A small modification to fruition.com script to allow having different SEO titles & descriptions depending on the path

notion-to-my-domain-cloudflare-worker.js

/* CONFIGURATION STARTS HERE */

/* Step 1: enter your domain name like fruitionsite.com */
const MY_DOMAIN = 'cryptoadvisor.club';
/*
 * Step 2: enter your URL slug to page ID mapping
 * The key on the left is the slug (without the slash)
 * The value on the right is the Notion page ID
 */
const SLUG_TO_PAGE = {
    '': 'notion-page-id-1',
    'path1': 'notion-page-id-2',
    'path2': 'notion-page-id-3'
};

/* Step 3: enter your page title and description for SEO purposes */
const PAGE_TITLE = {
    '/notion-page-id-1': 'SEO Title for page 1',
    '/notion-page-id-2': 'SEO Title for page 2',
    '/notion-page-id-3': 'SEO Title for page 3'
};
const PAGE_DESCRIPTION = {
    '/notion-page-id-1': 'SEO Description for page 1',
    '/notion-page-id-2': 'SEO Description for page 2',
    '/notion-page-id-3': 'SEO Description for page 3'
};

/* Step 4: enter a Google Font name, you can choose from https://fonts.google.com */
const GOOGLE_FONT = '';

/* Step 5: enter any custom scripts you'd like */
const CUSTOM_SCRIPT = ``;

/* CONFIGURATION ENDS HERE */

const PAGE_TO_SLUG = {};
const slugs = [];
const pages = [];
Object.keys(SLUG_TO_PAGE).forEach(slug => {
    const page = SLUG_TO_PAGE[slug];
    slugs.push(slug);
    pages.push(page);
    PAGE_TO_SLUG[page] = slug;
});

addEventListener('fetch', event => {
    event.respondWith(fetchAndApply(event.request));
});

function generateSitemap() {
    let sitemap = '<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">';
    slugs.forEach(
        (slug) =>
            (sitemap +=
                '<url><loc>https://' + MY_DOMAIN + '/' + slug + '</loc></url>')
    );
    sitemap += '</urlset>';
    return sitemap;
}

const corsHeaders = {
    'Access-Control-Allow-Origin': '*',
    'Access-Control-Allow-Methods': 'GET, HEAD, POST, PUT, OPTIONS',
    'Access-Control-Allow-Headers': 'Content-Type',
};

function handleOptions(request) {
    if (request.headers.get('Origin') !== null &&
        request.headers.get('Access-Control-Request-Method') !== null &&
        request.headers.get('Access-Control-Request-Headers') !== null) {
        // Handle CORS pre-flight request.
        return new Response(null, {
            headers: corsHeaders
        });
    } else {
        // Handle standard OPTIONS request.
        return new Response(null, {
            headers: {
                'Allow': 'GET, HEAD, POST, PUT, OPTIONS',
            }
        });
    }
}

async function fetchAndApply(request) {
    if (request.method === 'OPTIONS') {
        return handleOptions(request);
    }
    let url = new URL(request.url);
    url.hostname = 'www.notion.so';
    if (url.pathname === '/robots.txt') {
        return new Response('Sitemap: https://' + MY_DOMAIN + '/sitemap.xml');
    }
    if (url.pathname === '/sitemap.xml') {
        let response = new Response(generateSitemap());
        response.headers.set('content-type', 'application/xml');
        return response;
    }
    let fullPathname = request.url.replace("https://" + MY_DOMAIN, "");
    let response;
    if (url.pathname.startsWith('/app') && url.pathname.endsWith('js')) {
        response = await fetch(url.toString());
        let body = await response.text();
        response = new Response(body.replace(/www.notion.so/g, MY_DOMAIN).replace(/notion.so/g, MY_DOMAIN), response);
        response.headers.set('Content-Type', 'application/x-javascript');
        return response;
    } else if ((url.pathname.startsWith('/api'))) {
        // Forward API
        response = await fetch(url.toString(), {
            body: request.body,
            headers: {
                'content-type': 'application/json;charset=UTF-8',
                'user-agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.163 Safari/537.36'
            },
            method: 'POST',
        });
        response = new Response(response.body, response);
        response.headers.set('Access-Control-Allow-Origin', '*');
        return response;
    } else if (slugs.indexOf(url.pathname.slice(1)) > -1) {
        const pageId = SLUG_TO_PAGE[url.pathname.slice(1)];
        return Response.redirect('https://' + MY_DOMAIN + '/' + pageId, 301);
    } else {
        response = await fetch(url.toString(), {
            body: request.body,
            headers: request.headers,
            method: request.method,
        });
        response = new Response(response.body, response);
        response.headers.delete('Content-Security-Policy');
        response.headers.delete('X-Content-Security-Policy');
    }

