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/*
 * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/impl/entity/LaxContentLengthStrategy.java $
 * $Revision: 576073 $
 * $Date: 2007-09-16 03:53:13 -0700 (Sun, 16 Sep 2007) $
 *
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * .
 *
 */

package org.apache.http.impl.entity;

import org.apache.http.Header;
import org.apache.http.HeaderElement;
import org.apache.http.HttpException;
import org.apache.http.HttpMessage;
import org.apache.http.ParseException;
import org.apache.http.ProtocolException;
import org.apache.http.entity.ContentLengthStrategy;
import org.apache.http.params.HttpParams;
import org.apache.http.params.CoreProtocolPNames;
import org.apache.http.protocol.HTTP;

/**
 * The lax implementation of the content length strategy.
 * 

* This strategy conforms to the entity transfer rules outlined in * Section 4.4, * Section 3.6, * Section 14.41 * and Section 14.13 * of RFC 2616, but is lenient * about unsupported transfer codecs and malformed content-length headers. *

* 4.4 Message Length *

* The transfer-length of a message is the length of the message-body as it appears in the * message; that is, after any transfer-codings have been applied. When a message-body is * included with a message, the transfer-length of that body is determined by one of the * following (in order of precedence): *

*

* 1.Any response message which "MUST NOT" include a message-body (such as the 1xx, 204, * and 304 responses and any response to a HEAD request) is always terminated by the first * empty line after the header fields, regardless of the entity-header fields present in the * message. *

*

* 2.If a Transfer-Encoding header field (section 14.41) is present and has any value other * than "identity", then the transfer-length is defined by use of the "chunked" transfer- * coding (section 3.6), unless the message is terminated by closing the connection. *

*

* 3.If a Content-Length header field (section 14.13) is present, its decimal value in * OCTETs represents both the entity-length and the transfer-length. The Content-Length * header field MUST NOT be sent if these two lengths are different (i.e., if a * Transfer-Encoding *

*
 *    header field is present). If a message is received with both a
 *    Transfer-Encoding header field and a Content-Length header field,
 *    the latter MUST be ignored.
 * 
*

* 4.If the message uses the media type "multipart/byteranges", and the ransfer-length is not * otherwise specified, then this self- elimiting media type defines the transfer-length. * This media type UST NOT be used unless the sender knows that the recipient can arse it; the * presence in a request of a Range header with ultiple byte- range specifiers from a 1.1 * client implies that the lient can parse multipart/byteranges responses. *

*
 *     A range header might be forwarded by a 1.0 proxy that does not
 *     understand multipart/byteranges; in this case the server MUST
 *     delimit the message using methods defined in items 1,3 or 5 of
 *     this section.
 * 
*

* 5.By the server closing the connection. (Closing the connection cannot be used to indicate * the end of a request body, since that would leave no possibility for the server to send back * a response.) *

*

* For compatibility with HTTP/1.0 applications, HTTP/1.1 requests containing a message-body * MUST include a valid Content-Length header field unless the server is known to be HTTP/1.1 * compliant. If a request contains a message-body and a Content-Length is not given, the * server SHOULD respond with 400 (bad request) if it cannot determine the length of the * message, or with 411 (length required) if it wishes to insist on receiving a valid * Content-Length. *

*

All HTTP/1.1 applications that receive entities MUST accept the "chunked" transfer-coding * (section 3.6), thus allowing this mechanism to be used for messages when the message * length cannot be determined in advance. *

* 3.6 Transfer Codings *

* Transfer-coding values are used to indicate an encoding transformation that * has been, can be, or may need to be applied to an entity-body in order to ensure * "safe transport" through the network. This differs from a content coding in that * the transfer-coding is a property of the message, not of the original entity. *

*
 * transfer-coding         = "chunked" | transfer-extension
 * transfer-extension      = token *( ";" parameter )
 * 
*

* Parameters are in the form of attribute/value pairs. *

*
 * parameter               = attribute "=" value
 * attribute               = token
 * value                   = token | quoted-string
 * 
*

* All transfer-coding values are case-insensitive. HTTP/1.1 uses transfer-coding values in * the TE header field (section 14.39) and in the Transfer-Encoding header field (section 14.41). *

