A cookie has a name, a single value, and optional attributes * such as a comment, path and domain qualifiers, a maximum age, and a * version number. Some Web browsers have bugs in how they handle the * optional attributes, so use them sparingly to improve the interoperability * of your servlets. * *
The servlet sends cookies to the browser by using the * {@link HttpServletResponse#addCookie} method, which adds * fields to HTTP response headers to send cookies to the * browser, one at a time. The browser is expected to * support 20 cookies for each Web server, 300 cookies total, and * may limit cookie size to 4 KB each. * *
The browser returns cookies to the servlet by adding * fields to HTTP request headers. Cookies can be retrieved * from a request by using the {@link HttpServletRequest#getCookies} method. * Several cookies might have the same name but different path attributes. * *
Cookies affect the caching of the Web pages that use them. * HTTP 1.0 does not cache pages that use cookies created with * this class. This class does not support the cache control * defined with HTTP 1.1. * *
This class supports both the Version 0 (by Netscape) and Version 1 * (by RFC 2109) cookie specifications. By default, cookies are * created using Version 0 to ensure the best interoperability. * * @author Various */ public class Cookie implements Cloneable, Serializable { private static final long serialVersionUID = -6454587001725327448L; private static final String TSPECIALS; private static final String LSTRING_FILE = "javax.servlet.http.LocalStrings"; private static ResourceBundle lStrings = ResourceBundle.getBundle(LSTRING_FILE); static { if (Boolean.valueOf(System.getProperty("org.glassfish.web.rfc2109_cookie_names_enforced", "true"))) { TSPECIALS = "/()<>@,;:\\\"[]?={} \t"; } else { TSPECIALS = ",; "; } } // // The value of the cookie itself. // private String name; // NAME= ... "$Name" style is reserved private String value; // value of NAME // // Attributes encoded in the header's cookie fields. // private String comment; // ;Comment=VALUE ... describes cookie's use // ;Discard ... implied by maxAge < 0 private String domain; // ;Domain=VALUE ... domain that sees cookie private int maxAge = -1; // ;Max-Age=VALUE ... cookies auto-expire private String path; // ;Path=VALUE ... URLs that see the cookie private boolean secure; // ;Secure ... e.g. use SSL private int version = 0; // ;Version=1 ... means RFC 2109++ style private boolean isHttpOnly = false; /** * Constructs a cookie with the specified name and value. * *
The name must conform to RFC 2109. However, vendors may * provide a configuration option that allows cookie names conforming * to the original Netscape Cookie Specification to be accepted. * *
The name of a cookie cannot be changed once the cookie has * been created. * *
The value can be anything the server chooses to send. Its
* value is probably of interest only to the server. The cookie's
* value can be changed after creation with the
* setValue method.
*
*
By default, cookies are created according to the Netscape
* cookie specification. The version can be changed with the
* setVersion method.
*
* @param name the name of the cookie
*
* @param value the value of the cookie
*
* @throws IllegalArgumentException if the cookie name is null or
* empty or contains any illegal characters (for example, a comma,
* space, or semicolon) or matches a token reserved for use by the
* cookie protocol
*
* @see #setValue
* @see #setVersion
*/
public Cookie(String name, String value) {
if (name == null || name.length() == 0) {
throw new IllegalArgumentException(
lStrings.getString("err.cookie_name_blank"));
}
if (!isToken(name) ||
name.equalsIgnoreCase("Comment") || // rfc2019
name.equalsIgnoreCase("Discard") || // 2019++
name.equalsIgnoreCase("Domain") ||
name.equalsIgnoreCase("Expires") || // (old cookies)
name.equalsIgnoreCase("Max-Age") || // rfc2019
name.equalsIgnoreCase("Path") ||
name.equalsIgnoreCase("Secure") ||
name.equalsIgnoreCase("Version") ||
name.startsWith("$")) {
String errMsg = lStrings.getString("err.cookie_name_is_token");
Object[] errArgs = new Object[1];
errArgs[0] = name;
errMsg = MessageFormat.format(errMsg, errArgs);
throw new IllegalArgumentException(errMsg);
}
this.name = name;
this.value = value;
}
/**
* Specifies a comment that describes a cookie's purpose.
* The comment is useful if the browser presents the cookie
* to the user. Comments
* are not supported by Netscape Version 0 cookies.
*
* @param purpose a String specifying the comment
* to display to the user
*
* @see #getComment
*/
public void setComment(String purpose) {
comment = purpose;
}
/**
* Returns the comment describing the purpose of this cookie, or
* null if the cookie has no comment.
*
* @return the comment of the cookie, or null if unspecified
*
* @see #setComment
*/
public String getComment() {
return comment;
}
/**
*
* Specifies the domain within which this cookie should be presented.
*
*
The form of the domain name is specified by RFC 2109. A domain
* name begins with a dot (.foo.com) and means that
* the cookie is visible to servers in a specified Domain Name System
* (DNS) zone (for example, www.foo.com, but not
* a.b.foo.com). By default, cookies are only returned
* to the server that sent them.
*
* @param domain the domain name within which this cookie is visible;
* form is according to RFC 2109
*
* @see #getDomain
*/
public void setDomain(String domain) {
this.domain = domain.toLowerCase(Locale.ENGLISH); // IE allegedly needs this
}
/**
* Gets the domain name of this Cookie.
