/*
* Copyright 2016 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:
*
* 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.
*/
package io.netty.handler.codec.http2;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelDuplexHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPromise;
import io.netty.handler.codec.UnsupportedMessageTypeException;
import io.netty.handler.codec.http.HttpServerUpgradeHandler.UpgradeEvent;
import io.netty.handler.codec.http2.Http2Connection.Endpoint;
import io.netty.util.ReferenceCountUtil;
import io.netty.util.internal.UnstableApi;
import static io.netty.handler.codec.http2.Http2CodecUtil.isOutboundStream;
import static io.netty.handler.codec.http2.Http2CodecUtil.isStreamIdValid;
import static io.netty.handler.logging.LogLevel.INFO;
/**
* An HTTP/2 handler that maps HTTP/2 frames to {@link Http2Frame} objects and vice versa. For every incoming HTTP/2
* frame a {@link Http2Frame} object is created and propagated via {@link #channelRead}. Outbound {@link Http2Frame}
* objects received via {@link #write} are converted to the HTTP/2 wire format.
*
* <p>A change in stream state is propagated through the channel pipeline as a user event via
* {@link Http2StreamStateEvent} objects. When a HTTP/2 stream first becomes active a {@link Http2StreamActiveEvent}
* and when it gets closed a {@link Http2StreamClosedEvent} is emitted.
*
* <p>Server-side HTTP to HTTP/2 upgrade is supported in conjunction with {@link Http2ServerUpgradeCodec}; the necessary
* HTTP-to-HTTP/2 conversion is performed automatically.
*
* <p><em>This API is very immature.</em> The Http2Connection-based API is currently preferred over
* this API. This API is targeted to eventually replace or reduce the need for the Http2Connection-based API.
*
* <h3>Opening and Closing Streams</h3>
*
* <p>When the remote side opens a new stream, the frame codec first emits a {@link Http2StreamActiveEvent} with the
* stream identifier set.
* <pre>
* {@link Http2FrameCodec} {@link Http2MultiplexCodec}
* + +
* | Http2StreamActiveEvent(streamId=3, headers=null) |
* +------------------------------------------------------------->
* | |
* | Http2HeadersFrame(streamId=3) |
* +------------------------------------------------------------->
* | |
* + +
* </pre>
*
* <p>When a stream is closed either due to a reset frame by the remote side, or due to both sides having sent frames
* with the END_STREAM flag, then the frame codec emits a {@link Http2StreamClosedEvent}.
* <pre>
* {@link Http2FrameCodec} {@link Http2MultiplexCodec}
* + +
* | Http2StreamClosedEvent(streamId=3) |
* +--------------------------------------------------------->
* | |
* + +
* </pre>
*
* <p>When the local side wants to close a stream, it has to write a {@link Http2ResetFrame} to which the frame codec
* will respond to with a {@link Http2StreamClosedEvent}.
* <pre>
* {@link Http2FrameCodec} {@link Http2MultiplexCodec}
* + +
* | Http2ResetFrame(streamId=3) |
* <---------------------------------------------------------+
* | |
* | Http2StreamClosedEvent(streamId=3) |
* +--------------------------------------------------------->
* | |
* + +
* </pre>
*
* <p>Opening an outbound/local stream works by first sending the frame codec a {@link Http2HeadersFrame} with no
* stream identifier set (such that {@link Http2CodecUtil#isStreamIdValid} returns {@code false}). If opening the stream
* was successful, the frame codec responds with a {@link Http2StreamActiveEvent} that contains the stream's new
* identifier as well as the <em>same</em> {@link Http2HeadersFrame} object that opened the stream.
* <pre>
* {@link Http2FrameCodec} {@link Http2MultiplexCodec}
* + +
* | Http2HeadersFrame(streamId=-1) |
* <-----------------------------------------------------------------------------------------------+
* | |
* | Http2StreamActiveEvent(streamId=2, headers=Http2HeadersFrame(streamId=-1)) |
* +----------------------------------------------------------------------------------------------->
* | |
* + +
* </pre>
*/
@UnstableApi
public class Http2FrameCodec extends ChannelDuplexHandler {
private static final Http2FrameLogger HTTP2_FRAME_LOGGER = new Http2FrameLogger(INFO, Http2FrameCodec.class);
private final Http2ConnectionHandler http2Handler;
private final boolean server;
private ChannelHandlerContext ctx;
private ChannelHandlerContext http2HandlerCtx;
/**
* Construct a new handler.
*
* @param server {@code true} this is a server
*/
public Http2FrameCodec(boolean server) {
this(server, HTTP2_FRAME_LOGGER);
}
/**
* Construct a new handler.
