use cache via nuxt config

nuxt.config.ts

@@ -82,6 +82,13 @@ export default defineNuxtConfig({
       crawlLinks: false,
       routes: ['/', '/200.html'],
     },
+    routeRules: {
+      '/api/og-image': {
+        cache: {
+          maxAge: 86400, // 1 day
+        },
+      },
+    },
   },
   app: {
     keepalive: true,

server/api/og-image.ts

@@ -1,4 +1,9 @@
-const inMemoryCache = new Map<string, { url: string; lastUsed: number }>()
+// This API-Endpoint will be cached via nuxt.config.ts -> nitro.routeRules['/api/og-image'].cache.maxAge = 86400
+
+function extractOgImageUrl(html: string): string {
+  const match = html.match(/<meta property="og:image" content="([^"]+)" \/>/)
+  return match?.[1] ?? ''
+}
 
 export default defineEventHandler(async (event) => {
   const { cardUrl } = getQuery(event)
@@ -17,34 +22,9 @@ export default defineEventHandler(async (event) => {
     })
   }
 
-  if (inMemoryCache.has(cardUrl)) {
+  const html = await $fetch<string>(cardUrl)
-    const { url } = inMemoryCache.get(cardUrl)!
+  const ogImageUrl = extractOgImageUrl(html)
-    await send(event, url)
-
-    inMemoryCache.set(cardUrl, { url, lastUsed: Date.now() })
-
-    // Remove some oldest entries if cache gets to big
-    if (inMemoryCache.size > 5000) {
-      // Remove 10% of the oldest entries
-      const entries = Array.from(inMemoryCache.entries()).sort(
-        (a, b) => a[1].lastUsed - b[1].lastUsed,
-      )
-      const entriesToRemove = Math.floor(entries.length * 0.1)
-
-      for (let i = 0; i < entriesToRemove; i++)
-        inMemoryCache.delete(entries[i][0])
-    }
-
-    return
-  }
-
-  const result = await $fetch<string>(cardUrl)
-  let ogImageUrl: string | null | undefined = null
-
-  const match = result.match(/<meta property="og:image" content="([^"]+)" \/>/)
-  ogImageUrl = match?.[1] ?? ''
-
-  inMemoryCache.set(cardUrl, { url: ogImageUrl, lastUsed: Date.now() })
 
   await send(event, ogImageUrl)
 })
+