Cookie.java

/*
 * Copyright (c) 1997, 2023 Oracle and/or its affiliates and others.
 * All rights reserved.
 * Copyright 2004 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package jakarta.servlet.http;

import java.io.Serializable;
import java.text.MessageFormat;
import java.util.Collections;
import java.util.Locale;
import java.util.Map;
import java.util.Objects;
import java.util.ResourceBundle;
import java.util.TreeMap;

/**
 *
 * Creates a cookie, a small amount of information sent by a servlet to a Web browser, saved by the browser, and later
 * sent back to the server. A cookie's value can uniquely identify a client, so cookies are commonly used for session
 * management.
 * 
 * <p>
 * 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.
 *
 * <p>
 * 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.
 * 
 * <p>
 * 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.
 * 
 * <p>
 * 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.
 *
 * <p>
 * This class supports cookies as defined by <a href="http://www.ietf.org/rfc/rfc6265.txt">RFC 6265</a>.
 *
 * @author Various
 */
public class Cookie implements Cloneable, Serializable {

    private static final long serialVersionUID = -5433071011125749022L;

    private static final String TSPECIALS;

    private static final String LSTRING_FILE = "jakarta.servlet.http.LocalStrings";

    private static final String DOMAIN = "Domain"; // ;Domain=VALUE ... domain that sees cookie
    private static final String MAX_AGE = "Max-Age"; // ;Max-Age=VALUE ... cookies auto-expire
    private static final String PATH = "Path"; // ;Path=VALUE ... URLs that see the cookie
    private static final String SECURE = "Secure"; // ;Secure ... e.g. use SSL
    private static final String HTTP_ONLY = "HttpOnly";

    private static final ResourceBundle lStrings = ResourceBundle.getBundle(LSTRING_FILE);

    static {
        boolean enforced = Boolean.valueOf(System.getProperty("org.glassfish.web.rfc2109_cookie_names_enforced", "true"));

        if (enforced) {
            TSPECIALS = "/()<>@,;:\\\"[]?={} \t";
        } else {
            TSPECIALS = ",; ";
        }
    }

    //
    // The value of the cookie itself.
    //
    private final String name; // NAME= ... "$Name" style is reserved
    private String value; // value of NAME

    //
    // Attributes encoded in the header's cookie fields.
    //
    private Map<String, String> attributes = null;

    /**
     * Constructs a cookie with the specified name and value.
     *
     * <p>
     * The name must conform to RFC 6265. However, vendors may provide a configuration option that allows cookie names
     * conforming to the original Netscape Cookie Specification to be accepted.
     *
     * <p>
     * The name of a cookie cannot be changed once the cookie has been created.
     *
     * <p>
     * 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 <code>setValue</code> 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.isEmpty()) {
            throw new IllegalArgumentException(createErrorMessage("err.cookie_name_blank"));
        }

        if (hasReservedCharacters(name)) {
            throw new IllegalArgumentException(createErrorMessage("err.cookie_name_invalid", name));
        }

        this.name = name;
        this.value = value;
    }

    /**
     * With the adoption of support for RFC 6265, this method should no longer be used.
     * <p>
     * If called, this method has no effect.
     *
     * @param purpose This parameter is ignored
     *
     * @see #getComment
     * 
     * @deprecated This is no longer required with RFC 6265
     */
    @Deprecated(since = "Servlet 6.0", forRemoval = true)
    public void setComment(String purpose) {
        // NO-OP
    }

    /**
     * With the adoption of support for RFC 6265, this method should no longer be used.
     *
     * @return Always {@code null}
     *
     * @see #setComment
     * 
     * @deprecated This is no longer required with RFC 6265
     */
    @Deprecated(since = "Servlet 6.0", forRemoval = true)
    public String getComment() {
        return null;
    }

    /**
     *
     * Specifies the domain within which this cookie should be presented.
     *
     * <p>
     * The form of the domain name is specified by RFC 6265. A domain name begins with a dot (<code>.foo.com</code>) and
     * means that the cookie is visible to servers in a specified Domain Name System (DNS) zone (for example,
     * <code>www.foo.com</code>, but not <code>a.b.foo.com</code>). 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 6265
     *
     * @see #getDomain
     */
    public void setDomain(String domain) {
        putAttribute(DOMAIN, domain != null ? domain.toLowerCase(Locale.ENGLISH) : null); // IE allegedly needs this
    }