    return appendJavascript(request, response, SLUG_TO_PAGE);
}

class MetaRewriter {
    constructor(req) {
        this.url = new URL(req.url);
    }

    element(element) {
        if (typeof PAGE_TITLE[this.url.pathname] !== 'undefined') {
            if (element.getAttribute('property') === 'og:title'
                || element.getAttribute('name') === 'twitter:title') {
                element.setAttribute('content', PAGE_TITLE[this.url.pathname]);
            }
            if (element.tagName === 'title') {
                element.setInnerContent(PAGE_TITLE[this.url.pathname]);
            }
        }
        if (typeof PAGE_DESCRIPTION[this.url.pathname] !== 'undefined') {
            if (element.getAttribute('name') === 'description'
                || element.getAttribute('property') === 'og:description'
                || element.getAttribute('name') === 'twitter:description') {
                element.setAttribute('content', PAGE_DESCRIPTION[this.url.pathname]);
            }
        }
        if (element.getAttribute('property') === 'og:url'
            || element.getAttribute('name') === 'twitter:url') {
            element.setAttribute('content', MY_DOMAIN);
        }
        if (element.getAttribute('name') === 'apple-itunes-app') {
            element.remove();
        }
    }
}

class HeadRewriter {
    element(element) {
        if (GOOGLE_FONT !== '') {
            element.append(`<link href="https://fonts.googleapis.com/css?family=${GOOGLE_FONT.replace(' ', '+')}:Regular,Bold,Italic&display=swap" rel="stylesheet">
        <style>* { font-family: "${GOOGLE_FONT}" !important; }</style>`, {
                html: true
            });
        }
        element.append(`<style>
      div.notion-topbar > div > div:nth-child(3) { display: none !important; }
      div.notion-topbar > div > div:nth-child(4) { display: none !important; }
      div.notion-topbar > div > div:nth-child(5) { display: none !important; }
      div.notion-topbar > div > div:nth-child(6) { display: none !important; }
      div.notion-topbar-mobile > div:nth-child(3) { display: none !important; }
      div.notion-topbar-mobile > div:nth-child(4) { display: none !important; }
      div.notion-topbar > div > div:nth-child(1n).toggle-mode { display: block !important; }
      div.notion-topbar-mobile > div:nth-child(1n).toggle-mode { display: block !important; }
      </style>`, {
            html: true
        })
    }
}

class BodyRewriter {
    constructor(SLUG_TO_PAGE) {
        this.SLUG_TO_PAGE = SLUG_TO_PAGE;
    }

