How to handle a long asynchronous operation on the client side (virus scan, up to an hour)?

To handle a long asynchronous operation on the client side, such as virus scanning a file that may take up to an hour, you can use the following approach:

1. Send the file to the server — the client uploads the file and receives a unique task identifier.

2. Periodic status polling — the client sends a request to the server at a set interval (e.g., every 10-30 seconds) to check the scan status.

3. Display progress or status — show the user that the scan is in progress and update the status as responses are received.

4. Handle the result — when the server reports that the scan is complete, display the result (e.g., file is clean or infected).

Example in React using setInterval:

function VirusCheck({ taskId }) {
  const [status, setStatus] = React.useState('pending');

  React.useEffect(() => {
    const interval = setInterval(() => {
      fetch(`/api/check-status/${taskId}`)
        .then(res => res.json())
        .then(data => {
          setStatus(data.status);
          if (data.status === 'done' || data.status === 'error') {
            clearInterval(interval);
          }
        });
    }, 30000); // poll every 30 seconds

    return () => clearInterval(interval);
  }, [taskId]);

  return <div>Scan status: {status}</div>;
}

This approach allows the interface to remain responsive and informs the user about the progress of the long operation.