feat: static assets incremental cache

Author: james-elicx

packages/cloudflare/src/api/overrides/incremental-cache/static-assets-incremental-cache.ts

@@ -0,0 +1,53 @@
+import { debug, error } from "@opennextjs/aws/adapters/logger.js";
+import type { CacheValue, IncrementalCache, WithLastModified } from "@opennextjs/aws/types/overrides.js";
+import { IgnorableError } from "@opennextjs/aws/utils/error.js";
+
+import { getCloudflareContext } from "../../cloudflare-context.js";
+
+export const CACHE_DIR = "cdn-cgi/_next_cache";
+
+export const NAME = "cf-static-assets-incremental-cache";
+
+/**
+ * This cache uses KV static assets and is not recommended. It should only be used for applications
+ * that do NOT want revalidation and ONLY want to serve pre-rendered data.
+ */
+class StaticAssetsIncrementalCache implements IncrementalCache {
+  readonly name = NAME;
+
+  async get<IsFetch extends boolean = false>(
+    key: string,
+    isFetch?: IsFetch
+  ): Promise<WithLastModified<CacheValue<IsFetch>> | null> {
+    const assets = getCloudflareContext().env.ASSETS;
+    if (!assets) throw new IgnorableError("No Static Assets");
+
+    debug(`Get ${key}`);
+
+    try {
+      const response = await assets.fetch(this.getAssetUrl(key, isFetch));
+      if (!response.ok) return null;
+
+      return {
+        value: await response.json(),
+        // __BUILD_TIMESTAMP_MS__ is injected by ESBuild.
+        lastModified: (globalThis as { __BUILD_TIMESTAMP_MS__?: number }).__BUILD_TIMESTAMP_MS__,
+      };
+    } catch (e) {
+      error("Failed to get from cache", e);
+      return null;
+    }
+  }
+
+  async set(): Promise<void> {}
+
+  async delete(): Promise<void> {}
+
+  protected getAssetUrl(key: string, isFetch?: boolean): string {
+    const buildId = process.env.NEXT_BUILD_ID ?? "no-build-id";
+    const name = `${CACHE_DIR}/${buildId}/${key}.${isFetch ? "fetch" : "cache"}`.replace(/\/+/g, "/");
+    return `http://assets.local/${name}`;
+  }
+}
+
+export default new StaticAssetsIncrementalCache();