/*
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//httpclient/src/java/org/apache/commons/httpclient/methods/ExpectContinueMethod.java,v 1.13 2004/05/08 10:12:08 olegk Exp $
* $Revision: 480424 $
* $Date: 2006-11-29 06:56:49 +0100 (Wed, 29 Nov 2006) $
*
* ====================================================================
*
* 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.commons.httpclient.methods;
import java.io.IOException;
import org.apache.commons.httpclient.HttpConnection;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.HttpMethodBase;
import org.apache.commons.httpclient.HttpState;
import org.apache.commons.httpclient.HttpVersion;
import org.apache.commons.httpclient.params.HttpMethodParams;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
This abstract class serves as a foundation for all HTTP methods
that support 'Expect: 100-continue' handshake.
The purpose of the 100 (Continue) status (refer to section 10.1.1
of the RFC 2616 for more details) is to allow a client that is
sending a request message with a request body to determine if the
origin server is willing to accept the request (based on the request
headers) before the client sends the request body. In some cases,
it might either be inappropriate or highly inefficient for the
client to send the body if the server will reject the message
without looking at the body.
'Expect: 100-continue' handshake should be used with caution,
as it may cause problems with HTTP servers and proxies that
do not support HTTP/1.1 protocol.
Author: Oleg Kalnichevski Since: 2.0beta1
/**
* <p>
* This abstract class serves as a foundation for all HTTP methods
* that support 'Expect: 100-continue' handshake.
* </p>
*
* <p>
* The purpose of the 100 (Continue) status (refer to section 10.1.1
* of the RFC 2616 for more details) is to allow a client that is
* sending a request message with a request body to determine if the
* origin server is willing to accept the request (based on the request
* headers) before the client sends the request body. In some cases,
* it might either be inappropriate or highly inefficient for the
* client to send the body if the server will reject the message
* without looking at the body.
* </p>
*
* <p>
* 'Expect: 100-continue' handshake should be used with caution,
* as it may cause problems with HTTP servers and proxies that
* do not support HTTP/1.1 protocol.
* </p>
*
* @author <a href="mailto:oleg@ural.ru">Oleg Kalnichevski</a>
*
* @since 2.0beta1
*/
public abstract class ExpectContinueMethod extends HttpMethodBase {
LOG object for this class. /** LOG object for this class. */
private static final Log LOG = LogFactory.getLog(ExpectContinueMethod.class);
No-arg constructor.
Since: 2.0
/**
* No-arg constructor.
*
* @since 2.0
*/
public ExpectContinueMethod() {
super();
}
Constructor specifying a URI.
Params: - uri – either an absolute or relative URI
Since: 2.0
/**
* Constructor specifying a URI.
*
* @param uri either an absolute or relative URI
*
* @since 2.0
*/
public ExpectContinueMethod(String uri) {
super(uri);
}
Returns true if the 'Expect: 100-Continue' handshake
is activated. The purpose of the 'Expect: 100-Continue'
handshake to allow a client that is sending a request message
with a request body to determine if the origin server is
willing to accept the request (based on the request headers)
before the client sends the request body.
See Also: Returns: true if 'Expect: 100-Continue' handshake is to
be used, false otherwise. Since: 2.0beta1 Deprecated: Use HttpMethodParams
/**
* <p>
* Returns <tt>true</tt> if the 'Expect: 100-Continue' handshake
* is activated. The purpose of the 'Expect: 100-Continue'
* handshake to allow a client that is sending a request message
* with a request body to determine if the origin server is
* willing to accept the request (based on the request headers)
* before the client sends the request body.
* </p>
*
* @return <tt>true</tt> if 'Expect: 100-Continue' handshake is to
* be used, <tt>false</tt> otherwise.
