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Jon Stuebe

Social Images With Remix

December 28th, 2021

3 min read

How does it work?

If you're not familiar the overall process starts with a serverless function that runs a browser using something like puppeteer and takes a screenshot of the content and then sends that screenshot as the response for the serverless function.

A few of the guides used some puppeteer abstraction libraries that looked really nice but only worked on my local and had alot of issues when deployed to vercel (I'm assuming because of the puppeteer configuration). So, I decided to just get as bare bones as possible and use puppeteer directly.

So for starters you'll want to create a new "resource" route. In Remix this is basically just a route that doesn't export a default function but instead simply exports a LoaderFunction.

Install

First we'll install our devDependencies so that we can see this all functioning on our local machine.

yarn add --dev puppeteer

Next we'll install the dependencies to be used in production.

yarn add puppeteer-core chrome-aws-lambda

Loader

In your loader you'll want to some code so that your app knows which version of puppeteer to use:

export const loader: LoaderFunction = async ({ request, params }) => {
  let chrome: any = { args: [] };
  let puppeteer;

  if (process.env.AWS_LAMBDA_FUNCTION_VERSION) {
    chrome = require("chrome-aws-lambda");
    puppeteer = require("puppeteer-core");
  } else {
    puppeteer = require("puppeteer");
  }
  ...
}

Now that you have puppeteer ready to go, it's time to actually launch the browser, render content, and take the screenshot.

First let's launch the browser and set the viewport.

const browser = await puppeteer.launch({
  args: [...chrome.args, "--hide-scrollbars"],
  executablePath: chrome ? await chrome.executablePath : undefined,
});
const page = await browser.newPage();
// configure viewport
await page.setViewport({
  width: 1920,
  height: 1007,
  deviceScaleFactor: 1,
});

Next let's render our react component and then setup our html for the page. Note that you also need to include your css for your styles and fonts.

import { renderToString } from "react-dom/server";
import { SocialCard } from "~/components/SocialCard";

...
// post is loaded somewhere else in the loader function
const html = renderToString(
  <SocialCard
    title={post.title}
    image={post.image}
    readingTime={post.readingTime}
  />
);

await page.setContent(
  `<html class="font-sans"><head><link href="https://cdnjs.cloudflare.com/ajax/libs/inter-ui/3.19.3/inter.min.css" rel="stylesheet" /><link href="${css}" rel="stylesheet" /></head><body>${html}</body></html>`,
  {
    waitUntil: "networkidle0",
  }
);

Finally we take our screenshot and return our response with the correct Content-Type for a jpeg.

const screenshot = await page.screenshot({ type: "jpeg", quality: 100 });

return new Response(screenshot, {
  headers: {
    "Content-Type": "image/jpeg",
  },
});

Hopefully that helps you get off to a great start generating dynamic social images with Remix. As always hit me up on twitter if you have any questions.

© 2022 Jon Stuebe. All right reserved.