How can I use Server-Sent Events in my web application?

How can I use Server-Sent Events in my web application?

You can use Server-Sent Events (SSE) to push real-time updates from the server to the client. First, set up an endpoint on your server that sends events in the correct format.

What format should the events be in?

The events should be sent as text/event-stream. Each event should start with 'data:' followed by the message, and end with two newlines.

Can you give me a code example?

Sure! Here's a simple example:

// Server-side (Node.js)
app.get('/events', (req, res) => {
  res.setHeader('Content-Type', 'text/event-stream');
  res.setHeader('Cache-Control', 'no-cache');
  res.setHeader('Connection', 'keep-alive');

  setInterval(() => {
    res.write(`data: ${new Date().toISOString()}\n\n`);
  }, 1000);
});

How do I receive these events on the client side?

On the client side, you can use the EventSource API:

const eventSource = new EventSource('/events');

eventSource.onmessage = function(event) {
  console.log('New event:', event.data);
};