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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  package org.apache.hc.client5.http.impl.cache;
28  
29  import org.apache.hc.client5.http.cache.RequestCacheControl;
30  import org.apache.hc.core5.http.HttpRequest;
31  import org.apache.hc.core5.http.HttpVersion;
32  import org.apache.hc.core5.http.Method;
33  import org.apache.hc.core5.http.ProtocolVersion;
34  import org.slf4j.Logger;
35  import org.slf4j.LoggerFactory;
36  
37  /**
38   * Determines if an HttpRequest is allowed to be served from the cache.
39   */
40  class CacheableRequestPolicy {
41  
42      private static final Logger LOG = LoggerFactory.getLogger(CacheableRequestPolicy.class);
43  
44      /**
45       * Determines if an HttpRequest can be served from the cache.
46       *
47       * @param request
48       *            an HttpRequest
49       * @return boolean Is it possible to serve this request from cache
50       */
51      public boolean canBeServedFromCache(final RequestCacheControl cacheControl, final HttpRequest request) {
52          final String method = request.getMethod();
53  
54          final ProtocolVersion pv = request.getVersion() != null ? request.getVersion() : HttpVersion.DEFAULT;
55          if (HttpVersion.HTTP_1_1.compareToVersion(pv) != 0) {
56              LOG.debug("non-HTTP/1.1 request cannot be served from cache");
57              return false;
58          }
59  
60          if (!Method.GET.isSame(method) && !Method.HEAD.isSame(method)) {
61              if (LOG.isDebugEnabled()) {
62                  LOG.debug("{} request cannot be served from cache", method);
63              }
64              return false;
65          }
66  
67          if (cacheControl.isNoStore()) {
68              LOG.debug("Request with no-store cannot be served from cache");
69              return false;
70          }
71          if (cacheControl.isNoCache()) {
72              LOG.debug("Request with no-cache cannot be served from cache");
73              return false;
74          }
75          LOG.debug("Request can be served from cache");
76          return true;
77      }
78  
79  }