HttpContentEncoder.java — netty Source File

Source Code

/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project 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:
 *
 *   https://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.
 */
package io.netty.handler.codec.http;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufHolder;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.embedded.EmbeddedChannel;
import io.netty.handler.codec.DecoderResult;
import io.netty.handler.codec.MessageToMessageCodec;
import io.netty.util.ReferenceCountUtil;
import io.netty.util.internal.ObjectUtil;
import io.netty.util.internal.StringUtil;

import java.util.ArrayDeque;
import java.util.List;
import java.util.Queue;

import static io.netty.handler.codec.http.HttpHeaderNames.*;

/**
 * Encodes the content of the outbound {@link HttpResponse} and {@link HttpContent}.
 * The original content is replaced with the new content encoded by the
 * {@link EmbeddedChannel}, which is created by {@link #beginEncode(HttpResponse, String)}.
 * Once encoding is finished, the value of the <tt>'Content-Encoding'</tt> header
 * is set to the target content encoding, as returned by
 * {@link #beginEncode(HttpResponse, String)}.
 * Also, the <tt>'Content-Length'</tt> header is updated to the length of the
 * encoded content.  If there is no supported or allowed encoding in the
 * corresponding {@link HttpRequest}'s {@code "Accept-Encoding"} header,
 * {@link #beginEncode(HttpResponse, String)} should return {@code null} so that
 * no encoding occurs (i.e. pass-through).
 * <p>
 * Please note that this is an abstract class.  You have to extend this class
 * and implement {@link #beginEncode(HttpResponse, String)} properly to make
 * this class functional.  For example, refer to the source code of
 * {@link HttpContentCompressor}.
 * <p>
 * This handler must be placed after {@link HttpObjectEncoder} in the pipeline
 * so that this handler can intercept HTTP responses before {@link HttpObjectEncoder}
 * converts them into {@link ByteBuf}s.
 */
public abstract class HttpContentEncoder extends MessageToMessageCodec<HttpRequest, HttpObject> {

    private enum State {
        PASS_THROUGH,
// ... (324 more lines)