feat: initial implementation

Author: pieh

src/run/handlers/server.ts

@@ -25,6 +25,7 @@ import { setupWaitUntil } from './wait-until.cjs'
 setFetchBeforeNextPatchedIt(globalThis.fetch)
 // configure some globals that Next.js make use of before we start importing any Next.js code
 // as some globals are consumed at import time
+// TODO: only call this if Next.js version is using CacheHandlerV2 as we don't have V1 compatible implementation
 configureUseCacheHandlers()
 setupWaitUntil()
 

src/run/handlers/tags-handler.cts

@@ -25,6 +25,27 @@ async function lastTagRevalidationTimestamp(
   return tagManifest.revalidatedAt
 }
 
+/**
+ * Get the most recent revalidation timestamp for a list of tags
+ */
+export async function getMostRecentTagRevalidationTimestamp(tags: string[]) {
+  if (tags.length === 0) {
+    return 0
+  }
+
+  const cacheStore = getMemoizedKeyValueStoreBackedByRegionalBlobStore({ consistency: 'strong' })
+
+  const timestampsOrNulls = await Promise.all(
+    tags.map((tag) => lastTagRevalidationTimestamp(tag, cacheStore)),
+  )
+
+  const timestamps = timestampsOrNulls.filter((timestamp) => timestamp !== null)
+  if (timestamps.length === 0) {
+    return 0
+  }
+  return Math.max(...timestamps)
+}
+
 /**
  * Check if any of the tags were invalidated since the given timestamp
  */