I'm attempting to add integrity attribute to a style I use for userscript Newspaper (ATOM/RDF/RSS)

Test page: https://mastodon.tedomum.net/@tedomum.rss

The error is this:

Refused to apply inline style because it violates the following Content Security Policy directive: "style-src 'self' https://mastodon.tedomum.net 'nonce-FF4fvS9IB+e83sIyujPoyw=='". Either the 'unsafe-inline' keyword, a hash ('sha256-JjOHpf1r2ZHN4jxJdiFIgopy2yA5l3DibXaFr1c70F4='), or a nonce ('nonce-...') is required to enable inline execution.

I used the output of these commands: (also used sha256)

cat FILENAME.js | openssl dgst -sha384 -binary | openssl base64 -A

shasum -b -a 384 FILENAME.js | awk '{ print $1 }' | xxd -r -p | base64
```

This is the part where integrity is applied:
```js
  if (isRTL) {
    stylesheet
    .textContent =
      stylesheet_ltr + stylesheet_rtl;
    stylesheet
      .setAttribute(
        'integrity',
        'I NEED HELP IN GETTING STRING CHECKSUM'
      );
  } else {
    stylesheet
    .textContent =
      stylesheet_ltr;
    stylesheet
      .setAttribute(
        'integrity',
        'I NEED HELP IN GETTING STRING CHECKSUM'
      );
  }

Please delete first post and this post

I'm attempting to add integrity attribute to a style I use for userscript Newspaper (ATOM/RDF/RSS)

Test page: https://mastodon.tedomum.net/@tedomum.rss

The error is this:

Refused to apply inline style because it violates the following Content Security Policy directive: "style-src 'self' https://mastodon.tedomum.net 'nonce-FF4fvS9IB+e83sIyujPoyw=='". Either the 'unsafe-inline' keyword, a hash ('sha256-JjOHpf1r2ZHN4jxJdiFIgopy2yA5l3DibXaFr1c70F4='), or a nonce ('nonce-...') is required to enable inline execution.

I used the output of these commands: (also used sha256)

cat FILENAME.js | openssl dgst -sha384 -binary | openssl base64 -A

shasum -b -a 384 FILENAME.js | awk '{ print $1 }' | xxd -r -p | base64

This is the part where integrity is applied:

  if (isRTL) {
    stylesheet
    .textContent =
      stylesheet_ltr + stylesheet_rtl;
    stylesheet
      .setAttribute(
        'integrity',
        'I NEED HELP IN GETTING STRING CHECKSUM'
      );
  } else {
    stylesheet
    .textContent =
      stylesheet_ltr;
    stylesheet
      .setAttribute(
        'integrity',
        'I NEED HELP IN GETTING STRING CHECKSUM'
      );
  }

Solved by:

function setNonceUponCSP() {
  window.addEventListener("securitypolicyviolation", (e) => {
    //let message = e.originalPolicy;
    //messageTruncated = message.substring(message.indexOf("'nonce-") + 7);
    //let nonceValue = messageTruncated.substring(0, messageTruncated.indexOf("'"));
    let nonceValue = e.originalPolicy.match(/'nonce-(.*?)'/)[1];
    cssStylesheet = document.getElementById(namespace);
    cssStylesheet.setAttribute('nonce', nonceValue);
  }, { passive : true, });
}

I didn't find a way to make it to work on first error.