nextjs-template/proxy.ts

import { NextResponse, type NextRequest } from "next/server";
import { getSessionCookie } from "better-auth/cookies";

const PROTECTED_PATHS = ["/protected"];

export function proxy(request: NextRequest) {
  const { pathname } = request.nextUrl;

  if (PROTECTED_PATHS.some((p) => pathname.startsWith(p))) {
    const sessionCookie = getSessionCookie(request);
    if (!sessionCookie) {
      const loginUrl = new URL("/", request.url);
      loginUrl.searchParams.set("next", pathname);
      return NextResponse.redirect(loginUrl);
    }
  }

  return NextResponse.next();
}

export const config = {
  matcher: ["/((?!_next/static|_next/image|favicon.ico|api|.*\\..*).*)"],
};