content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF 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 org.apache.activemq.transport.netty;
  
  import java.io.IOException;
  import java.net.URI;
  import java.nio.charset.StandardCharsets;
  
  import io.netty.channel.ChannelFuture;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import java.lang.invoke.MethodHandles;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.channel.Channel;
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.channel.ChannelInboundHandlerAdapter;
  import io.netty.channel.ChannelPipeline;
  import io.netty.handler.codec.http.DefaultHttpHeaders;
  import io.netty.handler.codec.http.FullHttpResponse;
  import io.netty.handler.codec.http.HttpClientCodec;
  import io.netty.handler.codec.http.HttpObjectAggregator;
  import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
  import io.netty.handler.codec.http.websocketx.CloseWebSocketFrame;
  import io.netty.handler.codec.http.websocketx.ContinuationWebSocketFrame;
  import io.netty.handler.codec.http.websocketx.PingWebSocketFrame;
  import io.netty.handler.codec.http.websocketx.PongWebSocketFrame;
  import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
  import io.netty.handler.codec.http.websocketx.WebSocketClientHandshaker;
  import io.netty.handler.codec.http.websocketx.WebSocketClientHandshakerFactory;
  import io.netty.handler.codec.http.websocketx.WebSocketFrame;
  import io.netty.handler.codec.http.websocketx.WebSocketVersion;
  
  /**
   * Transport for communicating over WebSockets
   */
  public class NettyWSTransport extends NettyTcpTransport {
  
     private static final Logger logger = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
  
     public static final String AMQP_SUB_PROTOCOL = "amqp";
  
     /**
      * Create a new transport instance
      *
      * @param remoteLocation the URI that defines the remote resource to connect to.
      * @param options        the transport options used to configure the socket connection.
      */
     public NettyWSTransport(URI remoteLocation, NettyTransportOptions options) {
        this(null, remoteLocation, options);
     }
  
     /**
      * Create a new transport instance
      *
      * @param listener       the TransportListener that will receive events from this Transport.
      * @param remoteLocation the URI that defines the remote resource to connect to.
      * @param options        the transport options used to configure the socket connection.
      */
     public NettyWSTransport(NettyTransportListener listener, URI remoteLocation, NettyTransportOptions options) {
        super(listener, remoteLocation, options);
     }
  
     @Override
     public void sendVoidPromise(ByteBuf output) throws IOException {
        writeAndFlush(output, channel.voidPromise(), BinaryWebSocketFrame::new);
     }
  
     @Override
     public ChannelFuture send(ByteBuf output) throws IOException {
        return writeAndFlush(output, channel.newPromise(), BinaryWebSocketFrame::new);
     }
  
     @Override
     protected ChannelInboundHandlerAdapter createChannelHandler() {
        return new NettyWebSocketTransportHandler();
     }
  
     @Override
     protected void addAdditionalHandlers(ChannelPipeline pipeline) {
        pipeline.addLast(new HttpClientCodec());
        pipeline.addLast(new HttpObjectAggregator(8192));
     }
  
     @Override
     protected void handleConnected(Channel channel) throws Exception {
        logger.trace("Channel has become active, awaiting WebSocket handshake! Channel is {}", channel);
     }
  
     // ----- Handle connection events -----------------------------------------//
  
     private class NettyWebSocketTransportHandler extends NettyDefaultHandler<Object> {
  
        private final WebSocketClientHandshaker handshaker;
  
        NettyWebSocketTransportHandler() {
           handshaker = WebSocketClientHandshakerFactory.newHandshaker(
              getRemoteLocation(), WebSocketVersion.V13, options.getWsSubProtocol(),
              true, new DefaultHttpHeaders(), getMaxFrameSize());
        }
  
        @Override
        public void channelActive(ChannelHandlerContext context) throws Exception {
           handshaker.handshake(context.channel());
  
           super.channelActive(context);
        }
  
        @Override
        protected void channelRead0(ChannelHandlerContext ctx, Object message) throws Exception {
           logger.trace("New data read: incoming: {}", message);
  
           Channel ch = ctx.channel();
           if (!handshaker.isHandshakeComplete()) {
              handshaker.finishHandshake(ch, (FullHttpResponse) message);
              logger.trace("WebSocket Client connected! {}", ctx.channel());
              // Now trigger super processing as we are really connected.
              NettyWSTransport.super.handleConnected(ch);
              return;
           }
  
           // We shouldn't get this since we handle the handshake previously.
           if (message instanceof FullHttpResponse response) {
              throw new IllegalStateException(
                 "Unexpected FullHttpResponse (getStatus=" + response.status() + ", content=" + response.content().toString(StandardCharsets.UTF_8) + ')');
           }
  
           WebSocketFrame frame = (WebSocketFrame) message;
           if (frame instanceof TextWebSocketFrame textFrame) {
              logger.warn("WebSocket Client received message: {}", textFrame.text());
              ctx.fireExceptionCaught(new IOException("Received invalid frame over WebSocket."));
           } else if (frame instanceof BinaryWebSocketFrame binaryFrame) {
              logger.trace("WebSocket Client received data: {} bytes", binaryFrame.content().readableBytes());
              listener.onData(binaryFrame.content());
           } else if (frame instanceof ContinuationWebSocketFrame continuationFrame) {
              logger.trace("WebSocket Client received data continuation: {} bytes", continuationFrame.content().readableBytes());
              listener.onData(continuationFrame.content());
           } else if (frame instanceof PingWebSocketFrame) {
              logger.trace("WebSocket Client received ping, response with pong");
              ch.write(new PongWebSocketFrame(frame.content()));
           } else if (frame instanceof CloseWebSocketFrame) {
              logger.trace("WebSocket Client received closing");
              ch.close();
           }
        }
     }
  }
  