VYBECODEDDDDDDDDD

src/routes/download.ts

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+import { lstat } from "node:fs/promises";
+import { notFound } from "../http";
+import { log } from "../log";
+import { contentDisposition, fileIdFromKey, KEY_PATTERN, secretMatches } from "../security";
+import type { Storage } from "../storage";
+
+export async function handleDownload(
+  req: Request,
+  storage: Storage,
+  rawKey: string,
+): Promise<Response> {
+  if (!KEY_PATTERN.test(rawKey)) return notFound();
+  const id = fileIdFromKey(rawKey);
+  if (!id) return notFound();
+
+  const meta = await storage.readMetadata(id);
+  if (!meta) return notFound();
+  if (!secretMatches(meta.downloadKeyHash, rawKey)) return notFound();
+
+  const filePath = storage.filePath(id);
+  let fileStat;
+  try {
+    fileStat = await lstat(filePath);
+  } catch {
+    return notFound();
+  }
+  if (!fileStat.isFile()) return notFound();
+
+  const headers = new Headers({
+    "content-type": meta.mimeType || "application/octet-stream",
+    "content-length": String(fileStat.size),
+    "content-disposition": contentDisposition(meta.originalName),
+    "cache-control": "private, no-store",
+    "x-content-type-options": "nosniff",
+    "referrer-policy": "no-referrer",
+  });
+
+  if (req.method === "HEAD") return new Response(null, { status: 200, headers });
+
+  log("info", `download id=${id} size=${fileStat.size}`);
+  return new Response(Bun.file(filePath).stream(), { status: 200, headers });
+}