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.HttpException;
michael@0: import ch.boye.httpclientandroidlib.HttpResponse;
michael@0: import ch.boye.httpclientandroidlib.HttpResponseInterceptor;
michael@0: import ch.boye.httpclientandroidlib.HttpStatus;
michael@0: import ch.boye.httpclientandroidlib.HttpVersion;
michael@0: import ch.boye.httpclientandroidlib.ProtocolVersion;
michael@0: import ch.boye.httpclientandroidlib.ProtocolException;
michael@0: 
michael@0: /**
michael@0:  * ResponseContent is the most important interceptor for outgoing responses.
michael@0:  * It is responsible for delimiting content length by adding
michael@0:  * <code>Content-Length</code> or <code>Transfer-Content</code> headers based
michael@0:  * on the properties of the enclosed entity and the protocol version.
michael@0:  * This interceptor is required for correct functioning of server side protocol
michael@0:  * processors.
michael@0:  *
michael@0:  * @since 4.0
michael@0:  */
michael@0: public class ResponseContent implements HttpResponseInterceptor {
michael@0: 
michael@0:     public ResponseContent() {
michael@0:         super();
michael@0:     }
michael@0: 
michael@0:     public void process(final HttpResponse response, final HttpContext context)
michael@0:             throws HttpException, IOException {
michael@0:         if (response == null) {
michael@0:             throw new IllegalArgumentException("HTTP response may not be null");
michael@0:         }
michael@0:         if (response.containsHeader(HTTP.TRANSFER_ENCODING)) {
michael@0:             throw new ProtocolException("Transfer-encoding header already present");
michael@0:         }
michael@0:         if (response.containsHeader(HTTP.CONTENT_LEN)) {
michael@0:             throw new ProtocolException("Content-Length header already present");
michael@0:         }
michael@0:         ProtocolVersion ver = response.getStatusLine().getProtocolVersion();
michael@0:         HttpEntity entity = response.getEntity();
michael@0:         if (entity != null) {
michael@0:             long len = entity.getContentLength();
michael@0:             if (entity.isChunked() && !ver.lessEquals(HttpVersion.HTTP_1_0)) {
michael@0:                 response.addHeader(HTTP.TRANSFER_ENCODING, HTTP.CHUNK_CODING);
michael@0:             } else if (len >= 0) {
michael@0:                 response.addHeader(HTTP.CONTENT_LEN, Long.toString(entity.getContentLength()));
michael@0:             }
michael@0:             // Specify a content type if known
michael@0:             if (entity.getContentType() != null && !response.containsHeader(
michael@0:                     HTTP.CONTENT_TYPE )) {
michael@0:                 response.addHeader(entity.getContentType());
michael@0:             }
michael@0:             // Specify a content encoding if known
michael@0:             if (entity.getContentEncoding() != null && !response.containsHeader(
michael@0:                     HTTP.CONTENT_ENCODING)) {
michael@0:                 response.addHeader(entity.getContentEncoding());
michael@0:             }
michael@0:         } else {
michael@0:             int status = response.getStatusLine().getStatusCode();
michael@0:             if (status != HttpStatus.SC_NO_CONTENT
michael@0:                     && status != HttpStatus.SC_NOT_MODIFIED
michael@0:                     && status != HttpStatus.SC_RESET_CONTENT) {
michael@0:                 response.addHeader(HTTP.CONTENT_LEN, "0");
michael@0:             }
michael@0:         }
michael@0:     }
michael@0: 
michael@0: }