... means RFC 2109++ style
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) or it is one of the tokens reserved for use
117 * by the cookie protocol
118 *
119 * @see #setValue
120 * @see #setVersion
121 */
122 public Cookie(String name, String value) {
123 if (!isToken(name)
124 || name.equalsIgnoreCase("Comment") // rfc2019
125 || name.equalsIgnoreCase("Discard") // 2019++
126 || name.equalsIgnoreCase("Domain")
127 || name.equalsIgnoreCase("Expires") // (old cookies)
128 || name.equalsIgnoreCase("Max-Age") // rfc2019
129 || name.equalsIgnoreCase("Path")
130 || name.equalsIgnoreCase("Secure")
131 || name.equalsIgnoreCase("Version")
132 || name.startsWith("$")
133 ) {
134 String errMsg = lStrings.getString("err.cookie_name_is_token");
135 Object[] errArgs = new Object[1];
136 errArgs[0] = name;
137 errMsg = MessageFormat.format(errMsg, errArgs);
138 throw new IllegalArgumentException(errMsg);
139 }
140
141 this.name = name;
142 this.value = value;
143 }
144
145 /**
146 * Specifies a comment that describes a cookie's purpose.
147 * The comment is useful if the browser presents the cookie
148 * to the user. Comments
149 * are not supported by Netscape Version 0 cookies.
150 *
151 * @param purpose a <code>String</code> specifying the comment
152 * to display to the user
153 *
154 * @see #getComment
155 */
156 public void setComment(String purpose) {
157 comment = purpose;
158 }
159
160 /**
161 * Returns the comment describing the purpose of this cookie, or
162 * <code>null</code> if the cookie has no comment.
163 *
164 * @return a <code>String</code> containing the comment,
165 * or <code>null</code> if none
166 *
167 * @see #setComment
168 */
169 public String getComment() {
170 return comment;
171 }
172
173 /**
174 * Specifies the domain within which this cookie should be presented.
175 *
176 * <p>The form of the domain name is specified by RFC 2109. A domain
177 * name begins with a dot (<code>.foo.com</code>) and means that
178 * the cookie is visible to servers in a specified Domain Name System
179 * (DNS) zone (for example, <code>www.foo.com</code>, but not
180 * <code>a.b.foo.com</code>). By default, cookies are only returned
181 * to the server that sent them.
182 *
183 * @param pattern a <code>String</code> containing the domain name
184 * within which this cookie is visible; form is according to RFC 2109
185 *
186 * @see #getDomain
187 */
188 public void setDomain(String pattern) {
189 domain = pattern.toLowerCase(); // IE allegedly needs this
190 }
191
192 /**
193 * Returns the domain name set for this cookie. The form of
194 * the domain name is set by RFC 2109.
195 *
196 * @return a <code>String</code> containing the domain name
197 *
198 * @see #setDomain
199 */
200 public String getDomain() {
201 return domain;
202 }
203
204 /**
205 * Sets the maximum age of the cookie in seconds.
206 *
207 * <p>A positive value indicates that the cookie will expire
208 * after that many seconds have passed. Note that the value is
209 * the <i>maximum</i> age when the cookie will expire, not the cookie's
210 * current age.
211 *
212 * <p>A negative value means
213 * that the cookie is not stored persistently and will be deleted
214 * when the Web browser exits. A zero value causes the cookie
215 * to be deleted.
216 *
217 * @param expiry an integer specifying the maximum age of the
218 * cookie in seconds; if negative, means the cookie is not stored;
219 * if zero, deletes the cookie
220 *
221 * @see #getMaxAge
222 */
223 public void setMaxAge(int expiry) {
224 maxAge = expiry;
225 }
226
227 /**
228 * Returns the maximum age of the cookie, specified in seconds,
229 * By default, <code>-1</code> indicating the cookie will persist
230 * until browser shutdown.
231 *
232 * @return an integer specifying the maximum age of the
233 * cookie in seconds; if negative, means the cookie persists
234 * until browser shutdown
235 *
236 * @see #setMaxAge
237 */
238 public int getMaxAge() {
239 return maxAge;
240 }
241
242 /**
243 * Specifies a path for the cookie
244 * to which the client should return the cookie.
245 *
246 * <p>The cookie is visible to all the pages in the directory
247 * you specify, and all the pages in that directory's subdirectories.
248 * A cookie's path must include the servlet that set the cookie,
249 * for example, <i>/catalog</i>, which makes the cookie
250 * visible to all directories on the server under <i>/catalog</i>.
251 *
252 * <p>Consult RFC 2109 (available on the Internet) for more
253 * information on setting path names for cookies.
