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HelloWorldHttp2Handler.java
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/
HelloWorldHttp2Handler.java
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/*
* 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:
*
* 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.example.http2.helloworld.multiplex.server;
import static io.netty.buffer.Unpooled.copiedBuffer;
import static io.netty.buffer.Unpooled.unreleasableBuffer;
import static io.netty.handler.codec.http.HttpResponseStatus.OK;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufUtil;
import io.netty.channel.ChannelDuplexHandler;
import io.netty.channel.ChannelHandler.Sharable;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.http2.DefaultHttp2DataFrame;
import io.netty.handler.codec.http2.DefaultHttp2Headers;
import io.netty.handler.codec.http2.DefaultHttp2HeadersFrame;
import io.netty.handler.codec.http2.Http2DataFrame;
import io.netty.handler.codec.http2.Http2Headers;
import io.netty.handler.codec.http2.Http2HeadersFrame;
import io.netty.util.CharsetUtil;
/**
* A simple handler that responds with the message "Hello World!".
*
* <p>This example is making use of the "multiplexing" http2 API, where streams are mapped to child
* Channels. This API is very experimental and incomplete.
*/
@Sharable
public class HelloWorldHttp2Handler extends ChannelDuplexHandler {
static final ByteBuf RESPONSE_BYTES = unreleasableBuffer(
copiedBuffer("Hello World", CharsetUtil.UTF_8)).asReadOnly();
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
super.exceptionCaught(ctx, cause);
cause.printStackTrace();
ctx.close();
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
if (msg instanceof Http2HeadersFrame) {
onHeadersRead(ctx, (Http2HeadersFrame) msg);
} else if (msg instanceof Http2DataFrame) {
onDataRead(ctx, (Http2DataFrame) msg);
} else {
super.channelRead(ctx, msg);
}
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
ctx.flush();
}
/**
* If receive a frame with end-of-stream set, send a pre-canned response.
*/
private static void onDataRead(ChannelHandlerContext ctx, Http2DataFrame data) throws Exception {
if (data.isEndStream()) {
sendResponse(ctx, data.content());
} else {
// We do not send back the response to the remote-peer, so we need to release it.
data.release();
}
}
/**
* If receive a frame with end-of-stream set, send a pre-canned response.
*/
private static void onHeadersRead(ChannelHandlerContext ctx, Http2HeadersFrame headers)
throws Exception {
if (headers.isEndStream()) {
ByteBuf content = ctx.alloc().buffer();
content.writeBytes(RESPONSE_BYTES.duplicate());
ByteBufUtil.writeAscii(content, " - via HTTP/2");
sendResponse(ctx, content);
}
}
/**
* Sends a "Hello World" DATA frame to the client.
*/
private static void sendResponse(ChannelHandlerContext ctx, ByteBuf payload) {
// Send a frame for the response status
Http2Headers headers = new DefaultHttp2Headers().status(OK.codeAsText());
ctx.write(new DefaultHttp2HeadersFrame(headers));
ctx.write(new DefaultHttp2DataFrame(payload, true));
}
}