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1   /*
2    * ====================================================================
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *   http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing,
14   * software distributed under the License is distributed on an
15   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16   * KIND, either express or implied.  See the License for the
17   * specific language governing permissions and limitations
18   * under the License.
19   * ====================================================================
20   *
21   * This software consists of voluntary contributions made by many
22   * individuals on behalf of the Apache Software Foundation.  For more
23   * information on the Apache Software Foundation, please see
24   * <http://www.apache.org/>.
25   *
26   */
27  
28  package org.apache.hc.client5.http.impl;
29  
30  import java.util.ArrayList;
31  import java.util.Arrays;
32  import java.util.Collection;
33  import java.util.Collections;
34  import java.util.List;
35  import java.util.Locale;
36  import java.util.Map;
37  
38  import org.apache.hc.client5.http.AuthenticationStrategy;
39  import org.apache.hc.client5.http.auth.AuthChallenge;
40  import org.apache.hc.client5.http.auth.AuthScheme;
41  import org.apache.hc.client5.http.auth.AuthSchemeFactory;
42  import org.apache.hc.client5.http.auth.StandardAuthScheme;
43  import org.apache.hc.client5.http.auth.ChallengeType;
44  import org.apache.hc.client5.http.config.RequestConfig;
45  import org.apache.hc.client5.http.protocol.HttpClientContext;
46  import org.apache.hc.core5.annotation.Contract;
47  import org.apache.hc.core5.annotation.ThreadingBehavior;
48  import org.apache.hc.core5.http.config.Lookup;
49  import org.apache.hc.core5.http.protocol.HttpContext;
50  import org.apache.hc.core5.util.Args;
51  import org.slf4j.Logger;
52  import org.slf4j.LoggerFactory;
53  
54  /**
55   * Default implementation of {@link AuthenticationStrategy}
56   *
57   * @since 5.0
58   */
59  @Contract(threading = ThreadingBehavior.STATELESS)
60  public class DefaultAuthenticationStrategy implements AuthenticationStrategy {
61  
62      private static final Logger LOG = LoggerFactory.getLogger(DefaultAuthenticationStrategy.class);
63  
64      public static final DefaultAuthenticationStrategycationStrategy.html#DefaultAuthenticationStrategy">DefaultAuthenticationStrategy INSTANCE = new DefaultAuthenticationStrategy();
65  
66      private static final List<String> DEFAULT_SCHEME_PRIORITY =
67          Collections.unmodifiableList(Arrays.asList(
68                  StandardAuthScheme.SPNEGO,
69                  StandardAuthScheme.KERBEROS,
70                  StandardAuthScheme.NTLM,
71                  StandardAuthScheme.DIGEST,
72                  StandardAuthScheme.BASIC));
73  
74      @Override
75      public List<AuthScheme> select(
76              final ChallengeType challengeType,
77              final Map<String, AuthChallenge> challenges,
78              final HttpContext context) {
79          Args.notNull(challengeType, "ChallengeType");
80          Args.notNull(challenges, "Map of auth challenges");
81          Args.notNull(context, "HTTP context");
82          final HttpClientContext clientContext = HttpClientContext.adapt(context);
83  
84          final List<AuthScheme> options = new ArrayList<>();
85          final Lookup<AuthSchemeFactory> registry = clientContext.getAuthSchemeRegistry();
86          if (registry == null) {
87              LOG.debug("Auth scheme registry not set in the context");
88              return options;
89          }
90          final RequestConfig config = clientContext.getRequestConfig();
91          Collection<String> authPrefs = challengeType == ChallengeType.TARGET ?
92                  config.getTargetPreferredAuthSchemes() : config.getProxyPreferredAuthSchemes();
93          if (authPrefs == null) {
94              authPrefs = DEFAULT_SCHEME_PRIORITY;
95          }
96          if (LOG.isDebugEnabled()) {
97              LOG.debug("Authentication schemes in the order of preference: {}", authPrefs);
98          }
99  
100         for (final String schemeName: authPrefs) {
101             final AuthChallenge challenge = challenges.get(schemeName.toLowerCase(Locale.ROOT));
102             if (challenge != null) {
103                 final AuthSchemeFactory authSchemeFactory = registry.lookup(schemeName);
104                 if (authSchemeFactory == null) {
105                     if (LOG.isWarnEnabled()) {
106                         LOG.warn("Authentication scheme {} not supported", schemeName);
107                         // Try again
108                     }
109                     continue;
110                 }
111                 final AuthScheme authScheme = authSchemeFactory.create(context);
112                 options.add(authScheme);
113             } else {
114                 if (LOG.isDebugEnabled()) {
115                     LOG.debug("Challenge for {} authentication scheme not available", schemeName);
116                 }
117             }
118         }
119         return options;
120     }
121 
122 }