*
* @since 2.0beta1
*
* @deprecated Use {@link HttpMethodParams}
*
* @see #getParams()
* @see HttpMethodParams
* @see HttpMethodParams#USE_EXPECT_CONTINUE
*/
public boolean getUseExpectHeader() {
return getParams().getBooleanParameter(HttpMethodParams.USE_EXPECT_CONTINUE, false);
}
Activates 'Expect: 100-Continue' handshake. The purpose of
the 'Expect: 100-Continue' handshake to allow a client that is
sending a request message with a request body to determine if
the origin server is willing to accept the request (based on
the request headers) before the client sends the request body.
The use of the 'Expect: 100-continue' handshake can result in
noticable peformance improvement for entity enclosing requests
(such as POST and PUT) that require the target server's
authentication.
'Expect: 100-continue' handshake should be used with
caution, as it may cause problems with HTTP servers and
proxies that do not support HTTP/1.1 protocol.
Params: - value – boolean value
See Also: Since: 2.0beta1 Deprecated: Use HttpMethodParams
/**
* <p>
* Activates 'Expect: 100-Continue' handshake. The purpose of
* the 'Expect: 100-Continue' handshake to allow a client that is
* sending a request message with a request body to determine if
* the origin server is willing to accept the request (based on
* the request headers) before the client sends the request body.
* </p>
*
* <p>
* The use of the 'Expect: 100-continue' handshake can result in
* noticable peformance improvement for entity enclosing requests
* (such as POST and PUT) that require the target server's
* authentication.
* </p>
*
* <p>
* 'Expect: 100-continue' handshake should be used with
* caution, as it may cause problems with HTTP servers and
* proxies that do not support HTTP/1.1 protocol.
* </p>
*
* @param value boolean value
*
* @since 2.0beta1
*
* @deprecated Use {@link HttpMethodParams}
*
* @see #getParams()
* @see HttpMethodParams
* @see HttpMethodParams#USE_EXPECT_CONTINUE
*/
public void setUseExpectHeader(boolean value) {
getParams().setBooleanParameter(HttpMethodParams.USE_EXPECT_CONTINUE, value);
}
Returns true if there is a request body to be sent.
'Expect: 100-continue' handshake may not be used if request
body is not present
Returns: boolean Since: 2.0beta1
/**
* Returns <tt>true</tt> if there is a request body to be sent.
* 'Expect: 100-continue' handshake may not be used if request
* body is not present
*
* @return boolean
*
* @since 2.0beta1
*/
protected abstract boolean hasRequestContent();
Sets the Expect header if it has not already been set,
in addition to the "standard" set of headers.
Params: - state – the
state information associated with this method - conn – the
connection used to execute this HTTP method
Throws: - IOException – if an I/O (transport) error occurs. Some transport exceptions
can be recovered from.
- HttpException – if a protocol exception occurs. Usually protocol exceptions
cannot be recovered from.
/**
* Sets the <tt>Expect</tt> header if it has not already been set,
* in addition to the "standard" set of headers.
*
* @param state the {@link HttpState state} information associated with this method
* @param conn the {@link HttpConnection connection} used to execute
* this HTTP method
*
* @throws IOException if an I/O (transport) error occurs. Some transport exceptions
* can be recovered from.
* @throws HttpException if a protocol exception occurs. Usually protocol exceptions
* cannot be recovered from.
*/
protected void addRequestHeaders(HttpState state, HttpConnection conn)
throws IOException, HttpException {
LOG.trace("enter ExpectContinueMethod.addRequestHeaders(HttpState, HttpConnection)");
super.addRequestHeaders(state, conn);
// If the request is being retried, the header may already be present
boolean headerPresent = (getRequestHeader("Expect") != null);
// See if the expect header should be sent
// = HTTP/1.1 or higher
// = request body present
if (getParams().isParameterTrue(HttpMethodParams.USE_EXPECT_CONTINUE)
&& getEffectiveVersion().greaterEquals(HttpVersion.HTTP_1_1)
&& hasRequestContent())
{
if (!headerPresent) {
setRequestHeader("Expect", "100-continue");
}
} else {
if (headerPresent) {
removeRequestHeader("Expect");
}
}
}
}