What is async middleware and how is it implemented in different programming languages?

What is async middleware and how is it used in Node.js?

Async middleware in Node.js allows you to handle asynchronous operations in your request-response cycle. It helps manage tasks like database calls or API requests without blocking the main thread.

Can you give me an example of async middleware in Express?

Sure! In Express, you can create async middleware like this:

app.use(async (req, res, next) => {
  try {
    const data = await fetchData();
    req.data = data;
    next();
  } catch (error) {
    next(error);
  }
});

How does async middleware differ in Python's Flask?

In Flask, you can use async functions directly as route handlers. Here's an example:

@app.route('/data')
async def get_data():
    data = await fetch_data()
    return jsonify(data)

What about async middleware in Ruby on Rails?

In Ruby on Rails, you can use ActionCable for async operations. Middleware can be implemented using background jobs with ActiveJob to handle tasks asynchronously.