f1db0b9014
Motivation: Fixes an IllegalReferenceCountException Modification: Retained the buffers so the encoder works correctly. Result: Fixes #11357
383 lines
15 KiB
Java
383 lines
15 KiB
Java
/*
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* Copyright 2012 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* https://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.handler.codec.http;
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import static java.util.Objects.requireNonNull;
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import io.netty.buffer.ByteBuf;
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import io.netty.buffer.ByteBufHolder;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.channel.embedded.EmbeddedChannel;
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import io.netty.handler.codec.DecoderResult;
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import io.netty.handler.codec.MessageToMessageCodec;
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import io.netty.util.ReferenceCountUtil;
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import io.netty.util.internal.StringUtil;
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import java.util.ArrayDeque;
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import java.util.List;
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import java.util.Queue;
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import static io.netty.handler.codec.http.HttpHeaderNames.*;
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/**
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* Encodes the content of the outbound {@link HttpResponse} and {@link HttpContent}.
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* The original content is replaced with the new content encoded by the
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* {@link EmbeddedChannel}, which is created by {@link #beginEncode(HttpResponse, String)}.
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* Once encoding is finished, the value of the <tt>'Content-Encoding'</tt> header
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* is set to the target content encoding, as returned by
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* {@link #beginEncode(HttpResponse, String)}.
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* Also, the <tt>'Content-Length'</tt> header is updated to the length of the
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* encoded content. If there is no supported or allowed encoding in the
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* corresponding {@link HttpRequest}'s {@code "Accept-Encoding"} header,
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* {@link #beginEncode(HttpResponse, String)} should return {@code null} so that
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* no encoding occurs (i.e. pass-through).
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* <p>
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* Please note that this is an abstract class. You have to extend this class
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* and implement {@link #beginEncode(HttpResponse, String)} properly to make
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* this class functional. For example, refer to the source code of
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* {@link HttpContentCompressor}.
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* <p>
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* This handler must be placed after {@link HttpObjectEncoder} in the pipeline
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* so that this handler can intercept HTTP responses before {@link HttpObjectEncoder}
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* converts them into {@link ByteBuf}s.
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*/
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public abstract class HttpContentEncoder extends MessageToMessageCodec<HttpRequest, HttpObject> {
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private enum State {
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PASS_THROUGH,
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AWAIT_HEADERS,
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AWAIT_CONTENT
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}
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private static final CharSequence ZERO_LENGTH_HEAD = "HEAD";
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private static final CharSequence ZERO_LENGTH_CONNECT = "CONNECT";
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private static final int CONTINUE_CODE = HttpResponseStatus.CONTINUE.code();
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private final Queue<CharSequence> acceptEncodingQueue = new ArrayDeque<>();
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private EmbeddedChannel encoder;
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private State state = State.AWAIT_HEADERS;
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@Override
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public boolean acceptOutboundMessage(Object msg) throws Exception {
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return msg instanceof HttpContent || msg instanceof HttpResponse;
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}
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@Override
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protected void decode(ChannelHandlerContext ctx, HttpRequest msg) throws Exception {
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CharSequence acceptEncoding;
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List<String> acceptEncodingHeaders = msg.headers().getAll(ACCEPT_ENCODING);
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switch (acceptEncodingHeaders.size()) {
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case 0:
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acceptEncoding = HttpContentDecoder.IDENTITY;
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break;
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case 1:
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acceptEncoding = acceptEncodingHeaders.get(0);
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break;
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default:
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// Multiple message-header fields https://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2
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acceptEncoding = StringUtil.join(",", acceptEncodingHeaders);
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break;
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}
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HttpMethod method = msg.method();
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if (HttpMethod.HEAD.equals(method)) {
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acceptEncoding = ZERO_LENGTH_HEAD;
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} else if (HttpMethod.CONNECT.equals(method)) {
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acceptEncoding = ZERO_LENGTH_CONNECT;
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}
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acceptEncodingQueue.add(acceptEncoding);
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ctx.fireChannelRead(ReferenceCountUtil.retain(msg));
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}
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@Override
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protected void encode(ChannelHandlerContext ctx, HttpObject msg, List<Object> out) throws Exception {
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final boolean isFull = msg instanceof HttpResponse && msg instanceof LastHttpContent;
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switch (state) {
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case AWAIT_HEADERS: {
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ensureHeaders(msg);
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assert encoder == null;
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final HttpResponse res = (HttpResponse) msg;
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final int code = res.status().code();
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final CharSequence acceptEncoding;
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if (code == CONTINUE_CODE) {
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// We need to not poll the encoding when response with CONTINUE as another response will follow
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// for the issued request. See https://github.com/netty/netty/issues/4079
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acceptEncoding = null;
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} else {
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// Get the list of encodings accepted by the peer.
