Add cache-control headers to attachments.redirect response

server/models/Attachment.ts

@@ -108,7 +108,7 @@ class Attachment extends IdModel {
   }
 
   /**
-   * Get a signed URL with the default expirt to download the attachment from storage.
+   * Get a signed URL with the default expiry to download the attachment from storage.
    */
   get signedUrl() {
     return FileStorage.getSignedUrl(this.key);

server/routes/api/attachments/attachments.ts

@@ -13,6 +13,7 @@ import AttachmentHelper from "@server/models/helpers/AttachmentHelper";
 import { authorize } from "@server/policies";
 import { presentAttachment } from "@server/presenters";
 import FileStorage from "@server/storage/files";
+import BaseStorage from "@server/storage/files/BaseStorage";
 import { APIContext } from "@server/types";
 import { RateLimiterStrategy } from "@server/utils/RateLimiter";
 import { assertIn } from "@server/validation";
@@ -171,8 +172,13 @@ const handleAttachmentsRedirect = async (
   });
 
   if (attachment.isPrivate) {
+    ctx.set(
+      "Cache-Control",
+      `max-age=${BaseStorage.defaultSignedUrlExpires}, immutable`
+    );
     ctx.redirect(await attachment.signedUrl);
   } else {
+    ctx.set("Cache-Control", `max-age=604800, immutable`);
     ctx.redirect(attachment.canonicalUrl);
   }
 };