HelloWorldHttp2Handler.java Source code

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Here is the source code for HelloWorldHttp2Handler.java

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/*
 * 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.
 */

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.http.HttpServerUpgradeHandler;
import io.netty.handler.codec.http2.AbstractHttp2ConnectionHandler;
import io.netty.handler.codec.http2.DefaultHttp2Connection;
import io.netty.handler.codec.http2.DefaultHttp2FrameReader;
import io.netty.handler.codec.http2.DefaultHttp2FrameWriter;
import io.netty.handler.codec.http2.DefaultHttp2Headers;
import io.netty.handler.codec.http2.DefaultHttp2InboundFlowController;
import io.netty.handler.codec.http2.DefaultHttp2OutboundFlowController;
import io.netty.handler.codec.http2.Http2Connection;
import io.netty.handler.codec.http2.Http2Exception;
import io.netty.handler.codec.http2.Http2FrameLogger;
import io.netty.handler.codec.http2.Http2Headers;
import io.netty.util.CharsetUtil;
import io.netty.util.internal.logging.InternalLoggerFactory;

import static io.netty.buffer.Unpooled.copiedBuffer;
import static io.netty.buffer.Unpooled.unreleasableBuffer;
import static io.netty.util.internal.logging.InternalLogLevel.INFO;

/**
 * A simple handler that responds with the message "Hello World!".
 */
public class HelloWorldHttp2Handler extends AbstractHttp2ConnectionHandler {

    private static final Http2FrameLogger logger = new Http2FrameLogger(INFO,
            InternalLoggerFactory.getInstance(Http2ClientConnectionHandler.class));
    static final ByteBuf RESPONSE_BYTES = unreleasableBuffer(copiedBuffer("Hello World", CharsetUtil.UTF_8));

    public HelloWorldHttp2Handler() {
        this(new DefaultHttp2Connection(true));
    }

    private HelloWorldHttp2Handler(Http2Connection connection) {
        super(connection, new DefaultHttp2FrameReader(), new DefaultHttp2FrameWriter(),
                new DefaultHttp2InboundFlowController(connection),
                new DefaultHttp2OutboundFlowController(connection));
    }

    /**
     * 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 HttpServerUpgradeHandler.UpgradeEvent) {
            // Write an HTTP/2 response to the upgrade request
            Http2Headers headers = DefaultHttp2Headers.newBuilder()
                    .set(Http2ExampleUtil.UPGRADE_RESPONSE_HEADER, "true").build();
            writeHeaders(ctx, ctx.newPromise(), 1, headers, 0, true, true);
        }
        super.userEventTriggered(ctx, evt);
    }

    /**
     * If receive a frame with end-of-stream set, send a pre-canned response.
     */
    @Override
    public void onDataRead(ChannelHandlerContext ctx, int streamId, ByteBuf data, int padding, boolean endOfStream,
            boolean endOfSegment) throws Http2Exception {
        if (endOfStream) {
            sendResponse(ctx(), streamId, data.retain());
        }
    }

    /**
     * If receive a frame with end-of-stream set, send a pre-canned response.
     */
    @Override
    public void onHeadersRead(ChannelHandlerContext ctx, int streamId, Http2Headers headers, int streamDependency,
            short weight, boolean exclusive, int padding, boolean endStream, boolean endSegment)
            throws Http2Exception {
        if (endStream) {
            sendResponse(ctx(), streamId, RESPONSE_BYTES.duplicate());
        }
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        cause.printStackTrace();
        ctx.close();
    }

    /**
     * Sends a "Hello World" DATA frame to the client.
     */
    private void sendResponse(ChannelHandlerContext ctx, int streamId, ByteBuf payload) {
        // Send a frame for the response status
        Http2Headers headers = DefaultHttp2Headers.newBuilder().status("200").build();
        writeHeaders(ctx(), ctx().newPromise(), streamId, headers, 0, false, false);

        writeData(ctx(), ctx().newPromise(), streamId, payload, 0, true, true);
    }
}