    element(element) {
        element.append(`<div style="display:none">Powered by <a href="http://fruitionsite.com">Fruition</a></div>
      <script>
      const SLUG_TO_PAGE = ${JSON.stringify(this.SLUG_TO_PAGE)};
      const PAGE_TO_SLUG = {};
      const slugs = [];
      const pages = [];
      const el = document.createElement('div');
      let redirected = false;
      Object.keys(SLUG_TO_PAGE).forEach(slug => {
        const page = SLUG_TO_PAGE[slug];
        slugs.push(slug);
        pages.push(page);
        PAGE_TO_SLUG[page] = slug;
      });
      function getPage() {
        return location.pathname.slice(-32);
      }
      function getSlug() {
        return location.pathname.slice(1);
      }
      function updateSlug() {
        const slug = PAGE_TO_SLUG[getPage()];
        if (slug != null) {
          history.replaceState(history.state, '', '/' + slug);
        }
      }
      function onDark() {
        el.innerHTML = '<div style="margin-left: auto; margin-right: 14px; min-width: 0px;"><div role="button" tabindex="0" style="user-select: none; transition: background 120ms ease-in 0s; cursor: pointer; border-radius: 44px;"><div style="display: flex; flex-shrink: 0; height: 14px; width: 26px; border-radius: 44px; padding: 2px; box-sizing: content-box; background: rgb(46, 170, 220); transition: background 200ms ease 0s, box-shadow 200ms ease 0s;"><div style="width: 14px; height: 14px; border-radius: 44px; background: white; transition: transform 200ms ease-out 0s, background 200ms ease-out 0s; transform: translateX(12px) translateY(0px);"></div></div></div></div>';
        document.body.classList.add('dark');
        __console.environment.ThemeStore.setState({ mode: 'dark' });
      };
      function onLight() {
        el.innerHTML = '<div style="margin-left: auto; margin-right: 14px; min-width: 0px;"><div role="button" tabindex="0" style="user-select: none; transition: background 120ms ease-in 0s; cursor: pointer; border-radius: 44px;"><div style="display: flex; flex-shrink: 0; height: 14px; width: 26px; border-radius: 44px; padding: 2px; box-sizing: content-box; background: rgba(135, 131, 120, 0.3); transition: background 200ms ease 0s, box-shadow 200ms ease 0s;"><div style="width: 14px; height: 14px; border-radius: 44px; background: white; transition: transform 200ms ease-out 0s, background 200ms ease-out 0s; transform: translateX(0px) translateY(0px);"></div></div></div></div>';
        document.body.classList.remove('dark');
        __console.environment.ThemeStore.setState({ mode: 'light' });
      }
      function toggle() {
        if (document.body.classList.contains('dark')) {
          onLight();
        } else {
          onDark();
        }
      }
      function addDarkModeButton(device) {
        const nav = device === 'web' ? document.querySelector('.notion-topbar').firstChild : document.querySelector('.notion-topbar-mobile');
        el.className = 'toggle-mode';
        el.addEventListener('click', toggle);
        nav.appendChild(el);
        onLight();
      }
      const observer = new MutationObserver(function() {
        if (redirected) return;
        const nav = document.querySelector('.notion-topbar');
        const mobileNav = document.querySelector('.notion-topbar-mobile');
        if (nav && nav.firstChild && nav.firstChild.firstChild
          || mobileNav && mobileNav.firstChild) {
          redirected = true;
          updateSlug();
          addDarkModeButton(nav ? 'web' : 'mobile');
          const onpopstate = window.onpopstate;
          window.onpopstate = function() {
            if (slugs.includes(getSlug())) {
              const page = SLUG_TO_PAGE[getSlug()];
              if (page) {
                history.replaceState(history.state, 'bypass', '/' + page);
              }
            }
            onpopstate.apply(this, [].slice.call(arguments));
            updateSlug();
          };
        }
      });
      observer.observe(document.querySelector('#notion-app'), {
        childList: true,
        subtree: true,
      });
      const replaceState = window.history.replaceState;
      window.history.replaceState = function(state) {
        if (arguments[1] !== 'bypass' && slugs.includes(getSlug())) return;
        return replaceState.apply(window.history, arguments);
      };
      const pushState = window.history.pushState;
      window.history.pushState = function(state) {
        const dest = new URL(location.protocol + location.host + arguments[2]);
        const id = dest.pathname.slice(-32);
        if (pages.includes(id)) {
          arguments[2] = '/' + PAGE_TO_SLUG[id];
        }
        return pushState.apply(window.history, arguments);
      };
      const open = window.XMLHttpRequest.prototype.open;
      window.XMLHttpRequest.prototype.open = function() {
        arguments[1] = arguments[1].replace('${MY_DOMAIN}', 'www.notion.so');
        return open.apply(this, [].slice.call(arguments));
      };
    </script>${CUSTOM_SCRIPT}`, {
            html: true
        });
    }
}

async function appendJavascript(req, res, SLUG_TO_PAGE) {
    return new HTMLRewriter()
        .on('title', new MetaRewriter(req))
        .on('meta', new MetaRewriter(req))
        .on('head', new HeadRewriter())
        .on('body', new BodyRewriter(SLUG_TO_PAGE))
        .transform(res);
}