How do I implement cache invalidation in my application?

How do I implement cache invalidation in my application?

Cache invalidation is crucial for ensuring that your application serves up-to-date data. There are several strategies you can use, such as time-based expiration, event-based invalidation, or manual invalidation. Which approach are you considering?

I'm thinking about using time-based expiration. How does that work?

Time-based expiration involves setting a specific time duration after which the cached data is considered stale. For example, you might cache a response for 10 minutes. After that period, the next request will fetch fresh data and update the cache. Would you like to know how to implement this in code?

Yes, please! Can you provide a code example?

Sure! If you're using a framework like Express.js, you can use middleware to handle caching. Here's a simple example using Node.js:

const cache = {};
const CACHE_DURATION = 10 * 60 * 1000; // 10 minutes

app.get('/data', (req, res) => {
    const now = Date.now();
    if (cache.data && (now - cache.timestamp < CACHE_DURATION)) {
        return res.json(cache.data);
    }
    // Fetch fresh data
    const freshData = fetchDataFromSource();
    cache.data = freshData;
    cache.timestamp = now;
    res.json(freshData);
});

This code checks if the cached data is still valid before serving it.

That makes sense! What about event-based invalidation?

Event-based invalidation involves updating or invalidating the cache in response to specific events, like data changes. For instance, if a user updates their profile, you would invalidate the cached profile data for that user. This ensures that users always see the most current information. Would you like to explore this further?