fix(api): cache GitHub release assets

Cache GitHub release fetches locally and keep the release route dynamic.

Author: techwithanirudh

apps/api/nitro.config.ts

@@ -36,12 +36,6 @@ export default defineConfig({
     },
   },
   routeRules: {
-    "/release/**": {
-      headers: {
-        "cache-control":
-          "public, max-age=60, s-maxage=300, stale-while-revalidate=3600",
-      },
-    },
     "/main.user.css": {
       redirect: "/release/latest/?asset=main.user.css",
     },

apps/api/src/routes/release/[tag]/index.ts

@@ -90,16 +90,10 @@ export default defineHandler(async (event) => {
     if (import.meta.dev) {
       event.res.headers.set("X-Source", "local");
     } else {
-      event.res.headers.set(
-        "Cache-Control",
-        tag === "latest"
-          ? "public, max-age=60, s-maxage=300, stale-while-revalidate=3600"
-          : "public, max-age=31536000, immutable",
-      );
       event.res.headers.set("X-Source", "github");
       event.res.headers.set("X-Proxy-Host", "github.com");
       for (const name of allowedHeaders) {
-        const value = headers?.get(name);
+        const value = headers?.[name];
         if (value) event.res.headers.set(name, value);
       }
     }

apps/api/src/utils/fetcher.ts

@@ -1,5 +1,6 @@
 import { readFile } from "node:fs/promises";
 import { isAbsolute, resolve } from "node:path";
+import { defineCachedFunction } from "nitro/cache";
 import { HTTPError } from "nitro/h3";
 import { useRuntimeConfig } from "nitro/runtime-config";
 import { $fetch } from "ofetch";
@@ -12,7 +13,7 @@ const RETRYABLE_STATUS_CODES = new Set([408, 425, 429, 500, 502, 503, 504]);
 
 export interface FetchResult {
   content: string;
-  headers?: Headers;
+  headers?: Record<string, string>;
 }
 
 export async function fetchAsset(
@@ -22,9 +23,16 @@ export async function fetchAsset(
   if (import.meta.dev) {
     return fetchFromLocal(asset);
   }
-  return fetchFromGitHub(tag, asset);
+  return cachedFetchFromGitHub(tag, asset);
 }
 
+const cachedFetchFromGitHub = defineCachedFunction(fetchFromGitHub, {
+  name: "github-release-asset",
+  maxAge: 60,
+  staleMaxAge: 300,
+  getKey: (tag: string, asset: string) => `${tag}:${asset}`,
+});
+
 async function fetchFromGitHub(
   tag: string,
   asset: string,
@@ -46,7 +54,7 @@ async function fetchFromGitHub(
 
   return {
     content: typeof response._data === "string" ? response._data : "",
-    headers: new Headers(response.headers),
+    headers: Object.fromEntries(response.headers),
   };
 }