001/*
002 * ====================================================================
003 * Licensed to the Apache Software Foundation (ASF) under one
004 * or more contributor license agreements.  See the NOTICE file
005 * distributed with this work for additional information
006 * regarding copyright ownership.  The ASF licenses this file
007 * to you under the Apache License, Version 2.0 (the
008 * "License"); you may not use this file except in compliance
009 * with the License.  You may obtain a copy of the License at
010 *
011 *   http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing,
014 * software distributed under the License is distributed on an
015 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
016 * KIND, either express or implied.  See the License for the
017 * specific language governing permissions and limitations
018 * under the License.
019 * ====================================================================
020 *
021 * This software consists of voluntary contributions made by many
022 * individuals on behalf of the Apache Software Foundation.  For more
023 * information on the Apache Software Foundation, please see
024 * <http://www.apache.org/>.
025 *
026 */
027package org.apache.http.auth;
028
029import org.apache.http.Header;
030import org.apache.http.HttpRequest;
031
032/**
033 * This interface represents an abstract challenge-response oriented
034 * authentication scheme.
035 * <p>
036 * An authentication scheme should be able to support the following
037 * functions:
038 * <ul>
039 *   <li>Parse and process the challenge sent by the target server
040 *       in response to request for a protected resource
041 *   <li>Provide its textual designation
042 *   <li>Provide its parameters, if available
043 *   <li>Provide the realm this authentication scheme is applicable to,
044 *       if available
045 *   <li>Generate authorization string for the given set of credentials
046 *       and the HTTP request in response to the authorization challenge.
047 * </ul>
048 * <p>
049 * Authentication schemes may be stateful involving a series of
050 * challenge-response exchanges.
051 * <p>
052 * IMPORTANT: implementations of this interface MUST also implement {@link ContextAwareAuthScheme}
053 * interface in order to remain API compatible with newer versions of HttpClient.
054 *
055 * @since 4.0
056 */
057
058public interface AuthScheme {
059
060    /**
061     * Processes the given challenge token. Some authentication schemes
062     * may involve multiple challenge-response exchanges. Such schemes must be able
063     * to maintain the state information when dealing with sequential challenges
064     *
065     * @param header the challenge header
066     */
067    void processChallenge(final Header header) throws MalformedChallengeException;
068
069    /**
070     * Returns textual designation of the given authentication scheme.
071     *
072     * @return the name of the given authentication scheme
073     */
074    String getSchemeName();
075
076    /**
077     * Returns authentication parameter with the given name, if available.
078     *
079     * @param name The name of the parameter to be returned
080     *
081     * @return the parameter with the given name
082     */
083    String getParameter(final String name);
084
085    /**
086     * Returns authentication realm. If the concept of an authentication
087     * realm is not applicable to the given authentication scheme, returns
088     * {@code null}.
089     *
090     * @return the authentication realm
091     */
092    String getRealm();
093
094    /**
095     * Tests if the authentication scheme is provides authorization on a per
096     * connection basis instead of usual per request basis
097     *
098     * @return {@code true} if the scheme is connection based, {@code false}
099     * if the scheme is request based.
100     */
101    boolean isConnectionBased();
102
103    /**
104     * Authentication process may involve a series of challenge-response exchanges.
105     * This method tests if the authorization process has been completed, either
106     * successfully or unsuccessfully, that is, all the required authorization
107     * challenges have been processed in their entirety.
108     *
109     * @return {@code true} if the authentication process has been completed,
110     * {@code false} otherwise.
111     */
112    boolean isComplete();
113
114    /**
115     * Produces an authorization string for the given set of {@link Credentials}.
116     *
117     * @param credentials The set of credentials to be used for athentication
118     * @param request The request being authenticated
119     * @throws AuthenticationException if authorization string cannot
120     *   be generated due to an authentication failure
121     *
122     * @return the authorization string
123     *
124     * @deprecated (4.1)  Use {@link ContextAwareAuthScheme#authenticate(Credentials, HttpRequest, org.apache.http.protocol.HttpContext)}
125     */
126    @Deprecated
127    Header authenticate(Credentials credentials, HttpRequest request)
128            throws AuthenticationException;
129
130}