up

Author: pi0

src/presets/vercel/immutable.ts

@@ -1,7 +1,5 @@
-import { createHash } from "node:crypto";
-import fsp from "node:fs/promises";
 import { glob } from "tinyglobby";
-import { dirname, join, resolve } from "pathe";
+import { join, resolve } from "pathe";
 import { joinURL } from "ufo";
 import type { Nitro } from "nitro/types";
 import { isDirectory, writeFile } from "../_utils/fs.ts";
@@ -15,11 +13,9 @@ import { isDirectory, writeFile } from "../_utils/fs.ts";
 // overwrite an existing file with different content, so the file names embed a
 // content hash.
 //
-// They are served from the reserved `/_vercel/immutable/` path, so we relocate
-// the client build output out of the public `static/` dir into the top-level
-// `.vercel/output/_vercel/immutable/` dir and emit a
-// `.vercel/output/immutable.json` manifest mapping each file to a content hash
-// (derived from its content-addressed file name).
+// The client build emits them under the reserved `_vercel/immutable/` base of
+// the public `static/` output. Alongside them we emit a
+// `.vercel/output/immutable.json` manifest listing each immutable file.
 
 const IMMUTABLE_MANIFEST = "immutable.json";
 
@@ -40,22 +36,21 @@ export async function generateImmutableManifest(nitro: Nitro) {
   }
 
   // The client build emits content-addressed assets under the reserved
-  // `_vercel/immutable/` base inside the public `static/` output. Relocate them
-  // to the top-level `.vercel/output/_vercel/immutable/` dir (a sibling of
-  // `static/`), from where Vercel serves them at the absolute
-  // `/_vercel/immutable/` path, independent of the site `baseURL`.
-  const srcDir = join(nitro.options.output.publicDir, IMMUTABLE_DIR);
-  if (!(await isDirectory(srcDir))) {
+  // `_vercel/immutable/` base of the public `static/` output.
+  const immutableDir = join(nitro.options.output.publicDir, IMMUTABLE_DIR);
+  if (!(await isDirectory(immutableDir))) {
     return;
   }
-  const destDir = resolve(nitro.options.output.dir, IMMUTABLE_DIR);
-  await fsp.mkdir(dirname(destDir), { recursive: true });
-  await fsp.rename(srcDir, destDir);
 
-  const files = await glob("**", { cwd: destDir, absolute: false, dot: true });
+  const files = await glob("**", { cwd: immutableDir, absolute: false, dot: true });
+
+  // The file names already embed a long, content-addressed hash, so it is valid
+  // (per Vercel's Build Output API) to leave the manifest value empty and rely on
+  // the entropy in the file name. `VERCEL_HASH_SALT` is not used: Vite generates
+  // the file name hashes and they cannot be salted.
   const hashes: Record<string, string> = {};
   for (const file of files) {
-    hashes[joinURL("/", IMMUTABLE_DIR, file)] = ""
+    hashes[joinURL(nitro.options.baseURL, IMMUTABLE_DIR, file)] = "";
   }
 
   const manifest: ImmutableManifest = { version: 1, hashes };
@@ -66,4 +61,3 @@ export async function generateImmutableManifest(nitro: Nitro) {
 
   nitro.logger.withTag("vercel").info(`Generated immutable manifest (${files.length} files).`);
 }
-