/*
* 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.example.stomp;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.stomp.DefaultStompFrame;
import io.netty.handler.codec.stomp.StompCommand;
import io.netty.handler.codec.stomp.StompFrame;
import io.netty.handler.codec.stomp.StompHeaders;
/**
* STOMP client inbound handler implementation, which just passes received messages to listener
*/
public class StompClientHandler extends SimpleChannelInboundHandler<StompFrame> {
private enum ClientState {
AUTHENTICATING,
AUTHENTICATED,
SUBSCRIBED,
DISCONNECTING
}
private ClientState state;
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
state = ClientState.AUTHENTICATING;
StompFrame connFrame = new DefaultStompFrame(StompCommand.CONNECT);
connFrame.headers().set(StompHeaders.ACCEPT_VERSION, "1.2");
connFrame.headers().set(StompHeaders.HOST, StompClient.HOST);
connFrame.headers().set(StompHeaders.LOGIN, StompClient.LOGIN);
connFrame.headers().set(StompHeaders.PASSCODE, StompClient.PASSCODE);
ctx.writeAndFlush(connFrame);
}
@Override
protected void messageReceived(ChannelHandlerContext ctx, StompFrame frame) throws Exception {
String subscrReceiptId = "001";
String disconReceiptId = "002";
switch (frame.command()) {
case CONNECTED:
StompFrame subscribeFrame = new DefaultStompFrame(StompCommand.SUBSCRIBE);
subscribeFrame.headers().set(StompHeaders.DESTINATION, StompClient.TOPIC);
subscribeFrame.headers().set(StompHeaders.RECEIPT, subscrReceiptId);
subscribeFrame.headers().set(StompHeaders.ID, "1");
System.out.println("connected, sending subscribe frame: " + subscribeFrame);
state = ClientState.AUTHENTICATED;
ctx.writeAndFlush(subscribeFrame);
break;
case RECEIPT:
String receiptHeader = frame.headers().get(StompHeaders.RECEIPT_ID);
if (state == ClientState.AUTHENTICATED && receiptHeader.equals(subscrReceiptId)) {
StompFrame msgFrame = new DefaultStompFrame(StompCommand.SEND);
msgFrame.headers().set(StompHeaders.DESTINATION, StompClient.TOPIC);
msgFrame.content().writeBytes("some payload".getBytes());
System.out.println("subscribed, sending message frame: " + msgFrame);
state = ClientState.SUBSCRIBED;
ctx.writeAndFlush(msgFrame);
} else if (state == ClientState.DISCONNECTING && receiptHeader.equals(disconReceiptId)) {
System.out.println("disconnected");
ctx.close();
} else {
throw new IllegalStateException("received: " + frame + ", while internal state is " + state);
}
break;
case MESSAGE:
if (state == ClientState.SUBSCRIBED) {
System.out.println("received frame: " + frame);
StompFrame disconnFrame = new DefaultStompFrame(StompCommand.DISCONNECT);
disconnFrame.headers().set(StompHeaders.RECEIPT, disconReceiptId);
System.out.println("sending disconnect frame: " + disconnFrame);
state = ClientState.DISCONNECTING;
ctx.writeAndFlush(disconnFrame);
}
break;
default:
break;
}
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
}