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1   package org.eclipse.aether.transport.http;
2   
3   /*
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   * 
12   *  http://www.apache.org/licenses/LICENSE-2.0
13   * 
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  
22  import org.apache.http.Header;
23  import org.apache.http.HttpHeaders;
24  import org.apache.http.HttpResponse;
25  
26  import javax.inject.Named;
27  import javax.inject.Singleton;
28  import java.util.Collections;
29  import java.util.Map;
30  
31  /**
32   * A component extracting Nexus2 ETag "shielded" style-checksums from response headers.
33   *
34   * @since 1.8.0
35   */
36  @Singleton
37  @Named( Nexus2ChecksumExtractor.NAME )
38  public class Nexus2ChecksumExtractor
39          extends ChecksumExtractor
40  {
41      public static final String NAME = "nexus2";
42  
43      @Override
44      public Map<String, String> extractChecksums( HttpResponse response )
45      {
46          // Nexus-style, ETag: "{SHA1{d40d68ba1f88d8e9b0040f175a6ff41928abd5e7}}"
47          Header header = response.getFirstHeader( HttpHeaders.ETAG );
48          String etag = header != null ? header.getValue() : null;
49          if ( etag != null )
50          {
51              int start = etag.indexOf( "SHA1{" ), end = etag.indexOf( "}", start + 5 );
52              if ( start >= 0 && end > start )
53              {
54                  return Collections.singletonMap( "SHA-1", etag.substring( start + 5, end ) );
55              }
56          }
57          return null;
58      }
59  }