Auth with headers

Allow or deny a request based on a known pre-shared key in a header. This is not meant to replace the WebCrypto API.

/** * @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"
async function handleRequest(request) {  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,  })}
addEventListener("fetch", event => {  event.respondWith(handleRequest(event.request))})