calendar/apps/web/app/WithEmbedSSR.tsx

import type { GetServerSideProps, GetServerSidePropsContext } from "next";
import { notFound, redirect } from "next/navigation";

import { WebAppURL } from "@calcom/lib/WebAppURL";

export type EmbedProps = {
  isEmbed?: boolean;
};

const withEmbedSsrAppDir =
  <T extends Record<string, any>>(getServerSideProps: GetServerSideProps<T>) =>
  async (context: GetServerSidePropsContext): Promise<T> => {
    const { embed, layout } = context.query;
    const ssrResponse = await getServerSideProps(context);

    if ("redirect" in ssrResponse) {
      const destinationUrl = ssrResponse.redirect.destination;
      let urlPrefix = "";

      // Get the URL parsed from URL so that we can reliably read pathname and searchParams from it.
      const destinationUrlObj = new WebAppURL(ssrResponse.redirect.destination);

      // If it's a complete URL, use the origin as the prefix to ensure we redirect to the same domain.
      if (destinationUrl.search(/^(http:|https:).*/) !== -1) {
        urlPrefix = destinationUrlObj.origin;
      } else {
        // Don't use any prefix for relative URLs to ensure we stay on the same domain
        urlPrefix = "";
      }

      const destinationQueryStr = destinationUrlObj.searchParams.toString();
      // Make sure that redirect happens to /embed page and pass on embed query param as is for preserving Cal JS API namespace
      const newDestinationUrl = `${urlPrefix}${destinationUrlObj.pathname}/embed?${
        destinationQueryStr ? `${destinationQueryStr}&` : ""
      }layout=${layout}&embed=${embed}`;
      redirect(newDestinationUrl);
    }

    if ("notFound" in ssrResponse) {
      notFound();
    }

    return {
      ...ssrResponse.props,
      isEmbed: true,
    };
  };

export default withEmbedSsrAppDir;