*
* @param server {@code true} this is a server
*/
public Http2FrameCodec(boolean server, Http2FrameLogger frameLogger) {
this(server, new DefaultHttp2FrameWriter(), frameLogger, new Http2Settings());
}
// Visible for testing
Http2FrameCodec(boolean server, Http2FrameWriter frameWriter, Http2FrameLogger frameLogger,
Http2Settings initialSettings) {
// TODO(scott): configure maxReservedStreams when API is more finalized.
Http2Connection connection = new DefaultHttp2Connection(server);
frameWriter = new Http2OutboundFrameLogger(frameWriter, frameLogger);
Http2ConnectionEncoder encoder = new DefaultHttp2ConnectionEncoder(connection, frameWriter);
Long maxHeaderListSize = initialSettings.maxHeaderListSize();
Http2FrameReader frameReader = new DefaultHttp2FrameReader(maxHeaderListSize == null ?
new DefaultHttp2HeadersDecoder(true) :
new DefaultHttp2HeadersDecoder(true, maxHeaderListSize));
Http2FrameReader reader = new Http2InboundFrameLogger(frameReader, frameLogger);
Http2ConnectionDecoder decoder = new DefaultHttp2ConnectionDecoder(connection, encoder, reader);
decoder.frameListener(new FrameListener());
http2Handler = new InternalHttp2ConnectionHandler(decoder, encoder, initialSettings);
http2Handler.connection().addListener(new ConnectionListener());
this.server = server;
}
Http2ConnectionHandler connectionHandler() {
return http2Handler;
}
/**
* Load any dependencies.
*/
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
this.ctx = ctx;
ctx.pipeline().addBefore(ctx.executor(), ctx.name(), null, http2Handler);
http2HandlerCtx = ctx.pipeline().context(http2Handler);
}
/**
* Clean up any dependencies.
*/
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
ctx.pipeline().remove(http2Handler);
}
/**
* Handles the cleartext HTTP upgrade event. If an upgrade occurred, sends a simple response via
* HTTP/2 on stream 1 (the stream specifically reserved for cleartext HTTP upgrade).
*/
@Override
public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
if (!(evt instanceof UpgradeEvent)) {
super.userEventTriggered(ctx, evt);
return;
}
UpgradeEvent upgrade = (UpgradeEvent) evt;
ctx.fireUserEventTriggered(upgrade.retain());
try {
Http2Stream stream = http2Handler.connection().stream(Http2CodecUtil.HTTP_UPGRADE_STREAM_ID);
// TODO: improve handler/stream lifecycle so that stream isn't active before handler added.
// The stream was already made active, but ctx may have been null so it wasn't initialized.
// https://github.com/netty/netty/issues/4942
new ConnectionListener().onStreamActive(stream);
upgrade.upgradeRequest().headers().setInt(
HttpConversionUtil.ExtensionHeaderNames.STREAM_ID.text(), Http2CodecUtil.HTTP_UPGRADE_STREAM_ID);
new InboundHttpToHttp2Adapter(http2Handler.connection(), http2Handler.decoder().frameListener())
.channelRead(ctx, upgrade.upgradeRequest().retain());
} finally {
upgrade.release();
}
}
// Override this to signal it will never throw an exception.
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
ctx.fireExceptionCaught(cause);
}
/**
* Processes all {@link Http2Frame}s. {@link Http2StreamFrame}s may only originate in child
* streams.
*/
@Override
public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) {
try {
if (msg instanceof Http2WindowUpdateFrame) {
Http2WindowUpdateFrame frame = (Http2WindowUpdateFrame) msg;
consumeBytes(frame.streamId(), frame.windowSizeIncrement(), promise);
} else if (msg instanceof Http2StreamFrame) {
writeStreamFrame((Http2StreamFrame) msg, promise);
} else if (msg instanceof Http2GoAwayFrame) {
writeGoAwayFrame((Http2GoAwayFrame) msg, promise);
} else {
throw new UnsupportedMessageTypeException(msg);
}
} finally {
ReferenceCountUtil.release(msg);
}
}
private void consumeBytes(int streamId, int bytes, ChannelPromise promise) {
try {
Http2Stream stream = http2Handler.connection().stream(streamId);
http2Handler.connection().local().flowController()
.consumeBytes(stream, bytes);
promise.setSuccess();
} catch (Throwable t) {
promise.setFailure(t);
}
}
private void writeGoAwayFrame(Http2GoAwayFrame frame, ChannelPromise promise) {
if (frame.lastStreamId() > -1) {
throw new IllegalArgumentException("Last stream id must not be set on GOAWAY frame");
}
int lastStreamCreated = http2Handler.connection().remote().lastStreamCreated();
int lastStreamId = lastStreamCreated + frame.extraStreamIds() * 2;
// Check if the computation overflowed.
