/lib/src/org/apache/http/impl/entity/LaxContentLengthStrategy.java

  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
 28package org.apache.http.impl.entity;
 29
 30import org.apache.http.Header;
 31import org.apache.http.HeaderElement;
 32import org.apache.http.HttpException;
 33import org.apache.http.HttpMessage;
 34import org.apache.http.ParseException;
 35import org.apache.http.ProtocolException;
 36import org.apache.http.entity.ContentLengthStrategy;
 37import org.apache.http.params.HttpParams;
 38import org.apache.http.params.CoreProtocolPNames;
 39import org.apache.http.protocol.HTTP;
 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 if the {@link CoreProtocolPNames#STRICT_TRANSFER_ENCODING} 
 45 * parameter of the given message is not set or set to <code>false</code>. 
 46 * <p>
 47 * This class recognizes "chunked" and "identitiy" transfer-coding only.
 48 * <p>
 49 * The following parameters can be used to customize the behavior of this class: 
 50 * <ul>
 51 *  <li>{@link org.apache.http.params.CoreProtocolPNames#STRICT_TRANSFER_ENCODING}</li>
 52 * </ul>
 53 * 
 54 * @since 4.0
 55 */
 56public class LaxContentLengthStrategy implements ContentLengthStrategy {
 57
 58    public LaxContentLengthStrategy() {
 59        super();
 60    }
 61
 62    public long determineLength(final HttpMessage message) throws HttpException {
 63        if (message == null) {
 64            throw new IllegalArgumentException("HTTP message may not be null");
 65        }
 66
 67        HttpParams params = message.getParams(); 
 68        boolean strict = params.isParameterTrue(CoreProtocolPNames.STRICT_TRANSFER_ENCODING);
 69        
 70        Header transferEncodingHeader = message.getFirstHeader(HTTP.TRANSFER_ENCODING);
 71        Header contentLengthHeader = message.getFirstHeader(HTTP.CONTENT_LEN);
 72        // We use Transfer-Encoding if present and ignore Content-Length.
 73        // RFC2616, 4.4 item number 3
 74        if (transferEncodingHeader != null) {
 75            HeaderElement[] encodings = null;
 76            try {
 77                encodings = transferEncodingHeader.getElements();
 78            } catch (ParseException px) {
 79                throw new ProtocolException
 80                    ("Invalid Transfer-Encoding header value: " +
 81                     transferEncodingHeader, px);
 82            }
 83            if (strict) {
 84                // Currently only chunk and identity are supported
 85                for (int i = 0; i < encodings.length; i++) {
 86                    String encoding = encodings[i].getName();
 87                    if (encoding != null && encoding.length() > 0 
 88                        && !encoding.equalsIgnoreCase(HTTP.CHUNK_CODING)
 89                        && !encoding.equalsIgnoreCase(HTTP.IDENTITY_CODING)) {
 90                        throw new ProtocolException("Unsupported transfer encoding: " + encoding);
 91                    }
 92                }
 93            }
 94            // The chunked encoding must be the last one applied RFC2616, 14.41
 95            int len = encodings.length;
 96            if (HTTP.IDENTITY_CODING.equalsIgnoreCase(transferEncodingHeader.getValue())) {
 97                return IDENTITY;                            
 98            } else if ((len > 0) && (HTTP.CHUNK_CODING.equalsIgnoreCase(
 99                    encodings[len - 1].getName()))) { 
100                return CHUNKED;
101            } else {
102                if (strict) {
103                    throw new ProtocolException("Chunk-encoding must be the last one applied");
104                }
105                return IDENTITY;                            
106            }
107        } else if (contentLengthHeader != null) {
108            long contentlen = -1;
109            Header[] headers = message.getHeaders(HTTP.CONTENT_LEN);
110            if (strict && headers.length > 1) {
111                throw new ProtocolException("Multiple content length headers");
112            }
113            for (int i = headers.length - 1; i >= 0; i--) {
114                Header header = headers[i];
115                try {
116                    contentlen = Long.parseLong(header.getValue());
117                    break;
118                } catch (NumberFormatException e) {
119                    if (strict) {
120                        throw new ProtocolException("Invalid content length: " + header.getValue());
121                    }
122                }
123                // See if we can have better luck with another header, if present
124            }
125            if (contentlen >= 0) {
126                return contentlen;
127            } else {
128                return IDENTITY;
129            }
130        } else {
131            return IDENTITY;
132        }
133    }
134        
135}