initial commit

web/vue-app/src/common/imageCache.ts

@@ -0,0 +1,64 @@
+export const DEFAULT_IMAGE_CACHE = 'images-v1'
+
+const objectUrlMap = new Map<string, string>()
+
+export async function getCachedImageUrl(
+  imageId: string,
+  cacheName = DEFAULT_IMAGE_CACHE,
+): Promise<string> {
+  if (!imageId) throw new Error('imageId required')
+
+  // reuse existing object URL if created in this session
+  const existing = objectUrlMap.get(imageId)
+  if (existing) return existing
+
+  const requestUrl = `/api/image/request/${imageId}`
+
+  // Try Cache Storage first
+  let response: Response | undefined
+  if ('caches' in window) {
+    const cache = await caches.open(cacheName)
+    response = await cache.match(requestUrl)
+    if (!response) {
+      const fetched = await fetch(requestUrl)
+      if (!fetched.ok) throw new Error(`HTTP ${fetched.status}`)
+      // store a clone in Cache Storage (non-blocking)
+      cache.put(requestUrl, fetched.clone()).catch((e) => {
+        console.warn('Cache put failed:', e)
+      })
+      response = fetched
+    }
+  } else {
+    const fetched = await fetch(requestUrl)
+    if (!fetched.ok) throw new Error(`HTTP ${fetched.status}`)
+    response = fetched
+  }
+
+  const blob = await response.blob()
+  const objectUrl = URL.createObjectURL(blob)
+  objectUrlMap.set(imageId, objectUrl)
+  return objectUrl
+}
+
+export function revokeImageUrl(imageId: string) {
+  const url = objectUrlMap.get(imageId)
+  if (url) {
+    try {
+      URL.revokeObjectURL(url)
+    } catch (e) {
+      /* ignore */
+    }
+    objectUrlMap.delete(imageId)
+  }
+}
+
+export function revokeAllImageUrls() {
+  for (const url of objectUrlMap.values()) {
+    try {
+      URL.revokeObjectURL(url)
+    } catch (e) {
+      /* ignore */
+    }
+  }
+  objectUrlMap.clear()
+}