Auth with headers

export default {
  async fetch(request) {
    /**
     * @param {string} PRESHARED_AUTH_HEADER_KEY Custom header to check for key
     * @param {string} PRESHARED_AUTH_HEADER_VALUE Hard coded key value
     */
    const PRESHARED_AUTH_HEADER_KEY = "X-Custom-PSK";
    const PRESHARED_AUTH_HEADER_VALUE = "mypresharedkey";
    const psk = request.headers.get(PRESHARED_AUTH_HEADER_KEY);

    if (psk === PRESHARED_AUTH_HEADER_VALUE) {
      // Correct preshared header key supplied. Fetch request from origin.
      return fetch(request);
    }

    // Incorrect key supplied. Reject the request.
    return new Response("Sorry, you have supplied an invalid key.", {
      status: 403,
    });
  },
} satisfies ExportedHandler;