    /**
     * Gets the domain name of this Cookie.
     *
     * <p>
     * Domain names are formatted according to RFC 6265.
     *
     * @return the domain name of this Cookie
     *
     * @see #setDomain
     */
    public String getDomain() {
        return getAttribute(DOMAIN);
    }

    /**
     * Sets the maximum age in seconds for this Cookie.
     *
     * <p>
     * A positive value indicates that the cookie will expire after that many seconds have passed. Note that the value is
     * the <i>maximum</i> age when the cookie will expire, not the cookie's current age.
     *
     * <p>
     * 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) {
        putAttribute(MAX_AGE, expiry < 0 ? null : String.valueOf(expiry));
    }

    /**
     * Gets the maximum age in seconds of this Cookie.
     *
     * <p>
     * By default, <code>-1</code> 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() {
        String maxAge = getAttribute(MAX_AGE);
        return maxAge == null ? -1 : Integer.parseInt(maxAge);
    }

    /**
     * Specifies a path for the cookie to which the client should return the cookie.
     *
     * <p>
     * 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, <i>/catalog</i>, which
     * makes the cookie visible to all directories on the server under <i>/catalog</i>.
     *
     * <p>
     * Consult <a href="http://www.ietf.org/rfc/rfc6265.txt">RFC 6265</a> for more information on setting path names for
     * cookies.
     *
     *
     * @param uri a <code>String</code> specifying a path
     *
     * @see #getPath
     */
    public void setPath(String uri) {
        putAttribute(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 <code>String</code> specifying a path that contains a servlet name, for example, <i>/catalog</i>
     *
     * @see #setPath
     */
    public String getPath() {
        return getAttribute(PATH);
    }

    /**
     * Indicates to the browser whether the cookie should only be sent using a secure protocol, such as HTTPS or SSL.
     *
     * <p>
     * The default value is <code>false</code>.
     *
     * @param flag if <code>true</code>, sends the cookie from the browser to the server only when using a secure protocol;
     * if <code>false</code>, sent on any protocol
     *
     * @see #getSecure
     */
    public void setSecure(boolean flag) {
        putAttribute(SECURE, String.valueOf(flag));
    }

    /**
     * Returns <code>true</code> if the browser is sending cookies only over a secure protocol, or <code>false</code> if the
     * browser can send cookies using any protocol.
     *
     * @return <code>true</code> if the browser uses a secure protocol, <code>false</code> otherwise
     *
     * @see #setSecure
     */
    public boolean getSecure() {
        return Boolean.parseBoolean(getAttribute(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.
     * 
     * <p>
     * If you use a binary value, you may want to use BASE64 encoding.
     *
     * <p>
     * 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;
    }

    /**
     * With the adoption of support for RFC 6265, this method should no longer be used.
     * 
     * @return Always 0
     *
     * @see #setVersion
     * 
     * @deprecated This is no longer required with RFC 6265
     */
    @Deprecated(since = "Servlet 6.0", forRemoval = true)
    public int getVersion() {
        return 0;
    }

    /**
     * With the adoption of support for RFC 6265, this method should no longer be used.
     * <p>
     * If called, this method has no effect.
     *
     * @param v This parameter is ignored
     *
     * @see #getVersion
     * 
     * @deprecated This is no longer required with RFC 6265
     */
    @Deprecated(since = "Servlet 6.0", forRemoval = true)
    public void setVersion(int v) {
        // NO-OP
    }

    /*
     * Tests a string and returns true if the string contains a reserved characters for the Set-Cookie header.
     * 
     * @param value the <code>String</code> to be tested
     *
     * @return <code>true</code> if the <code>String</code> contains a reserved character for the Set-Cookie header;
     * <code>false</code> otherwise
     */
    private static boolean hasReservedCharacters(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 true;
            }
        }

        return false;
    }

    /*
     * Create error message to be set as exception detail message.
     */
    private static String createErrorMessage(String key, Object... arguments) {
        String errMsg = lStrings.getString(key);
        return MessageFormat.format(errMsg, arguments);
    }

    /**
     * Overrides the standard <code>java.lang.Object.clone</code> method to return a copy of this Cookie.
     */
    @Override
    public Object clone() {
        try {
            Cookie clone = (Cookie) super.clone();
            if (attributes != null) {
                clone.attributes = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
                clone.attributes.putAll(attributes);
            }
            return clone;
        } catch (CloneNotSupportedException e) {
            throw new RuntimeException(e.getMessage());
        }
    }

