tutorial.md

First, let's start with the App.js file.

This component uses the RxStomp library to interact with a RabbitMQ message broker via the STOMP protocol. It also uses React hooks such as useEffect and useState to handle the connection and the state of whether the user has joined the chatroom or not.

To start, you will need to install the @stomp/rx-stomp package by running npm install @stomp/rx-stomp in your project's root directory.

Next, import the RxStomp class from the @stomp/rx-stomp package at the top of your App.js file, like so:

import { RxStomp } from '@stomp/rx-stomp';

Create a new instance of the RxStomp class by creating a state variable named rxStomp and set it to a new instance of RxStomp.

const [rxStomp, setRxStomp] = useState(new RxStomp());

Use the useEffect hook to configure the connection to the message broker. In the useEffect callback, you can set the configuration options for the connection, such as the broker URL, login credentials, and heartbeat settings.

useEffect(() => {
    const rxStompConfig = {
      brokerURL: 'ws://localhost:15674/ws',
      connectHeaders: {
        login: 'guest',
        passcode: 'guest'
      },
      debug: (msg) => {
        console.log(new Date(), msg);
      },
      heartbeatIncoming: 0,
      heartbeatOutgoing: 20000,
      reconnectDelay: 200
    };

    rxStomp.configure(rxStompConfig);
    rxStomp.activate();

    return () => {
      rxStomp.deactivate();
    };
  }, []);

Next, create a state variable named joinedChatroom and set it to false using the useState hook.

const [joinedChatroom, setJoinedChatroom] = useState(false);

In the JSX of the component, use the Status component to display the current connection status, and Chatroom component to display the chatroom once the user joins it.

<Status rxStomp={rxStomp} />

{!joinedChatroom && <button onClick={() => setJoinedChatroom(true)}>Join chatroom!</button>}
{joinedChatroom && <button onClick={() => setJoinedChatroom(false)}>Leave chatroom!</button>}

{joinedChatroom && <Chatroom rxStomp={rxStomp} />}

Now that you've created the App.js component, let's move on to the Chatroom.js component.

This component displays a chatroom UI, where the user can enter a username and a message and send it to the message broker.

To start, create a state variable named message and set it to an empty string using the useState hook.

const [message, setMessage] = useState('');

Next, create a state variable named chatMessages and set it to an empty array using the useState hook. This will be used to store the messages received from the message broker.

const [chatMessages, setChatMessages] = useState([]);

Create a state variable named userName and set it to a random username using the useState hook.

const [userName, setUserName] = useState(`user${Math.floor(Math.random() * 1000)}`);

Use the useEffect hook to subscribe to a topic on the message broker. In this case, the topic is /topic/test. In the subscription callback, parse the message body and add it to the chatMessages state variable.

useEffect(() => {
    const subscription = props.rxStomp.watch('/topic/test').subscribe((message) => {
      const messageBody = JSON.parse(message.body);
      setChatMessages(chatMessages => [...chatMessages, messageBody]);
    });

    return () => {
      subscription.unsubscribe();
    };
  }, []);

Create a function named sendMessage that is called when the user clicks the "Send Message" button. In this function, use the rxStomp.publish method to send the message to the /topic/test topic on the message broker.

function sendMessage () {
    const body = JSON.stringify({ user: userName, message });
    props.rxStomp.publish({ destination: '/topic/test', body });
    setMessage('');
  }

Finally, in the JSX of the component, render a form for the user to enter their username and message, and a button to send the message. Also, render a list of the received messages.

<>
  <h2>Chatroom</h2>

  <label htmlFor="username">Username: </label>
  <input type="text" name="username" value={userName} onChange={(e) => setUserName(e.target.value)} />

  <label htmlFor="message">Message: </label>

  <input type="text" value={message} onChange={(e) => setMessage(e.target.value)} name="message"/>
  <button onClick={() => sendMessage()}>Send Message</button>

  <p><strong>Chat Messages</strong></p>
  <ul>
    {chatMessages.map((chatMessage, index) => (
      <li key={index}>
        <strong>{chatMessage.user}</strong>: {chatMessage.message}
      </li>
    ))}
  </ul>
</>

Finally, the Status.js component is using the useEffect hook to subscribe to the connectionState$ observable provided by the RxStomplibrary to update the connectionStatus state variable with the current connection status.

To start, import the RxStompState enumeration from the @stomp/rx-stomp package at the top of your Status.js file.

import { RxStompState } from '@stomp/rx-stomp';

Next, create a state variable named connectionStatus and set it to null using the useState hook.

const [connectionStatus, setConnectionStatus] = useState(null);

Use the useEffect hook to subscribe to the connectionState$ observable provided by the rxStomp instance passed down as a prop. In the subscription callback, use the RxStompState enumeration to map the connection state to a human-readable string and update the connectionStatus state variable.

useEffect(() => {
    const subscriptionOb = props.rxStomp.connectionState$.subscribe((state) => {
      setConnectionStatus(RxStompState[state]);
    });

    return () => {
      subscriptionOb.unsubscribe();
    };
  }, []);

Finally, in the JSX of the component, render the current connection status.

<div>
    <h2>Connection Status: {connectionStatus} </h2>
</div>

By following these steps, you should be able to recreate these components and connect to a RabbitMQ message broker using the STOMP protocol, and interact with it via the RxStomp library. Please let me know if you have any questions along the way or if there is something else I can help you with. Can you add a post of an addendum on how to use that docker script to set up the rabbitmq broker. Some people might not have one running at the moment.

Sure, to use the Dockerfile provided in your previous message to set up a RabbitMQ broker, you will need to have Docker installed on your machine.

Start by creating a new directory on your machine where you want to store the Dockerfile.
Copy the content of the Dockerfile provided in your previous message to a file named Dockerfile in the directory you just created.
Open a terminal and navigate to the directory where you created the Dockerfile.
Run the command docker build -t rabbitmq-stomp . to build the Docker image. This command tells Docker to build an image using the Dockerfile in the current directory and to tag the image with the name rabbitmq-stomp.
Once the image is built, you can run the command docker run -p 15674:15674 rabbitmq-stomp to start a new container based on the image. This command tells Docker to start a new container using the rabbitmq-stomp image and to map port 15674 on the host to port 15674 in the container.
You can now access the RabbitMQ management interface by navigating to http://localhost:15674 in your web browser.

You should now have a RabbitMQ broker running in a Docker container and configured to use the STOMP protocol over WebSockets on port 15674. You can now proceed with the tutorial on how to use the React components to interact with the broker via the Stomp protocol. Please let me know if you have any further questions.