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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.http.impl.entity;
29  
30  import org.apache.http.Header;
31  import org.apache.http.HttpException;
32  import org.apache.http.HttpMessage;
33  import org.apache.http.HttpVersion;
34  import org.apache.http.ProtocolException;
35  import org.apache.http.annotation.ThreadingBehavior;
36  import org.apache.http.annotation.Contract;
37  import org.apache.http.entity.ContentLengthStrategy;
38  import org.apache.http.protocol.HTTP;
39  import org.apache.http.util.Args;
40  
41  /**
42   * The strict implementation of the content length strategy. This class
43   * will throw {@link ProtocolException} if it encounters an unsupported
44   * transfer encoding or a malformed {@code Content-Length} header
45   * value.
46   * <p>
47   * This class recognizes "chunked" and "identitiy" transfer-coding only.
48   *
49   * @since 4.0
50   */
51  @Contract(threading = ThreadingBehavior.IMMUTABLE)
52  public class StrictContentLengthStrategy implements ContentLengthStrategy {
53  
54      public static final StrictContentLengthStrategy INSTANCE = new StrictContentLengthStrategy();
55  
56      private final int implicitLen;
57  
58      /**
59       * Creates {@code StrictContentLengthStrategy} instance with the given length used per default
60       * when content length is not explicitly specified in the message.
61       *
62       * @param implicitLen implicit content length.
63       *
64       * @since 4.2
65       */
66      public StrictContentLengthStrategy(final int implicitLen) {
67          super();
68          this.implicitLen = implicitLen;
69      }
70  
71      /**
72       * Creates {@code StrictContentLengthStrategy} instance. {@link ContentLengthStrategy#IDENTITY}
73       * is used per default when content length is not explicitly specified in the message.
74       */
75      public StrictContentLengthStrategy() {
76          this(IDENTITY);
77      }
78  
79      @Override
80      public long determineLength(final HttpMessage message) throws HttpException {
81          Args.notNull(message, "HTTP message");
82          // Although Transfer-Encoding is specified as a list, in practice
83          // it is either missing or has the single value "chunked". So we
84          // treat it as a single-valued header here.
85          final Header transferEncodingHeader = message.getFirstHeader(HTTP.TRANSFER_ENCODING);
86          if (transferEncodingHeader != null) {
87              final String s = transferEncodingHeader.getValue();
88              if (HTTP.CHUNK_CODING.equalsIgnoreCase(s)) {
89                  if (message.getProtocolVersion().lessEquals(HttpVersion.HTTP_1_0)) {
90                      throw new ProtocolException(
91                              "Chunked transfer encoding not allowed for " +
92                              message.getProtocolVersion());
93                  }
94                  return CHUNKED;
95              } else if (HTTP.IDENTITY_CODING.equalsIgnoreCase(s)) {
96                  return IDENTITY;
97              } else {
98                  throw new ProtocolException(
99                          "Unsupported transfer encoding: " + s);
100             }
101         }
102         final Header contentLengthHeader = message.getFirstHeader(HTTP.CONTENT_LEN);
103         if (contentLengthHeader != null) {
104             final String s = contentLengthHeader.getValue();
105             try {
106                 final long len = Long.parseLong(s);
107                 if (len < 0) {
108                     throw new ProtocolException("Negative content length: " + s);
109                 }
110                 return len;
111             } catch (final NumberFormatException e) {
112                 throw new ProtocolException("Invalid content length: " + s);
113             }
114         }
115         return this.implicitLen;
116     }
117 
118 }