Theo's Typesafe Cult•2mo ago

Running getServerSideProps auth checks from external function call

export const getServerSideProps: GetServerSideProps = async (ctx) => {
  const session = await getServerAuthSession(ctx);

  if (!session?.user.<AUTH_CHECK>) {
    return {
      redirect: {
        destination: "/",
        permanent: false,
      },
      props: {},
    };
  }

export const getServerSideProps: GetServerSideProps = async (ctx) => {
  const session = await getServerAuthSession(ctx);

  if (!session?.user.<AUTH_CHECK>) {
    return {
      redirect: {
        destination: "/",
        permanent: false,
      },
      props: {},
    };
  }

Hello there, I have frequent auth checks in my t3 (pages router), Depending on certain permissions or data, the user will be redirected to other pages. This is the case for multiple pages. I just want to clarify if offloading the processing on an external function call (to make these function calls callable in other pages more organized and reusable, as well as to declutter the long and repetitive getServerSideProps) is recommended or are there certain security risks from offloading the function calls externally? I assume the auth checks would still be done server-side (i plan on putting them somewhere like ~/server/helpers/auth.ts)

6 Replies

reddieOP•2mo ago

I am currently using this approach, i think it's a good way around it?

not sure how to properly type it though, the below works though

// ~/server/helpers/auth-helper.ts
import { type GetServerSidePropsResult } from "next";

export const returnToHome = {
  redirect: {
    destination: "/",
    permanent: false,
  },
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
} as GetServerSidePropsResult<Record<string, any>>;

// ~/server/helpers/auth-helper.ts
import { type GetServerSidePropsResult } from "next";

export const returnToHome = {
  redirect: {
    destination: "/",
    permanent: false,
  },
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
} as GetServerSidePropsResult<Record<string, any>>;

// ~/pages/page.tsx
  if (authCheck) {
    return returnToHome;
  }

// ~/pages/page.tsx
  if (authCheck) {
    return returnToHome;
  }

Neto•2mo ago

you could handle it at the edge (middleware) if you are doing light checks using GetServerSideProps should work but it's slower for light checks

reddieOP•2mo ago

Unfortunately, I am self-hosting this app via docker, so edge is not available

Neto•2mo ago

oh buddy.... middleware runs on the edge runtime either way lmao if you aren't doing any server side loading you can just export it like that

reddieOP•2mo ago

really? was not aware of that, mb mb.. i thought it was vercel-specific

Neto•2mo ago

welcome to nextjs 🙂

// src/lib/checker.ts
export function checker<T>(ctx: NextRequest): GetServerSidePropsResult<T> {
  ....
}

// src/pages/page.tsx

export const getServerSideProps = checker

// src/lib/checker.ts
export function checker<T>(ctx: NextRequest): GetServerSidePropsResult<T> {
  ....
}

// src/pages/page.tsx

export const getServerSideProps = checker

something like this?

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Running getServerSideProps auth checks from external function call