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How to test if my caching is working?

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American black bear posted this in #help-forum
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American black bearOP
How can I test if the functions are being cached correctly with the "use cache" directive? The docs say that by default functions cached with use cache, without specifying cacheLife last for 5 minutes, but when I change something in my CMS and refresh the page displaying the content new theme has been applied even though it should last those 5 minutes if I don't revalidate it. Is this expected or am I not caching my function output properly?

For example I have something like this:

export async function getTheme({
  isDraftMode = false,
  tenantDomain,
}: {
  isDraftMode?: boolean;
  tenantDomain: string | null;
}): Promise<ThemeType | null> {
  "use cache";

  cacheTag(
    settingsTag.global,
    settingsTag.tenant(tenantDomain),
    settingsTag.theme(tenantDomain),
  );

  try {
    const db = await dbClient()
    
    const result = // ... fetch logic

    return result ?? null
  } catch (error) {
    console.error(error);
    return null;
  }
}

13 Replies

American black bearOP
Yeah I was trying in the production
American black bearOP
This is how I am currently handling draft mode for preview. Could this be causing an issue with caching?

import { headers, draftMode as nextDraftMode } from "next/headers";

export const dynamic = "force-dynamic";

export default async function DynamicPage({
  params,
  searchParams,
}: {
  params: DynamicPageParams;
  searchParams: DynamicPageSearchParams;
}) {
  let page: Page | null = null;

  const { slug } = await params;
  const { draft } = await searchParams;

  const draftMode = await nextDraftMode();
  const tenantDomain = await getTenantDomain();

  try {
    let user: User | null = null;

    if (draft === "true") {
      const reqHeaders = await headers();
      user = await getUser(reqHeaders);
    }

    if (user?.id) {
      draftMode.enable();
    } else {
      draftMode.disable();
    }

    page = await getPageBySlug({
      slug,
      isDraftMode: draftMode.isEnabled,
      tenantDomain,
    });
  } catch (error) {
    console.error(error);
  }

  if (!page) {
    return notFound();
  }

  return (
    <>
      {draftMode.isEnabled && <RefreshRouteOnSave />}
      <main className="min-h-[calc(100vh-73px)]">
        {page.content?.map((content) => (
          <SectionRenderer key={content.id} content={content} />
        ))}
      </main>
    </>
  );
}
and keep in mind use cache is currently in canary, so there can be bugs
American black bearOP
// next.config.json

import { withPayload } from "@payloadcms/next/withPayload";

/**
 * Run `build` or `dev` with `SKIP_ENV_VALIDATION` to skip env validation. This is especially useful
 * for Docker builds.
 */
import "./src/env.js";
import { env } from "./src/env.js";

/** @type {import("next").NextConfig} */
const config = {
  experimental: {
    useCache: true,
  },
  images: {
    remotePatterns: [
      {
        hostname: "app",
        protocol: "http",
        port: "3000",
      },
      {
        hostname: "localhost",
        protocol: "http",
        port: "3000",
      },
      {
        hostname: env.NEXT_PUBLIC_DOMAIN,
        protocol: "https",
      },
    ],
  },
  async rewrites() {
    const rewrites = [];

    if (env.NEXT_PUBLIC_ENABLE_ANALYTICS === "true") {
      rewrites.push(
        {
          source: "/ingest/static/:path*",
          destination: `${env.NEXT_PUBLIC_POSTHOG_ASSETS_HOST}/static/:path*`,
        },
        {
          source: "/ingest/:path*",
          destination: `${env.NEXT_PUBLIC_POSTHOG_HOST}/:path*`,
        },
        {
          source: "/ingest/decide",
          destination: `${env.NEXT_PUBLIC_POSTHOG_HOST}/decide`,
        },
      );
    }

    return rewrites;
  },
  skipTrailingSlashRedirect: true,
  output: "standalone",
  transpilePackages: ["@t3-oss/env-nextjs", "@t3-oss/env-core"],
};

export default withPayload(config);
// package.json

dependencies: {
  // ...
  "next": "15.3.3",
}
American black bearOP
any ideas or tips on how I can debug this?
American black bearOP
Is that mandatory?
I think the docs say that default is 15min if no cacheLife is specified
@American black bear Is that mandatory?
Anay-208 | Ping in replies
It could be because you've created a cacheTag, and you haven't revalidated it anywhere so there is basically no cache