254 *
255 * @param uri a <code>String</code> specifying a path
256 *
257 * @see #getPath
258 */
259 public void setPath(String uri) {
260 path = uri;
261 }
262
263 /**
264 * Returns the path on the server
265 * to which the browser returns this cookie. The
266 * cookie is visible to all subpaths on the server.
267 *
268 * @return a <code>String</code> specifying a path that contains
269 * a servlet name, for example, <i>/catalog</i>
270 *
271 * @see #setPath
272 */
273 public String getPath() {
274 return path;
275 }
276
277 /**
278 * Indicates to the browser whether the cookie should only be sent
279 * using a secure protocol, such as HTTPS or SSL.
280 *
281 * <p>The default value is <code>false</code>.
282 *
283 * @param flag if <code>true</code>, sends the cookie from the browser
284 * to the server only when using a secure protocol; if <code>false</code>,
285 * sent on any protocol
286 *
287 * @see #getSecure
288 */
289 public void setSecure(boolean flag) {
290 secure = flag;
291 }
292
293 /**
294 * Returns <code>true</code> if the browser is sending cookies
295 * only over a secure protocol, or <code>false</code> if the
296 * browser can send cookies using any protocol.
297 *
298 * @return <code>true</code> if the browser uses a secure protocol;
299 * otherwise, <code>true</code>
300 *
301 * @see #setSecure
302 */
303 public boolean getSecure() {
304 return secure;
305 }
306
307 /**
308 * Returns the name of the cookie. The name cannot be changed after
309 * creation.
310 *
311 * @return a <code>String</code> specifying the cookie's name
312 */
313 public String getName() {
314 return name;
315 }
316
317 /**
318 * Assigns a new value to a cookie after the cookie is created.
319 * If you use a binary value, you may want to use BASE64 encoding.
320 *
321 * <p>With Version 0 cookies, values should not contain white
322 * space, brackets, parentheses, equals signs, commas,
323 * double quotes, slashes, question marks, at signs, colons,
324 * and semicolons. Empty values may not behave the same way
325 * on all browsers.
326 *
327 * @param newValue a <code>String</code> specifying the new value
328 *
329 * @see #getValue
330 * @see Cookie
331 */
332 public void setValue(String newValue) {
333 value = newValue;
334 }
335
336 /**
337 * Returns the value of the cookie.
338 *
339 * @return a <code>String</code> containing the cookie's
340 * present value
341 *
342 * @see #setValue
343 * @see Cookie
344 */
345 public String getValue() {
346 return value;
347 }
348
349 /**
350 * Returns the version of the protocol this cookie complies
351 * with. Version 1 complies with RFC 2109,
352 * and version 0 complies with the original
353 * cookie specification drafted by Netscape. Cookies provided
354 * by a browser use and identify the browser's cookie version.
355 *
356 * @return 0 if the cookie complies with the original Netscape
357 * specification; 1 if the cookie complies with RFC 2109
358 *
359 * @see #setVersion
360 */
361 public int getVersion() {
362 return version;
363 }
364
365 /**
366 * Sets the version of the cookie protocol this cookie complies
367 * with. Version 0 complies with the original Netscape cookie
368 * specification. Version 1 complies with RFC 2109.
369 *
370 * <p>Since RFC 2109 is still somewhat new, consider
371 * version 1 as experimental; do not use it yet on production sites.
372 *
373 * @param v 0 if the cookie should comply with the original Netscape
374 * specification; 1 if the cookie should comply with RFC 2109
375 *
376 * @see #getVersion
377 */
378 public void setVersion(int v) {
379 version = v;
380 }
381
382 // Note -- disabled for now to allow full Netscape compatibility
383 // from RFC 2068, token special case characters
384 //
385 // private static final String tspecials = "()<>@,;:\\\"/[]?={} \t";
386
387 private static final String tspecials = ",; ";
388
389 /**
390 * Tests a string and returns true if the string counts as a
391 * reserved token in the Java language.
392 *
393 * @param value the <code>String</code> to be tested
394 *
395 * @return <code>true</code> if the <code>String</code> is
396 * a reserved token; <code>false</code> if it is not
397 */
398 private boolean isToken(String value) {
399 int len = value.length();
400
401 for (int i = 0; i < len; i++) {
402 char c = value.charAt(i);
403
404 if (c < 0x20 || c >= 0x7f || tspecials.indexOf(c) != -1)
405 return false;
406 }
407 return true;
408 }
409
410 /**
411 * Overrides the standard <code>java.lang.Object.clone</code>
412 * method to return a copy of this cookie.
413 */
414 public Object clone() {
415 try {
416 return super.clone();
417 } catch (CloneNotSupportedException e) {
418 throw new RuntimeException(e.getMessage());
419 }
420 }
421 }
422