hunt.shiro.authc.pam.FirstSuccessfulStrategy source code

1 /*
2  * Licensed to the Apache Software Foundation (ASF) under one
3  * or more contributor license agreements.  See the NOTICE file
4  * distributed with this work for additional information
5  * regarding copyright ownership.  The ASF licenses this file
6  * to you under the Apache License, Version 2.0 (the
7  * "License"); you may not use this file except in compliance
8  * with the License.  You may obtain a copy of the License at
9  *
10  *     http://www.apache.org/licenses/LICENSE-2.0
11  *
12  * Unless required by applicable law or agreed to in writing,
13  * software distributed under the License is distributed on an
14  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15  * KIND, either express or implied.  See the License for the
16  * specific language governing permissions and limitations
17  * under the License.
18  */
19 module hunt.shiro.authc.pam.FirstSuccessfulStrategy;
20 
21 import hunt.shiro.authc.pam.AbstractAuthenticationStrategy;
22 
23 import hunt.shiro.Exceptions;
24 import hunt.shiro.authc.AuthenticationInfo;
25 import hunt.shiro.authc.AuthenticationToken;
26 import hunt.shiro.realm.Realm;
27 import hunt.shiro.subject.PrincipalCollection;
28 
29 import hunt.collection;
30 
31 /**
32  * {@link AuthenticationStrategy} implementation that only accepts the account data from
33  * the first successfully consulted Realm and ignores all subsequent realms.  This is slightly
34  * different behavior than {@link AtLeastOneSuccessfulStrategy}, so please review both to see
35  * which one meets your needs better.
36  *
37  * @see AtLeastOneSuccessfulStrategy AtLeastOneSuccessfulAuthenticationStrategy
38  */
39 class FirstSuccessfulStrategy : AbstractAuthenticationStrategy {
40 
41     /**
42      * Returns {@code null} immediately, relying on this class's {@link #merge merge} implementation to return
43      * only the first {@code info} object it encounters, ignoring all subsequent ones.
44      */
45     override AuthenticationInfo beforeAllAttempts(Realm[] realms, AuthenticationToken token){
46         return null;
47     }
48 
49     private static bool isEmpty(PrincipalCollection pc) {
50         return pc  is null || pc.isEmpty();
51     }
52 
53     /**
54      * Returns the specified {@code aggregate} instance if is non null and valid (that is, has principals and they are
55      * not empty) immediately, or, if it is null or not valid, the {@code info} argument is returned instead.
56      * <p/>
57      * This logic ensures that the first valid info encountered is the one retained and all subsequent ones are ignored,
58      * since this strategy mandates that only the info from the first successfully authenticated realm be used.
59      */
60     override protected AuthenticationInfo merge(AuthenticationInfo info, AuthenticationInfo aggregate) {
61         if (aggregate !is null && isEmpty(aggregate.getPrincipals())) {
62             return aggregate;
63         }
64         return info !is null ? info : aggregate;
65     }
66 }