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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  package org.eclipse.aether.transport.http;
20  
21  import javax.inject.Named;
22  import javax.inject.Singleton;
23  
24  import java.util.Collections;
25  import java.util.Map;
26  
27  import org.apache.http.Header;
28  import org.apache.http.HttpHeaders;
29  import org.apache.http.HttpResponse;
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 extends ChecksumExtractor {
39      public static final String NAME = "nexus2";
40  
41      @Override
42      public Map<String, String> extractChecksums(HttpResponse response) {
43          // Nexus-style, ETag: "{SHA1{d40d68ba1f88d8e9b0040f175a6ff41928abd5e7}}"
44          Header header = response.getFirstHeader(HttpHeaders.ETAG);
45          String etag = header != null ? header.getValue() : null;
46          if (etag != null) {
47              int start = etag.indexOf("SHA1{"), end = etag.indexOf("}", start + 5);
48              if (start >= 0 && end > start) {
49                  return Collections.singletonMap("SHA-1", etag.substring(start + 5, end));
50              }
51          }
52          return null;
53      }
54  }