using headers in getRequestConfig SSG not working

[bennajah]

when use this config and build app SSG not working

when remove headers code its working

import deepmerge from "deepmerge";
import { cookies, headers } from "next/headers";
import { type Formats, hasLocale } from "next-intl";
import { getRequestConfig } from "next-intl/server";
import { COOKIE_NAME, defaultLocale, locales } from "@/i18n/config";
import defaultMessages from "~/messages/en.json" with { type: "json" };

export default getRequestConfig(async ({ requestLocale }) => {
  let candidate = await requestLocale;
  if (!candidate) {
    const store = await cookies();
    candidate = store.get(COOKIE_NAME)?.value;
  }

  const locale = hasLocale(locales, candidate) ? candidate : defaultLocale;
  const now = (await headers()).get("x-now");
  const timeZone = (await headers()).get("x-time-zone") ?? "Europe/Vienna";
  const localeMessages = (await import(`~/messages/${locale}.json`)).default;
  const messages = deepmerge(defaultMessages, localeMessages);

  return {
    locale,
    now: now ? new Date(now) : new Date(),
    timeZone,
    messages,
    formats,
  };
});

[tclxshunquan-wang]

It seems that the relevant data from the cookie was used in the requestLocale function. However, when Next.js performed SSG compilation, it considered this to be illegal and thus did not generate the SSG output.

Running next build -d will allow you to see the detailed errors.

Does the current situation have any good solutions? @amannn

error message:

[amannn]

When using cookies still build app with ssg

I guess only if you don't end up in that branch. Calling cookies() definitely requires dynamic rendering.

As far as I know Next.js <16 sometimes reported pages incorrectly being rendered as static despite them using dynamic APIs, but if you're on the latest version you should see every route that uses cookies() also switching to dynamic rendering.

[FanetheDivine]

When using cookies still build app with ssg

I guess only if you don't end up in that branch. Calling cookies() definitely requires dynamic rendering.

As far as I know Next.js <16 sometimes reported pages incorrectly being rendered as static despite them using dynamic APIs, but if you're on the latest version you should see every route that uses cookies() also switching to dynamic rendering.

it helps.

But is the step3 Use the locale param in metadata necessary?after calling setRequestLocale(), the cache of locale is set, then the functions like getMessages will never call headers()

[amannn]

But is the step3 Use the locale param in metadata necessary?

Metadata also renders in parallel to a page. So you could either call setRequestLocale there as well, but just forwarding the locale is easier there from my experience.

Once we get rid of setRequestLocale you'll also not have to forward the locale in metadata.

[bennajah]

@amannn

I think should use
This
'use cache: private' for headers and cookies

See this --> https://nextjs.org/docs/app/api-reference/directives/use-cache-private

But is the step3 Use the locale param in metadata necessary?

Metadata also renders in parallel to a page. So you could either call setRequestLocale there as well, but just forwarding the locale is easier there from my experience.

Once we get rid of setRequestLocale you'll also not have to forward the locale in metadata.

[amannn]

'use cache: private' only caches user-specific data for the client side, for static rendering you want a shared cache on the server.