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acceptEncoding = acceptEncodingQueue.poll();
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if (acceptEncoding == null) {
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throw new IllegalStateException("cannot send more responses than requests");
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}
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}
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/*
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* per rfc2616 4.3 Message Body
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* All 1xx (informational), 204 (no content), and 304 (not modified) responses MUST NOT include a
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* message-body. All other responses do include a message-body, although it MAY be of zero length.
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*
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* 9.4 HEAD
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* The HEAD method is identical to GET except that the server MUST NOT return a message-body
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* in the response.
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*
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* Also we should pass through HTTP/1.0 as transfer-encoding: chunked is not supported.
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*
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* See https://github.com/netty/netty/issues/5382
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*/
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if (isPassthru(res.protocolVersion(), code, acceptEncoding)) {
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if (isFull) {
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out.add(ReferenceCountUtil.retain(res));
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} else {
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out.add(ReferenceCountUtil.retain(res));
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// Pass through all following contents.
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state = State.PASS_THROUGH;
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}
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break;
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}
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if (isFull) {
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// Pass through the full response with empty content and continue waiting for the next resp.
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if (!((ByteBufHolder) res).content().isReadable()) {
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out.add(ReferenceCountUtil.retain(res));
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break;
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}
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}
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// Prepare to encode the content.
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final Result result = beginEncode(res, acceptEncoding.toString());
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// If unable to encode, pass through.
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if (result == null) {
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if (isFull) {
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out.add(ReferenceCountUtil.retain(res));
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} else {
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out.add(ReferenceCountUtil.retain(res));
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// Pass through all following contents.
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state = State.PASS_THROUGH;
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}
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break;
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}
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encoder = result.contentEncoder();
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// Encode the content and remove or replace the existing headers
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// so that the message looks like a decoded message.
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res.headers().set(HttpHeaderNames.CONTENT_ENCODING, result.targetContentEncoding());
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// Output the rewritten response.
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if (isFull) {
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// Convert full message into unfull one.
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HttpResponse newRes = new DefaultHttpResponse(res.protocolVersion(), res.status());
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newRes.headers().set(res.headers());
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out.add(newRes);
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ensureContent(res);
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encodeFullResponse(newRes, (HttpContent) res, out);
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break;
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} else {
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// Make the response chunked to simplify content transformation.
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res.headers().remove(HttpHeaderNames.CONTENT_LENGTH);
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res.headers().set(HttpHeaderNames.TRANSFER_ENCODING, HttpHeaderValues.CHUNKED);
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out.add(ReferenceCountUtil.retain(res));
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state = State.AWAIT_CONTENT;
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if (!(msg instanceof HttpContent)) {
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// only break out the switch statement if we have not content to process
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// See https://github.com/netty/netty/issues/2006
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break;
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}
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// Fall through to encode the content
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}
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}
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case AWAIT_CONTENT: {
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ensureContent(msg);
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if (encodeContent((HttpContent) msg, out)) {
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state = State.AWAIT_HEADERS;
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}
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break;
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}
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case PASS_THROUGH: {
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ensureContent(msg);
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out.add(ReferenceCountUtil.retain(msg));
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// Passed through all following contents of the current response.
