/*
* Copyright 2014 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.ChannelHandlerContext;
import io.netty.util.internal.UnstableApi;
/**
* An listener of HTTP/2 frames.
*/
@UnstableApi
public interface Http2FrameListener {
/**
* Handles an inbound {@code DATA} frame.
*
* @param ctx the context from the handler where the frame was read.
* @param streamId the subject stream for the frame.
* @param data payload buffer for the frame. This buffer will be released by the codec.
* @param padding additional bytes that should be added to obscure the true content size. Must be between 0 and
* 256 (inclusive).
* @param endOfStream Indicates whether this is the last frame to be sent from the remote endpoint for this stream.
* @return the number of bytes that have been processed by the application. The returned bytes are used by the
* inbound flow controller to determine the appropriate time to expand the inbound flow control window (i.e. send
* {@code WINDOW_UPDATE}). Returning a value equal to the length of {@code data} + {@code padding} will effectively
* opt-out of application-level flow control for this frame. Returning a value less than the length of {@code data}
* + {@code padding} will defer the returning of the processed bytes, which the application must later return via
* {@link Http2LocalFlowController#consumeBytes(Http2Stream, int)}. The returned value must
* be >= {@code 0} and <= {@code data.readableBytes()} + {@code padding}.
*/
int onDataRead(ChannelHandlerContext ctx, int streamId, ByteBuf data, int padding,
boolean endOfStream) throws Http2Exception;
/**
* Handles an inbound {@code HEADERS} frame.
* <p>
* Only one of the following methods will be called for each {@code HEADERS} frame sequence.
* One will be called when the {@code END_HEADERS} flag has been received.
* <ul>
* <li>{@link #onHeadersRead(ChannelHandlerContext, int, Http2Headers, int, boolean)}</li>
* <li>{@link #onHeadersRead(ChannelHandlerContext, int, Http2Headers, int, short, boolean, int, boolean)}</li>
* <li>{@link #onPushPromiseRead(ChannelHandlerContext, int, int, Http2Headers, int)}</li>
* </ul>
* <p>
* To say it another way; the {@link Http2Headers} will contain all of the headers
* for the current message exchange step (additional queuing is not necessary).
*
* @param ctx the context from the handler where the frame was read.
* @param streamId the subject stream for the frame.
* @param headers the received headers.
* @param padding additional bytes that should be added to obscure the true content size. Must be between 0 and
* 256 (inclusive).
* @param endOfStream Indicates whether this is the last frame to be sent from the remote endpoint
* for this stream.
*/
void onHeadersRead(ChannelHandlerContext ctx, int streamId, Http2Headers headers, int padding,
boolean endOfStream) throws Http2Exception;
/**
* Handles an inbound {@code HEADERS} frame with priority information specified.
* Only called if {@code END_HEADERS} encountered.
* <p>
* Only one of the following methods will be called for each {@code HEADERS} frame sequence.
* One will be called when the {@code END_HEADERS} flag has been received.
* <ul>
* <li>{@link #onHeadersRead(ChannelHandlerContext, int, Http2Headers, int, boolean)}</li>
* <li>{@link #onHeadersRead(ChannelHandlerContext, int, Http2Headers, int, short, boolean, int, boolean)}</li>
* <li>{@link #onPushPromiseRead(ChannelHandlerContext, int, int, Http2Headers, int)}</li>
* </ul>
* <p>
* To say it another way; the {@link Http2Headers} will contain all of the headers
* for the current message exchange step (additional queuing is not necessary).
*
* @param ctx the context from the handler where the frame was read.
* @param streamId the subject stream for the frame.
* @param headers the received headers.
* @param streamDependency the stream on which this stream depends, or 0 if dependent on the
* connection.
* @param weight the new weight for the stream.
* @param exclusive whether or not the stream should be the exclusive dependent of its parent.
* @param padding additional bytes that should be added to obscure the true content size. Must be between 0 and
* 256 (inclusive).
* @param endOfStream Indicates whether this is the last frame to be sent from the remote endpoint
* for this stream.
*/
void onHeadersRead(ChannelHandlerContext ctx, int streamId, Http2Headers headers,
int streamDependency, short weight, boolean exclusive, int padding, boolean endOfStream)
throws Http2Exception;
/**
* Handles an inbound {@code PRIORITY} frame.
* <p>
* Note that is it possible to have this method called and no stream object exist for either
* {@code streamId}, {@code streamDependency}, or both. This is because the {@code PRIORITY} frame can be
* sent/received when streams are in the {@code CLOSED} state.
*
* @param ctx the context from the handler where the frame was read.
* @param streamId the subject stream for the frame.
