How to obtain user/session on getLocale

[SirBernardPhilip]

Hey! I see that you mention the option of using a "userId" to fetch a locale from the DB, but since we dont have the context Im unsure how the user or session could be obtained?

Is there a different approach Im missing?

[marcellosso]

@SirBernardPhilip Hey! Sorry for the super late reply, my bad 🙏

And thanks a lot for opening this issue, the confusion here is totally on me for not explaining the context properly. Let me clarify how getLocale is meant to work.

getLocale receives a regular Request object, the same one your framework/route handler receives. What that means is that you decide where the locale comes from, using whatever info you already have inside that request:

• cookies
• headers
• JWT / session token
• database (if you want)
• anything else your app uses

When I mentioned “getting locale from the DB using a userId”, I meant:
if your session cookie/JWT already contains a userId, you could decode it in getLocale and look up the locale in your DB. But that’s just one possible approach, not something the plugin requires.

A few examples:

A) Locale stored directly in a cookie (simplest)

getLocale: async (req) => {
  const cookieHeader = req.headers.get("cookie");
  const locale = parseCookie(cookieHeader).locale;
  return locale ?? "default";
};

B) From a header (e.g. mobile apps / proxies)

req.headers.get("x-user-locale") ?? "default";

C) Decode your session/JWT

If your auth flow stores user info inside a signed token:

const session = decodeSession(req.headers.get("cookie"));
return session?.user?.locale ?? "default";

D) Fetch from the DB using the userId

Only makes sense if your session contains a userId:

getLocale: async (req) => {
  const session = decodeSession(req.headers.get("cookie"));
  const userId = session?.userId;
  if (!userId) return "default";

  const userLocale = await db.user.getLocale(userId);
  return userLocale ?? "default";
};

I will be updating the README of the project to clarify on this, thanks a lot for bringing this up and again, sorry for the late reply.