/*
* $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
* <http://www.apache.org/>.
*
*/
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.
* <p>
* This strategy conforms to the entity transfer rules outlined in
* <a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec4.4">Section 4.4</a>,
* <a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.6">Section 3.6</a>,
* <a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.41">Section 14.41</a>
* and <a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec14.13">Section 14.13</a>
* of <a href="http://www.w3.org/Protocols/rfc2616/rfc2616.txt">RFC 2616</a>, but is lenient
* about unsupported transfer codecs and malformed content-length headers.
* </p>
* <h>4.4 Message Length</h>
* <p>
* 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):
* </p>
* <p>
* 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.
* </p>
* <p>
* 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.
* </p>
* <p>
* 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
* </p>
* <pre>
* 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.
* </pre>
* <p>
* 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.
* </p>
* <pre>
* 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.
* </pre>
* <p>
* 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.)
* </p>
* <p>
* 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.
* </p>
* <p>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.
* </p>
* <h>3.6 Transfer Codings</h>
* <p>
* 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.
* </p>
* <pre>
* transfer-coding = "chunked" | transfer-extension
* transfer-extension = token *( ";" parameter )
* </pre>
* <p>
* Parameters are in the form of attribute/value pairs.
* </p>
* <pre>
* parameter = attribute "=" value
* attribute = token
* value = token | quoted-string
* </pre>
* <p>
* 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).
* </p>
* <p>
* 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).
* </p>
* <h>14.41 Transfer-Encoding</h>
* <p>
* 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.
* </p>
* <pre>
* Transfer-Encoding = "Transfer-Encoding" ":" 1#transfer-coding
* </pre>
* <p>
* 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.
* </p>
* <h>14.13 Content-Length</h>
* <p>
* 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.
* </p>
* <pre>
* Content-Length = "Content-Length" ":" 1*DIGIT
* </pre>
* <p>
* 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.
* </p>
*
* @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
*
* @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;
}
}
}