How can I check if redirected from Google in firebase authentication?

I'm now building an EC platform, integrating firebase authentication service. But I have a problem. I've used redirected method like following.

firebase.auth().signInWithRedirect(provider);

And I can get authentication result in the client side(browser) using firebase api, like this.

firebase.auth()
  .getRedirectResult()
  .then((result) => {
    if (result.credential) {
      ...
    }
    // The signed-in user info.
    var user = result.user;
  })

But I want to check in Server Side not in the browser, if the request was redirected from the Social OAuth Platform or else.

$_SERVER['HTTP_REFERER'] does not work, so I thought we can set redirect uri as a custom parameter, and check the uri in server side but setCustomParameters does not support redirect_uri. Is there any other api to set redirect_uri?