michael@0: /*
michael@0:  * ====================================================================
michael@0:  * Licensed to the Apache Software Foundation (ASF) under one
michael@0:  * or more contributor license agreements.  See the NOTICE file
michael@0:  * distributed with this work for additional information
michael@0:  * regarding copyright ownership.  The ASF licenses this file
michael@0:  * to you under the Apache License, Version 2.0 (the
michael@0:  * "License"); you may not use this file except in compliance
michael@0:  * with the License.  You may obtain a copy of the License at
michael@0:  *
michael@0:  *   http://www.apache.org/licenses/LICENSE-2.0
michael@0:  *
michael@0:  * Unless required by applicable law or agreed to in writing,
michael@0:  * software distributed under the License is distributed on an
michael@0:  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
michael@0:  * KIND, either express or implied.  See the License for the
michael@0:  * specific language governing permissions and limitations
michael@0:  * under the License.
michael@0:  * ====================================================================
michael@0:  *
michael@0:  * This software consists of voluntary contributions made by many
michael@0:  * individuals on behalf of the Apache Software Foundation.  For more
michael@0:  * information on the Apache Software Foundation, please see
michael@0:  * <http://www.apache.org/>.
michael@0:  *
michael@0:  */
michael@0: 
michael@0: package ch.boye.httpclientandroidlib.protocol;
michael@0: 
michael@0: import java.io.IOException;
michael@0: 
michael@0: import ch.boye.httpclientandroidlib.HttpEntity;
michael@0: import ch.boye.httpclientandroidlib.HttpEntityEnclosingRequest;
michael@0: import ch.boye.httpclientandroidlib.HttpException;
michael@0: import ch.boye.httpclientandroidlib.HttpRequest;
michael@0: import ch.boye.httpclientandroidlib.HttpRequestInterceptor;
michael@0: import ch.boye.httpclientandroidlib.HttpVersion;
michael@0: import ch.boye.httpclientandroidlib.ProtocolVersion;
michael@0: import ch.boye.httpclientandroidlib.params.HttpProtocolParams;
michael@0: 
michael@0: /**
michael@0:  * RequestExpectContinue is responsible for enabling the 'expect-continue'
michael@0:  * handshake by adding <code>Expect</code> header. This interceptor is
michael@0:  * recommended for client side protocol processors.
michael@0:  * <p>
michael@0:  * The following parameters can be used to customize the behavior of this
michael@0:  * class:
michael@0:  * <ul>
michael@0:  *  <li>{@link ch.boye.httpclientandroidlib.params.CoreProtocolPNames#USE_EXPECT_CONTINUE}</li>
michael@0:  * </ul>
michael@0:  *
michael@0:  * @since 4.0
michael@0:  */
michael@0: public class RequestExpectContinue implements HttpRequestInterceptor {
michael@0: 
michael@0:     public RequestExpectContinue() {
michael@0:         super();
michael@0:     }
michael@0: 
michael@0:     public void process(final HttpRequest request, final HttpContext context)
michael@0:             throws HttpException, IOException {
michael@0:         if (request == null) {
michael@0:             throw new IllegalArgumentException("HTTP request may not be null");
michael@0:         }
michael@0:         if (request instanceof HttpEntityEnclosingRequest) {
michael@0:             HttpEntity entity = ((HttpEntityEnclosingRequest)request).getEntity();
michael@0:             // Do not send the expect header if request body is known to be empty
michael@0:             if (entity != null && entity.getContentLength() != 0) {
michael@0:                 ProtocolVersion ver = request.getRequestLine().getProtocolVersion();
michael@0:                 if (HttpProtocolParams.useExpectContinue(request.getParams())
michael@0:                         && !ver.lessEquals(HttpVersion.HTTP_1_0)) {
michael@0:                     request.addHeader(HTTP.EXPECT_DIRECTIVE, HTTP.EXPECT_CONTINUE);
michael@0:                 }
michael@0:             }
michael@0:         }
michael@0:     }
michael@0: 
michael@0: }