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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.params.HttpParams;
39  import org.apache.http.params.CoreProtocolPNames;
40  import org.apache.http.protocol.HTTP;
41  
42  /**
43   * The lax implementation of the content length strategy. This class will ignore
44   * unrecognized transfer encodings and malformed <code>Content-Length</code>
45   * header values if the {@link CoreProtocolPNames#STRICT_TRANSFER_ENCODING}
46   * parameter of the given message is not set or set to <code>false</code>.
47   * <p>
48   * This class recognizes "chunked" and "identitiy" transfer-coding only.
49   * <p>
50   * The following parameters can be used to customize the behavior of this class:
51   * <ul>
52   *  <li>{@link org.apache.http.params.CoreProtocolPNames#STRICT_TRANSFER_ENCODING}</li>
53   * </ul>
54   *
55   * @since 4.0
56   */
57  @Immutable
58  public class LaxContentLengthStrategy implements ContentLengthStrategy {
59  
60      private final int implicitLen;
61      
62      /**
63       * Creates <tt>LaxContentLengthStrategy</tt> instance with the given length used per default
64       * when content length is not explicitly specified in the message.
65       * 
66       * @param implicitLen implicit content length.
67       * 
68       * @since 4.2
69       */
70      public LaxContentLengthStrategy(int implicitLen) {
71          super();
72          this.implicitLen = implicitLen;
73      }
74  
75      /**
76       * Creates <tt>LaxContentLengthStrategy</tt> instance. {@link ContentLengthStrategy#IDENTITY} 
77       * is used per default when content length is not explicitly specified in the message.
78       */
79      public LaxContentLengthStrategy() {
80          this(IDENTITY);
81      }
82  
83      public long determineLength(final HttpMessage message) throws HttpException {
84          if (message == null) {
85              throw new IllegalArgumentException("HTTP message may not be null");
86          }
87  
88          HttpParams params = message.getParams();
89          boolean strict = params.isParameterTrue(CoreProtocolPNames.STRICT_TRANSFER_ENCODING);
90  
91          Header transferEncodingHeader = message.getFirstHeader(HTTP.TRANSFER_ENCODING);
92          // We use Transfer-Encoding if present and ignore Content-Length.
93          // RFC2616, 4.4 item number 3
94          if (transferEncodingHeader != null) {
95              HeaderElement[] encodings = null;
96              try {
97                  encodings = transferEncodingHeader.getElements();
98              } catch (ParseException px) {
99                  throw new ProtocolException
100                     ("Invalid Transfer-Encoding header value: " +
101                      transferEncodingHeader, px);
102             }
103             if (strict) {
104                 // Currently only chunk and identity are supported
105                 for (int i = 0; i < encodings.length; i++) {
106                     String encoding = encodings[i].getName();
107                     if (encoding != null && encoding.length() > 0
108                         && !encoding.equalsIgnoreCase(HTTP.CHUNK_CODING)
109                         && !encoding.equalsIgnoreCase(HTTP.IDENTITY_CODING)) {
110                         throw new ProtocolException("Unsupported transfer encoding: " + encoding);
111                     }
112                 }
113             }
114             // The chunked encoding must be the last one applied RFC2616, 14.41
115             int len = encodings.length;
116             if (HTTP.IDENTITY_CODING.equalsIgnoreCase(transferEncodingHeader.getValue())) {
117                 return IDENTITY;
118             } else if ((len > 0) && (HTTP.CHUNK_CODING.equalsIgnoreCase(
119                     encodings[len - 1].getName()))) {
120                 return CHUNKED;
121             } else {
122                 if (strict) {
123                     throw new ProtocolException("Chunk-encoding must be the last one applied");
124                 }
125                 return IDENTITY;
126             }
127         }
128         Header contentLengthHeader = message.getFirstHeader(HTTP.CONTENT_LEN);
129         if (contentLengthHeader != null) {
130             long contentlen = -1;
131             Header[] headers = message.getHeaders(HTTP.CONTENT_LEN);
132             if (strict && headers.length > 1) {
133                 throw new ProtocolException("Multiple content length headers");
134             }
135             for (int i = headers.length - 1; i >= 0; i--) {
136                 Header header = headers[i];
137                 try {
138                     contentlen = Long.parseLong(header.getValue());
139                     break;
140                 } catch (NumberFormatException e) {
141                     if (strict) {
142                         throw new ProtocolException("Invalid content length: " + header.getValue());
143                     }
144                 }
145                 // See if we can have better luck with another header, if present
146             }
147             if (contentlen >= 0) {
148                 return contentlen;
149             } else {
150                 return IDENTITY;
151             }
152         }
153         return this.implicitLen;
154     }
155 
156 }