Remix > Real-time updates

Live updates can be extremely useful both for content editors and the regular visitors of your app/website:

• Content-editors in Preview Mode can see drafts directly in the production website, without having to refresh the page;

• Visitors can immediately see new content as it gets published, allowing all kinds of real-time interactions with your website/app (ie. live-news coverage).

Inside a Remix project, it's extremely easy to use our Real-time Updates API to perform such changes, as it only involves adding a React hook to your page components.

How to use the useQuerySubscription hook

The react-datocms package exposes a useQuerySubscription hook that makes it trivial to update any Remix page in real-time.

The hook works by streaming any changes present to the response of a GraphQL query directly to the browser, and it a loader responsibility to prepare an object compatible with the options of the hook itself.

The following code shows a complete example that activates real-time updates for any visitor of your website:

import { useQuerySubscription } from "react-datocms";
import { load } from '~/lib/datocms';
export async function loader() {
  const graphqlRequest = {
    query: `query HomePage($limit: IntType) {
      allBlogPosts(first: $limit) {
        title
      }
    }`,
    variables: { limit: 10 },
  };
  return {
    subscription: {
      ...graphqlRequest,
      initialData: await load(graphqlRequest),
      token: process.env.DATOCMS_READONLY_TOKEN,
    },
  };
}
export default function Home({ subscription }) {
  const { data, error, status } = useQuerySubscription(subscription);
  const statusMessage = {
    connecting: 'Connecting to DatoCMS...',
    connected: 'Connected to DatoCMS, receiving live updates!',
    closed: 'Connection closed',
  };
  return (
    <div>
      <p>Connection status: {statusMessage[status]}</p>
      {error && (
        <div>
          <h1>Error: {error.code}</h1>
          <div>{error.message}</div>
          {error.response && (
            <pre>{JSON.stringify(error.response, null, 2)}</pre>
          )}
        </div>
      )}
      {data && (
        <div>{JSON.stringify(data, null, 2)}</div>
      )}
    </div>
  );
}

Preview Mode + useQuerySubscription

Another common scenario is being able to activate real-time updates of draft content only for content editors that are signed-in to the website via Preview Mode:

In this case, you don't want to expose your API token or pass down additional arguments to regular users, so:

• Make sure to pass the includeDrafts: true option only if Preview Mode is active (that is, if context.preview is true), so that only content editors will see draft content;

• If Preview Mode is off, fill in the subscription prop with just initialData and enabled: false options, without any additional clutter.

Here's an example snippet:

import { load } from '~/lib/datocms';
export async function loader({ request }) {
  const session = await getSession(request.headers.get('Cookie'));
  const previewModeActive = session.has('preview');
  const graphqlRequest = {
    query: `query HomePage($limit: IntType) {
      allBlogPosts(first: $limit) {
        title
      }
    }`,
    variables: { limit: 10 },
    includeDrafts: previewModeActive,
  };
  
  const initialData = await load(graphqlRequest);
  return {
    subscription: previewModeActive
      ? {
          ...graphqlRequest,
          initialData,
          token: process.env.DATOCMS_READONLY_TOKEN,
        }
      : {
        enabled: false,
        initialData,
      };
  };
}

If you want to directly see the final result, we've prepared a fully working Next.js blog, with real-time updates of draft content in Preview Mode:

Remix Blog

Remix Blog

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