link-stack/apps/link/middleware.ts

import { NextResponse } from "next/server";
import { withAuth, NextRequestWithAuth } from "next-auth/middleware";
import { createLogger } from "@link-stack/logger";

const logger = createLogger('link-middleware');

const rewriteURL = (
  request: NextRequestWithAuth,
  originBaseURL: string,
  destinationBaseURL: string,
  headers: any = {},
) => {
  logger.debug({ 
    originBaseURL, 
    destinationBaseURL, 
    headerKeys: Object.keys(headers) 
  }, "Rewriting URL");
  let path = request.url.replace(originBaseURL, "");
  if (path.startsWith("/")) {
    path = path.slice(1);
  }
  const destinationURL = `${destinationBaseURL}/${path}`;
  logger.debug({ from: request.url, to: destinationURL }, "URL rewrite");
  const requestHeaders = new Headers(request.headers);

  requestHeaders.delete("x-forwarded-user");
  requestHeaders.delete("x-forwarded-roles");
  requestHeaders.delete("connection");

  for (const [key, value] of Object.entries(headers)) {
    requestHeaders.set(key, value as string);
  }

  return NextResponse.rewrite(new URL(destinationURL), {
    request: { headers: requestHeaders },
  });
};

const checkRewrites = async (request: NextRequestWithAuth) => {
  const linkBaseURL = process.env.LINK_URL ?? "http://localhost:3000";
  logger.debug({ linkBaseURL }, "Link base URL");
  const opensearchBaseURL =
    process.env.OPENSEARCH_DASHBOARDS_URL ??
    "http://opensearch-dashboards:5601";

  const { token } = request.nextauth;
  const email = token?.email?.toLowerCase() ?? "unknown";
  const roles = (token?.roles as string[]) ?? [];
  let headers = {
    "x-forwarded-user": email,
    "x-forwarded-roles": roles.join(","),
  };

  if (request.nextUrl.pathname.startsWith("/dashboards")) {
    return rewriteURL(
      request,
      `${linkBaseURL}/dashboards`,
      opensearchBaseURL,
      headers,
    );
  } else {
    const isDev = process.env.NODE_ENV === "development";
    const nonce = Buffer.from(crypto.randomUUID()).toString("base64");
    const cspHeader = `
    default-src 'self';
    frame-src 'self' https://digiresilience.org;
    connect-src 'self';
    script-src 'self' 'nonce-${nonce}' 'strict-dynamic' ${isDev ? "'unsafe-eval'" : ""};
    style-src 'self' 'unsafe-inline';
    img-src 'self' blob: data:;
    font-src 'self';
    object-src 'none';
    base-uri 'self';
    form-action 'self';
    frame-ancestors 'self';
    upgrade-insecure-requests;
`;
    const contentSecurityPolicyHeaderValue = cspHeader
      .replace(/\s{2,}/g, " ")
      .trim();

    const requestHeaders = new Headers(request.headers);
    requestHeaders.set("x-nonce", nonce);
    requestHeaders.set(
      "Content-Security-Policy",
      contentSecurityPolicyHeaderValue,
    );

    const response = NextResponse.next({
      request: {
        headers: requestHeaders,
      },
    });

    response.headers.set(
      "Content-Security-Policy",
      contentSecurityPolicyHeaderValue,
    );

    return response;
  };
}

export default withAuth(checkRewrites, {
  callbacks: {
    authorized: ({ token, req }) => {
      if (process.env.SETUP_MODE === "true") {
        return true;
      }

      const path = req.nextUrl.pathname;
      const roles: any = token?.roles ?? [];

      if (path.startsWith("/login")) {
        return true;
      }

      if (path.startsWith("/admin") && !roles.includes("admin")) {
        return false;
      }

      if (roles.includes("admin") || roles.includes("agent")) {
        return true;
      }

      return false;
    },
  },
});

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