Cached Middleware Fetch Demo

How it works:

• The middleware fetches from an API endpoint that has a 1000ms delay
• Uses SWR (Stale-While-Revalidate) caching strategy with separate revalidate and expiry times
• Cache HIT: Fresh cached data served instantly (~0-5ms)
• Cache STALE: Cached data served instantly, background refresh triggered via waitUntil() (~0-5ms)
• Cache MISS: No cached data available, full API delay incurred (~1000ms)
• Data is fresh for 5 seconds (revalidate time)
• After 5 seconds, data becomes stale but is served instantly while refreshing in background
• After 30 seconds, cache expires completely and requires a fresh fetch
• The random value helps verify when the cache is actually being used
• Cache status provided via response headers: X-Cache-Status, X-Cache-Age, X-Cache-Expires-In