* @param streamDependency the stream on which this stream depends, or 0 if dependent on the
* connection.
* @param weight the new weight for the stream.
* @param exclusive whether or not the stream should be the exclusive dependent of its parent.
*/
void onPriorityRead(ChannelHandlerContext ctx, int streamId, int streamDependency,
short weight, boolean exclusive) throws Http2Exception;
/**
* Handles an inbound {@code RST_STREAM} frame.
*
* @param ctx the context from the handler where the frame was read.
* @param streamId the stream that is terminating.
* @param errorCode the error code identifying the type of failure.
*/
void onRstStreamRead(ChannelHandlerContext ctx, int streamId, long errorCode) throws Http2Exception;
/**
* Handles an inbound {@code SETTINGS} acknowledgment frame.
* @param ctx the context from the handler where the frame was read.
*/
void onSettingsAckRead(ChannelHandlerContext ctx) throws Http2Exception;
/**
* Handles an inbound {@code SETTINGS} frame.
*
* @param ctx the context from the handler where the frame was read.
* @param settings the settings received from the remote endpoint.
*/
void onSettingsRead(ChannelHandlerContext ctx, Http2Settings settings) throws Http2Exception;
/**
* Handles an inbound {@code PING} frame.
*
* @param ctx the context from the handler where the frame was read.
* @param data the payload of the frame. If this buffer needs to be retained by the listener
* they must make a copy.
*/
void onPingRead(ChannelHandlerContext ctx, ByteBuf data) throws Http2Exception;
/**
* Handles an inbound {@code PING} acknowledgment.
*
* @param ctx the context from the handler where the frame was read.
* @param data the payload of the frame. If this buffer needs to be retained by the listener
* they must make a copy.
*/
void onPingAckRead(ChannelHandlerContext ctx, ByteBuf data) throws Http2Exception;
/**
* Handles an inbound {@code PUSH_PROMISE} frame. Only called if {@code END_HEADERS} encountered.
* <p>
* Promised requests MUST be authoritative, cacheable, and safe.
* See <a href="https://tools.ietf.org/html/draft-ietf-httpbis-http2-17#section-8.2">[RFC http2], Section 8.2</a>.
* <p>
* Only one of the following methods will be called for each {@code HEADERS} frame sequence.
* One will be called when the {@code END_HEADERS} flag has been received.
* <ul>
* <li>{@link #onHeadersRead(ChannelHandlerContext, int, Http2Headers, int, boolean)}</li>
* <li>{@link #onHeadersRead(ChannelHandlerContext, int, Http2Headers, int, short, boolean, int, boolean)}</li>
* <li>{@link #onPushPromiseRead(ChannelHandlerContext, int, int, Http2Headers, int)}</li>
* </ul>
* <p>
* To say it another way; the {@link Http2Headers} will contain all of the headers
* for the current message exchange step (additional queuing is not necessary).
*
* @param ctx the context from the handler where the frame was read.
* @param streamId the stream the frame was sent on.
* @param promisedStreamId the ID of the promised stream.
* @param headers the received headers.
* @param padding additional bytes that should be added to obscure the true content size. Must be between 0 and
* 256 (inclusive).
*/
void onPushPromiseRead(ChannelHandlerContext ctx, int streamId, int promisedStreamId,
Http2Headers headers, int padding) throws Http2Exception;
/**
* Handles an inbound {@code GO_AWAY} frame.
*
* @param ctx the context from the handler where the frame was read.
* @param lastStreamId the last known stream of the remote endpoint.
* @param errorCode the error code, if abnormal closure.
* @param debugData application-defined debug data. If this buffer needs to be retained by the
* listener they must make a copy.
*/
void onGoAwayRead(ChannelHandlerContext ctx, int lastStreamId, long errorCode, ByteBuf debugData)
throws Http2Exception;
/**
* Handles an inbound {@code WINDOW_UPDATE} frame.
*
* @param ctx the context from the handler where the frame was read.
* @param streamId the stream the frame was sent on.
* @param windowSizeIncrement the increased number of bytes of the remote endpoint's flow
* control window.
*/
void onWindowUpdateRead(ChannelHandlerContext ctx, int streamId, int windowSizeIncrement)
throws Http2Exception;
/**
* Handler for a frame not defined by the HTTP/2 spec.
*
* @param ctx the context from the handler where the frame was read.
* @param frameType the frame type from the HTTP/2 header.
* @param streamId the stream the frame was sent on.
* @param flags the flags in the frame header.
* @param payload the payload of the frame.
*/
void onUnknownFrame(ChannelHandlerContext ctx, byte frameType, int streamId, Http2Flags flags, ByteBuf payload)
throws Http2Exception;
}