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if (msg instanceof LastHttpContent) {
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state = State.AWAIT_HEADERS;
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}
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break;
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}
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}
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}
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private void encodeFullResponse(HttpResponse newRes, HttpContent content, List<Object> out) {
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int existingMessages = out.size();
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encodeContent(content, out);
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if (HttpUtil.isContentLengthSet(newRes)) {
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// adjust the content-length header
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int messageSize = 0;
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for (int i = existingMessages; i < out.size(); i++) {
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Object item = out.get(i);
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if (item instanceof HttpContent) {
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messageSize += ((HttpContent) item).content().readableBytes();
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}
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}
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HttpUtil.setContentLength(newRes, messageSize);
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} else {
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newRes.headers().set(HttpHeaderNames.TRANSFER_ENCODING, HttpHeaderValues.CHUNKED);
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}
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}
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private static boolean isPassthru(HttpVersion version, int code, CharSequence httpMethod) {
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return code < 200 || code == 204 || code == 304 ||
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(httpMethod == ZERO_LENGTH_HEAD || (httpMethod == ZERO_LENGTH_CONNECT && code == 200)) ||
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version == HttpVersion.HTTP_1_0;
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}
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private static void ensureHeaders(HttpObject msg) {
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if (!(msg instanceof HttpResponse)) {
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throw new IllegalStateException(
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"unexpected message type: " +
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msg.getClass().getName() + " (expected: " + HttpResponse.class.getSimpleName() + ')');
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}
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}
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private static void ensureContent(HttpObject msg) {
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if (!(msg instanceof HttpContent)) {
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throw new IllegalStateException(
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"unexpected message type: " +
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msg.getClass().getName() + " (expected: " + HttpContent.class.getSimpleName() + ')');
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}
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}
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private boolean encodeContent(HttpContent c, List<Object> out) {
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ByteBuf content = c.content();
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encode(content, out);
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if (c instanceof LastHttpContent) {
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finishEncode(out);
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LastHttpContent last = (LastHttpContent) c;
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// Generate an additional chunk if the decoder produced
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// the last product on closure,
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HttpHeaders headers = last.trailingHeaders();
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if (headers.isEmpty()) {
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out.add(LastHttpContent.EMPTY_LAST_CONTENT);
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} else {
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out.add(new ComposedLastHttpContent(headers, DecoderResult.SUCCESS));
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}
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return true;
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}
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return false;
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}
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/**
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* Prepare to encode the HTTP message content.
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*
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* @param httpResponse
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* the http response
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* @param acceptEncoding
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* the value of the {@code "Accept-Encoding"} header
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*
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* @return the result of preparation, which is composed of the determined
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* target content encoding and a new {@link EmbeddedChannel} that
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* encodes the content into the target content encoding.
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* {@code null} if {@code acceptEncoding} is unsupported or rejected
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* and thus the content should be handled as-is (i.e. no encoding).
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*/
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protected abstract Result beginEncode(HttpResponse httpResponse, String acceptEncoding) throws Exception;
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@Override
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public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
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cleanupSafely(ctx);
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super.handlerRemoved(ctx);
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}
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@Override
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public void channelInactive(ChannelHandlerContext ctx) throws Exception {
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cleanupSafely(ctx);
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super.channelInactive(ctx);
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}
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private void cleanup() {
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if (encoder != null) {
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// Clean-up the previous encoder if not cleaned up correctly.
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encoder.finishAndReleaseAll();
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encoder = null;
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}
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}
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private void cleanupSafely(ChannelHandlerContext ctx) {
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try {
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cleanup();
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} catch (Throwable cause) {
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// If cleanup throws any error we need to propagate it through the pipeline
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// so we don't fail to propagate pipeline events.
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ctx.fireExceptionCaught(cause);
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}
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}
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private void encode(ByteBuf in, List<Object> out) {
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// call retain here as it will call release after its written to the channel
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encoder.writeOutbound(in.retain());
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fetchEncoderOutput(out);
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}
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private void finishEncode(List<Object> out) {
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if (encoder.finish()) {
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fetchEncoderOutput(out);
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}
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encoder = null;
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}
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private void fetchEncoderOutput(List<Object> out) {
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for (;;) {
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ByteBuf buf = encoder.readOutbound();
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if (buf == null) {
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break;
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}
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if (!buf.isReadable()) {
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buf.release();
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continue;
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}
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out.add(new DefaultHttpContent(buf));
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}
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}
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public static final class Result {
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private final String targetContentEncoding;
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private final EmbeddedChannel contentEncoder;
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public Result(String targetContentEncoding, EmbeddedChannel contentEncoder) {
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requireNonNull(targetContentEncoding, "targetContentEncoding");
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requireNonNull(contentEncoder, "contentEncoder");
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this.targetContentEncoding = targetContentEncoding;
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this.contentEncoder = contentEncoder;
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}
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public String targetContentEncoding() {
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return targetContentEncoding;
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}
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public EmbeddedChannel contentEncoder() {
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return contentEncoder;
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}
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}
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}
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