How do I check if a user is logged in on every request in Next.js?

Question

I need help with my Next.js project. I take the token in the cookie from the serverSideProps of each page and bring the profile information. The appearance of the profile information means that the user is logged in. I am using this code on every page. that didn't feel right. How will I check if the profile information exists in every query? And when is a protected route I need to redirect the user to the login page.

export async function getServerSideProps(context) {
  const token = await getToken(context);
  if (token) {
    const profile = await getProfile(token);
    if (profile) {
      return {
        props: {
          profile: profile.data.user,
          token,
        },
      };
    }
    //if user is not found redirect
    return {
      redirect: {
        destination: "/",
        permanent: false,
      },
    };
  }
  return {
    props: {},
  };
}

Answer 1

You can use middleware. in pages directory, create _middleware.js.

import { NextResponse } from "next/server";

// we are not exporting by default
export async function middleware(req, ev) {
  
  const token = req ? req.cookies?.token : null;
  const profile = await getProfile(token);
  // if profile exists you want to continue. Also
  // maybe user sends request for log-in, and if a user wants to login, obviously it has no token
  const { pathname } = req.nextUrl;
  if (
    // whatever your api route for login is
    pathname.includes("/api/login") || profile 
  ) {
    return NextResponse.next();
  }

  
  if (!profile && pathname !== "/login") {
    // since you want to redirect the user to "/"
    return NextResponse.redirect("/");
  }
}