What is this?

Until recently server-side rendering in VueJS wasn't possible outside Node.js environments, as the rendering component used a number of node-specific functionality. However, with 2.5 the vue-server-renderer ships with a basic version of the rendering engine suitable for use on non-node environments like php-v8js and nashorn. This is a very simplified example of how to get server-side rendering working entirely within PHP in the context of a Symfony 4 application.

Prerequisites

• PHP 7.1+ with php-v8js module installed
  • brew gives an easy way to do this on OSX with brew install php71-v8js
• Composer 1.5.x
• Node 8.x
• Yarn 1.3.x

Getting Started

1. composer install to get PHP dependencies
2. yarn install to get JS dependencies
3. yarn run dev to build JS files (or yarn run watch for interactive watch)
4. php bin/console server:run to start a PHP server on 127.0.0.1:8000

Explanation

In broad strokes this works by:

• calling RenderService::render() to run the vue app code in php-v8js
  • as part of this window.__INITIAL_STATE__ is filled with the server-generated app state
• outputting the result as a string, which is passed to app.html.twig to generate the page
• VueJS boots in the browser, sees data-server-rendered="true" on the root node and performs hydration based on that and window.__INITIAL_STATE__

Caveats

The biggest outstanding issue with this is that the server isn't calling the /number endpoint to pre-fetch data, but hardcoding a starting value instead. This could definitely be improved by creating a generic API layer that can do both browser and server based calls with the same function.

The other issue is that this setup is tricky to develop with - the php-v8js module doesn't deal with parsing errors very well, and I often found myself having to manually kill browser tabs to stop them running up 100% CPU usage when something went wrong. Hopefully this'll improve over time as it matures.

After having had to solve this problem in a high-throughput production environment my recommendation would be to use a serverless SSR service (or standalone node server) and ESI to include it into your PHP application. While this brings other complications, it's a far more robust setup.