/*
* ====================================================================
* 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.protocol;
import java.io.
IOException;
import org.apache.http.
HttpEntity;
import org.apache.http.
HttpException;
import org.apache.http.
HttpResponse;
import org.apache.http.
HttpResponseInterceptor;
import org.apache.http.
HttpStatus;
import org.apache.http.
HttpVersion;
import org.apache.http.
ProtocolException;
import org.apache.http.
ProtocolVersion;
import org.apache.http.annotation.
ThreadingBehavior;
import org.apache.http.annotation.
Contract;
import org.apache.http.util.
Args;
/**
* ResponseContent is the most important interceptor for outgoing responses.
* It is responsible for delimiting content length by adding
* {@code Content-Length} or {@code Transfer-Content} headers based
* on the properties of the enclosed entity and the protocol version.
* This interceptor is required for correct functioning of server side protocol
* processors.
*
* @since 4.0
*/
@
Contract(threading =
ThreadingBehavior.
IMMUTABLE)
public class
ResponseContent implements
HttpResponseInterceptor {
private final boolean
overwrite;
/**
* Default constructor. The {@code Content-Length} or {@code Transfer-Encoding}
* will cause the interceptor to throw {@link ProtocolException} if already present in the
* response message.
*/
public
ResponseContent() {
this(false);
}
/**
* Constructor that can be used to fine-tune behavior of this interceptor.
*
* @param overwrite If set to {@code true} the {@code Content-Length} and
* {@code Transfer-Encoding} headers will be created or updated if already present.
* If set to {@code false} the {@code Content-Length} and
* {@code Transfer-Encoding} headers will cause the interceptor to throw
* {@link ProtocolException} if already present in the response message.
*
* @since 4.2
*/
public
ResponseContent(final boolean
overwrite) {
super();
this.
overwrite =
overwrite;
}
/**
* Processes the response (possibly updating or inserting) Content-Length and Transfer-Encoding headers.
* @param response The HttpResponse to modify.
* @param context Unused.
* @throws ProtocolException If either the Content-Length or Transfer-Encoding headers are found.
* @throws IllegalArgumentException If the response is null.
*/
@
Override
public void
process(final
HttpResponse response, final
HttpContext context)
throws
HttpException,
IOException {
Args.
notNull(
response, "HTTP response");
if (this.
overwrite) {
response.
removeHeaders(
HTTP.
TRANSFER_ENCODING);
response.
removeHeaders(
HTTP.
CONTENT_LEN);
} else {
if (
response.
containsHeader(
HTTP.
TRANSFER_ENCODING)) {
throw new
ProtocolException("Transfer-encoding header already present");
}
if (
response.
containsHeader(
HTTP.
CONTENT_LEN)) {
throw new
ProtocolException("Content-Length header already present");
}
}
final
ProtocolVersion ver =
response.
getStatusLine().
getProtocolVersion();
final
HttpEntity entity =
response.
getEntity();
if (
entity != null) {
final long
len =
entity.
getContentLength();
if (
entity.
isChunked() && !
ver.
lessEquals(
HttpVersion.
HTTP_1_0)) {
response.
addHeader(
HTTP.
TRANSFER_ENCODING,
HTTP.
CHUNK_CODING);
} else if (
len >= 0) {
response.
addHeader(
HTTP.
CONTENT_LEN,
Long.
toString(
entity.
getContentLength()));
}
// Specify a content type if known
if (
entity.
getContentType() != null && !
response.
containsHeader(
HTTP.
CONTENT_TYPE )) {
response.
addHeader(
entity.
getContentType());
}
// Specify a content encoding if known
if (
entity.
getContentEncoding() != null && !
response.
containsHeader(
HTTP.
CONTENT_ENCODING)) {
response.
addHeader(
entity.
getContentEncoding());
}
} else {
final int
status =
response.
getStatusLine().
getStatusCode();
if (
status !=
HttpStatus.
SC_NO_CONTENT
&&
status !=
HttpStatus.
SC_NOT_MODIFIED
&&
status !=
HttpStatus.
SC_RESET_CONTENT) {
response.
addHeader(
HTTP.
CONTENT_LEN, "0");
}
}
}
}