    /**
     * Marks or unmarks this Cookie as <i>HttpOnly</i>.
     *
     * <p>
     * If <tt>httpOnly</tt> is set to <tt>true</tt>, this cookie is marked as <i>HttpOnly</i>, by adding the
     * <tt>HttpOnly</tt> attribute to it.
     *
     * <p>
     * <i>HttpOnly</i> 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 httpOnly true if this cookie is to be marked as <i>HttpOnly</i>, false otherwise
     *
     * @since Servlet 3.0
     */
    public void setHttpOnly(boolean httpOnly) {
        putAttribute(HTTP_ONLY, String.valueOf(httpOnly));
    }

    /**
     * Checks whether this Cookie has been marked as <i>HttpOnly</i>.
     *
     * @return true if this Cookie has been marked as <i>HttpOnly</i>, false otherwise
     *
     * @since Servlet 3.0
     */
    public boolean isHttpOnly() {
        return Boolean.parseBoolean(getAttribute(HTTP_ONLY));
    }

    /**
     * Sets the value of the cookie attribute associated with the given name.
     * 
     * <p>
     * This should sync to any predefined attribute for which already a getter/setter pair exist in the current version,
     * except for <code>version</code>. E.g. when <code>cookie.setAttribute("domain", domain)</code> is invoked, then
     * <code>cookie.getDomain()</code> should return exactly that value, and vice versa.
     * 
     * @param name the name of the cookie attribute to set the value for, case insensitive
     * 
     * @param value the value of the cookie attribute associated with the given name, can be {@code null}
     *
     * @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.
     *
     * @throws NumberFormatException if the cookie is a known field with a numerical value (eg Max-Age), but the value is
     * not able to be parsed.
     *
     * @since Servlet 6.0
     */
    public void setAttribute(String name, String value) {
        if (name == null || name.isEmpty()) {
            throw new IllegalArgumentException(createErrorMessage("err.cookie_attribute_name_blank"));
        }

        if (hasReservedCharacters(name)) {
            throw new IllegalArgumentException(createErrorMessage("err.cookie_attribute_name_invalid", name));
        }

        if (MAX_AGE.equalsIgnoreCase(name) && value != null) {
            setMaxAge(Integer.parseInt(value));
        } else {
            putAttribute(name, value);
        }
    }

    private void putAttribute(String name, String value) {
        if (attributes == null) {
            attributes = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
        }

        if (value == null) {
            attributes.remove(name);
        } else {
            attributes.put(name, value);
        }
    }

    /**
     * Gets the value of the cookie attribute associated with the given name.
     *
     * <p>
     * This should sync to any predefined attribute for which already a getter/setter pair exist in the current version,
     * except for <code>version</code>. E.g. when <code>cookie.setAttribute("domain", domain)</code> is invoked, then
     * <code>cookie.getDomain()</code> should return exactly that value, and vice versa.
     *
     * @param name the name of the cookie attribute to get the value of, case insensitive
     *
     * @return the value of the cookie attribute associated with the given name
     * 
     * @since Servlet 6.0
     */
    public String getAttribute(String name) {
        return attributes == null ? null : attributes.get(name);
    }

    /**
     * Returns an unmodifiable mapping of all cookie attributes set via {@link #setAttribute(String, String)} as well as any
     * predefined setter method, except for <code>version</code>.
     * 
     * @return an unmodifiable mapping of all cookie attributes set via <code>setAttribute(String, String)</code> as well as
     * any predefined setter method, except for <code>version</code>
     * 
     * @since Servlet 6.0
     */
    public Map<String, String> getAttributes() {
        return attributes == null ? Collections.emptyMap() : Collections.unmodifiableMap(attributes);
    }

    @Override
    public int hashCode() {
        return Objects.hash(name, value, attributes);
    }

    @Override
    public boolean equals(Object obj) {
        if (obj instanceof Cookie) {
            Cookie c = (Cookie) obj;
            return Objects.equals(getName(), c.getName()) &&
                    Objects.equals(getValue(), c.getValue()) &&
                    getVersion() == c.getVersion() &&
                    Objects.equals(getAttributes(), c.getAttributes());
        }
        return false;
    }

    @Override
    public String toString() {
        return String.format("%s{%s=%s,%s}", super.toString(), name, value, attributes);
    }
}