if (lastStreamId < lastStreamCreated) {
lastStreamId = Integer.MAX_VALUE;
}
http2Handler.goAway(
http2HandlerCtx, lastStreamId, frame.errorCode(), frame.content().retain(), promise);
}
private void writeStreamFrame(Http2StreamFrame frame, ChannelPromise promise) {
if (frame instanceof Http2DataFrame) {
Http2DataFrame dataFrame = (Http2DataFrame) frame;
http2Handler.encoder().writeData(http2HandlerCtx, frame.streamId(), dataFrame.content().retain(),
dataFrame.padding(), dataFrame.isEndStream(), promise);
} else if (frame instanceof Http2HeadersFrame) {
writeHeadersFrame((Http2HeadersFrame) frame, promise);
} else if (frame instanceof Http2ResetFrame) {
Http2ResetFrame rstFrame = (Http2ResetFrame) frame;
http2Handler.resetStream(http2HandlerCtx, frame.streamId(), rstFrame.errorCode(), promise);
} else {
throw new UnsupportedMessageTypeException(frame);
}
}
private void writeHeadersFrame(Http2HeadersFrame headersFrame, ChannelPromise promise) {
int streamId = headersFrame.streamId();
if (!isStreamIdValid(streamId)) {
final Endpoint<Http2LocalFlowController> localEndpoint = http2Handler.connection().local();
streamId = localEndpoint.incrementAndGetNextStreamId();
try {
// Try to create a stream in OPEN state before writing headers, to catch errors on stream creation
// early on i.e. max concurrent streams limit reached, stream id exhaustion, etc.
localEndpoint.createStream(streamId, false);
} catch (Http2Exception e) {
promise.setFailure(e);
return;
}
ctx.fireUserEventTriggered(new Http2StreamActiveEvent(streamId, headersFrame));
}
http2Handler.encoder().writeHeaders(http2HandlerCtx, streamId, headersFrame.headers(),
headersFrame.padding(), headersFrame.isEndStream(), promise);
}
private final class ConnectionListener extends Http2ConnectionAdapter {
@Override
public void onStreamActive(Http2Stream stream) {
if (ctx == null) {
// UPGRADE stream is active before handlerAdded().
return;
}
if (isOutboundStream(server, stream.id())) {
// Creation of outbound streams is notified in writeHeadersFrame().
return;
}
ctx.fireUserEventTriggered(new Http2StreamActiveEvent(stream.id()));
}
@Override
public void onStreamClosed(Http2Stream stream) {
ctx.fireUserEventTriggered(new Http2StreamClosedEvent(stream.id()));
}
@Override
public void onGoAwayReceived(final int lastStreamId, long errorCode, ByteBuf debugData) {
ctx.fireChannelRead(new DefaultHttp2GoAwayFrame(lastStreamId, errorCode, debugData.retain()));
}
}
private static final class InternalHttp2ConnectionHandler extends Http2ConnectionHandler {
InternalHttp2ConnectionHandler(Http2ConnectionDecoder decoder, Http2ConnectionEncoder encoder,
Http2Settings initialSettings) {
super(decoder, encoder, initialSettings);
}
@Override
protected void onStreamError(ChannelHandlerContext ctx, Throwable cause,
Http2Exception.StreamException http2Ex) {
try {
Http2Stream stream = connection().stream(http2Ex.streamId());
if (stream == null) {
return;
}
ctx.fireExceptionCaught(http2Ex);
} finally {
super.onStreamError(ctx, cause, http2Ex);
}
}
}
private static final class FrameListener extends Http2FrameAdapter {
@Override
public void onRstStreamRead(ChannelHandlerContext ctx, int streamId, long errorCode) {
Http2ResetFrame rstFrame = new DefaultHttp2ResetFrame(errorCode);
rstFrame.streamId(streamId);
ctx.fireChannelRead(rstFrame);
}
@Override
public void onHeadersRead(ChannelHandlerContext ctx, int streamId,
Http2Headers headers, int streamDependency, short weight, boolean
exclusive, int padding, boolean endStream) {
onHeadersRead(ctx, streamId, headers, padding, endStream);
}
@Override
public void onHeadersRead(ChannelHandlerContext ctx, int streamId, Http2Headers headers,
int padding, boolean endOfStream) {
Http2HeadersFrame headersFrame = new DefaultHttp2HeadersFrame(headers, endOfStream, padding);
headersFrame.streamId(streamId);
ctx.fireChannelRead(headersFrame);
}
@Override
public int onDataRead(ChannelHandlerContext ctx, int streamId, ByteBuf data, int padding,
boolean endOfStream) {
Http2DataFrame dataFrame = new DefaultHttp2DataFrame(data.retain(), endOfStream, padding);
dataFrame.streamId(streamId);
ctx.fireChannelRead(dataFrame);
// We return the bytes in bytesConsumed() once the stream channel consumed the bytes.
return 0;
}
}
}