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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.HeaderElement;
32  import org.apache.http.HttpException;
33  import org.apache.http.HttpMessage;
34  import org.apache.http.ParseException;
35  import org.apache.http.ProtocolException;
36  import org.apache.http.annotation.Immutable;
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 lax implementation of the content length strategy. This class will ignore
43   * unrecognized transfer encodings and malformed <code>Content-Length</code>
44   * header values.
45   * <p/>
46   * This class recognizes "chunked" and "identitiy" transfer-coding only.
47   *
48   * @since 4.0
49   */
50  @Immutable
51  public class LaxContentLengthStrategy implements ContentLengthStrategy {
52  
53      public static final LaxContentLengthStrategy INSTANCE = new LaxContentLengthStrategy();
54  
55      private final int implicitLen;
56  
57      /**
58       * Creates <tt>LaxContentLengthStrategy</tt> instance with the given length used per default
59       * when content length is not explicitly specified in the message.
60       *
61       * @param implicitLen implicit content length.
62       *
63       * @since 4.2
64       */
65      public LaxContentLengthStrategy(final int implicitLen) {
66          super();
67          this.implicitLen = implicitLen;
68      }
69  
70      /**
71       * Creates <tt>LaxContentLengthStrategy</tt> instance. {@link ContentLengthStrategy#IDENTITY}
72       * is used per default when content length is not explicitly specified in the message.
73       */
74      public LaxContentLengthStrategy() {
75          this(IDENTITY);
76      }
77  
78      public long determineLength(final HttpMessage message) throws HttpException {
79          Args.notNull(message, "HTTP message");
80  
81          final Header transferEncodingHeader = message.getFirstHeader(HTTP.TRANSFER_ENCODING);
82          // We use Transfer-Encoding if present and ignore Content-Length.
83          // RFC2616, 4.4 item number 3
84          if (transferEncodingHeader != null) {
85              final HeaderElement[] encodings;
86              try {
87                  encodings = transferEncodingHeader.getElements();
88              } catch (final ParseException px) {
89                  throw new ProtocolException
90                      ("Invalid Transfer-Encoding header value: " +
91                       transferEncodingHeader, px);
92              }
93              // The chunked encoding must be the last one applied RFC2616, 14.41
94              final int len = encodings.length;
95              if (HTTP.IDENTITY_CODING.equalsIgnoreCase(transferEncodingHeader.getValue())) {
96                  return IDENTITY;
97              } else if ((len > 0) && (HTTP.CHUNK_CODING.equalsIgnoreCase(
98                      encodings[len - 1].getName()))) {
99                  return CHUNKED;
100             } else {
101                 return IDENTITY;
102             }
103         }
104         final Header contentLengthHeader = message.getFirstHeader(HTTP.CONTENT_LEN);
105         if (contentLengthHeader != null) {
106             long contentlen = -1;
107             final Header[] headers = message.getHeaders(HTTP.CONTENT_LEN);
108             for (int i = headers.length - 1; i >= 0; i--) {
109                 final Header header = headers[i];
110                 try {
111                     contentlen = Long.parseLong(header.getValue());
112                     break;
113                 } catch (final NumberFormatException ignore) {
114                 }
115                 // See if we can have better luck with another header, if present
116             }
117             if (contentlen >= 0) {
118                 return contentlen;
119             } else {
120                 return IDENTITY;
121             }
122         }
123         return this.implicitLen;
124     }
125 
126 }