*

* Whenever a transfer-coding is applied to a message-body, the set of transfer-codings MUST * include "chunked", unless the message is terminated by closing the connection. When the * "chunked" transfer-coding is used, it MUST be the last transfer-coding applied to the * message-body. The "chunked" transfer-coding MUST NOT be applied more than once to a * message-body. These rules allow the recipient to determine the transfer-length of the * message (section 4.4). *

* 14.41 Transfer-Encoding *

* The Transfer-Encoding general-header field indicates what (if any) type of transformation has * been applied to the message body in order to safely transfer it between the sender and the * recipient. This differs from the content-coding in that the transfer-coding is a property of * the message, not of the entity. *

*
 *   Transfer-Encoding       = "Transfer-Encoding" ":" 1#transfer-coding
 * 
*

* If multiple encodings have been applied to an entity, the transfer- codings MUST be listed in * the order in which they were applied. Additional information about the encoding parameters * MAY be provided by other entity-header fields not defined by this specification. *

* 14.13 Content-Length *

* The Content-Length entity-header field indicates the size of the entity-body, in decimal * number of OCTETs, sent to the recipient or, in the case of the HEAD method, the size of * the entity-body that would have been sent had the request been a GET. *

*
 *   Content-Length    = "Content-Length" ":" 1*DIGIT
 * 
*

* Applications SHOULD use this field to indicate the transfer-length of the message-body, * unless this is prohibited by the rules in section 4.4. *

* * @author Oleg Kalnichevski * * @version $Revision: 576073 $ * * @since 4.0 */ public class LaxContentLengthStrategy implements ContentLengthStrategy { public LaxContentLengthStrategy() { super(); } public long determineLength(final HttpMessage message) throws HttpException { if (message == null) { throw new IllegalArgumentException("HTTP message may not be null"); } HttpParams params = message.getParams(); boolean strict = params.isParameterTrue(CoreProtocolPNames.STRICT_TRANSFER_ENCODING); Header transferEncodingHeader = message.getFirstHeader(HTTP.TRANSFER_ENCODING); Header contentLengthHeader = message.getFirstHeader(HTTP.CONTENT_LEN); // We use Transfer-Encoding if present and ignore Content-Length. // RFC2616, 4.4 item number 3 if (transferEncodingHeader != null) { HeaderElement[] encodings = null; try { encodings = transferEncodingHeader.getElements(); } catch (ParseException px) { throw new ProtocolException ("Invalid Transfer-Encoding header value: " + transferEncodingHeader, px); } if (strict) { // Currently only chunk and identity are supported for (int i = 0; i < encodings.length; i++) { String encoding = encodings[i].getName(); if (encoding != null && encoding.length() > 0 && !encoding.equalsIgnoreCase(HTTP.CHUNK_CODING) && !encoding.equalsIgnoreCase(HTTP.IDENTITY_CODING)) { throw new ProtocolException("Unsupported transfer encoding: " + encoding); } } } // The chunked encoding must be the last one applied RFC2616, 14.41 int len = encodings.length; if (HTTP.IDENTITY_CODING.equalsIgnoreCase(transferEncodingHeader.getValue())) { return IDENTITY; } else if ((len > 0) && (HTTP.CHUNK_CODING.equalsIgnoreCase( encodings[len - 1].getName()))) { return CHUNKED; } else { if (strict) { throw new ProtocolException("Chunk-encoding must be the last one applied"); } return IDENTITY; } } else if (contentLengthHeader != null) { long contentlen = -1; Header[] headers = message.getHeaders(HTTP.CONTENT_LEN); if (strict && headers.length > 1) { throw new ProtocolException("Multiple content length headers"); } for (int i = headers.length - 1; i >= 0; i--) { Header header = headers[i]; try { contentlen = Long.parseLong(header.getValue()); break; } catch (NumberFormatException e) { if (strict) { throw new ProtocolException("Invalid content length: " + header.getValue()); } } // See if we can have better luck with another header, if present } if (contentlen >= 0) { return contentlen; } else { return IDENTITY; } } else { return IDENTITY; } } }




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