*
*
Domain names are formatted according to RFC 2109. * * @return the domain name of this Cookie * * @see #setDomain */ public String getDomain() { return domain; } /** * Sets the maximum age in seconds for this Cookie. * *
A positive value indicates that the cookie will expire * after that many seconds have passed. Note that the value is * the maximum age when the cookie will expire, not the cookie's * current age. * *
A negative value means * that the cookie is not stored persistently and will be deleted * when the Web browser exits. A zero value causes the cookie * to be deleted. * * @param expiry an integer specifying the maximum age of the * cookie in seconds; if negative, means * the cookie is not stored; if zero, deletes * the cookie * * @see #getMaxAge */ public void setMaxAge(int expiry) { maxAge = expiry; } /** * Gets the maximum age in seconds of this Cookie. * *
By default, -1 is returned, which indicates that
* the cookie will persist until browser shutdown.
*
* @return an integer specifying the maximum age of the
* cookie in seconds; if negative, means
* the cookie persists until browser shutdown
*
* @see #setMaxAge
*/
public int getMaxAge() {
return maxAge;
}
/**
* Specifies a path for the cookie
* to which the client should return the cookie.
*
*
The cookie is visible to all the pages in the directory * you specify, and all the pages in that directory's subdirectories. * A cookie's path must include the servlet that set the cookie, * for example, /catalog, which makes the cookie * visible to all directories on the server under /catalog. * *
Consult RFC 2109 (available on the Internet) for more
* information on setting path names for cookies.
*
*
* @param uri a String specifying a path
*
* @see #getPath
*/
public void setPath(String uri) {
path = uri;
}
/**
* Returns the path on the server
* to which the browser returns this cookie. The
* cookie is visible to all subpaths on the server.
*
* @return a String specifying a path that contains
* a servlet name, for example, /catalog
*
* @see #setPath
*/
public String getPath() {
return path;
}
/**
* Indicates to the browser whether the cookie should only be sent
* using a secure protocol, such as HTTPS or SSL.
*
*
The default value is false.
*
* @param flag if true, sends the cookie from the browser
* to the server only when using a secure protocol; if false,
* sent on any protocol
*
* @see #getSecure
*/
public void setSecure(boolean flag) {
secure = flag;
}
/**
* Returns true if the browser is sending cookies
* only over a secure protocol, or false if the
* browser can send cookies using any protocol.
*
* @return true if the browser uses a secure protocol,
* false otherwise
*
* @see #setSecure
*/
public boolean getSecure() {
return secure;
}
/**
* Returns the name of the cookie. The name cannot be changed after
* creation.
*
* @return the name of the cookie
*/
public String getName() {
return name;
}
/**
* Assigns a new value to this Cookie.
*
*
If you use a binary value, you may want to use BASE64 encoding. * *
With Version 0 cookies, values should not contain white * space, brackets, parentheses, equals signs, commas, * double quotes, slashes, question marks, at signs, colons, * and semicolons. Empty values may not behave the same way * on all browsers. * * @param newValue the new value of the cookie * * @see #getValue */ public void setValue(String newValue) { value = newValue; } /** * Gets the current value of this Cookie. * * @return the current value of this Cookie * * @see #setValue */ public String getValue() { return value; } /** * Returns the version of the protocol this cookie complies * with. Version 1 complies with RFC 2109, * and version 0 complies with the original * cookie specification drafted by Netscape. Cookies provided * by a browser use and identify the browser's cookie version. * * @return 0 if the cookie complies with the * original Netscape specification; 1 * if the cookie complies with RFC 2109 * * @see #setVersion */ public int getVersion() { return version; } /** * Sets the version of the cookie protocol that this Cookie complies * with. * *
Version 0 complies with the original Netscape cookie * specification. Version 1 complies with RFC 2109. * *
Since RFC 2109 is still somewhat new, consider
* version 1 as experimental; do not use it yet on production sites.
*
* @param v 0 if the cookie should comply with the original Netscape
* specification; 1 if the cookie should comply with RFC 2109
*
* @see #getVersion
*/
public void setVersion(int v) {
version = v;
}
/*
* Tests a string and returns true if the string counts as a
* reserved token in the Java language.
*
* @param value the String to be tested
*
* @return true if the String is a reserved
* token; false otherwise
*/
private boolean isToken(String value) {
int len = value.length();
for (int i = 0; i < len; i++) {
char c = value.charAt(i);
if (c < 0x20 || c >= 0x7f || TSPECIALS.indexOf(c) != -1) {
return false;
}
}
return true;
}
/**
* Overrides the standard java.lang.Object.clone
* method to return a copy of this Cookie.
*/
public Object clone() {
try {
return super.clone();
} catch (CloneNotSupportedException e) {
throw new RuntimeException(e.getMessage());
}
}
/**
* Marks or unmarks this Cookie as HttpOnly.
*
*
If isHttpOnly is set to true, this cookie is * marked as HttpOnly, by adding the HttpOnly attribute * to it. * *
HttpOnly cookies are not supposed to be exposed to * client-side scripting code, and may therefore help mitigate certain * kinds of cross-site scripting attacks. * * @param isHttpOnly true if this cookie is to be marked as * HttpOnly, false otherwise * * @since Servlet 3.0 */ public void setHttpOnly(boolean isHttpOnly) { this.isHttpOnly = isHttpOnly; } /** * Checks whether this Cookie has been marked as HttpOnly. * * @return true if this Cookie has been marked as HttpOnly, * false otherwise * * @since Servlet 3.0 */ public boolean isHttpOnly() { return isHttpOnly; } }