Server-Side Rendering

By default the first visit arrives with an empty root element, and the client renders the page. With server-side rendering, the server sends the page already rendered, and the client hydrates it: faster first paint, and pages that read without JavaScript.

The rendering is done by Inertia's Node SSR server. Ssr\HttpGateway posts the page object to it over any PSR-18 client:

use Solo\Inertia\Ssr\HttpGateway;

new Inertia($rootView, ssr: new HttpGateway(
    $httpClient,        // Psr\Http\Client\ClientInterface
    $requestFactory,    // Psr\Http\Message\RequestFactoryInterface
    $streamFactory,     // Psr\Http\Message\StreamFactoryInterface
    url: 'http://127.0.0.1:13714/render',
    logger: $logger,
));

composer require psr/http-client   # with an implementation, such as solophp/http-client or guzzlehttp/guzzle

Only first visits are rendered on the server; Inertia visits get the page object as always. The gateway's head elements fill $head in the root template, and its body — the page object's script element and the rendered root element — replaces $body.

The SSR server

Follow the SSR guide of the Inertia documentation for the client side: with the @inertiajs/vite plugin, vite build --ssr builds the server bundle, and running it with node starts the server on port 13714. In development, the Vite dev server answers render requests itself at /__inertia_ssr:

url: $isDev ? 'http://localhost:5173/__inertia_ssr' : 'http://127.0.0.1:13714/render',

Failures

A render that fails never fails the request: the gateway logs a warning and returns null, and the page is rendered on the client, as without SSR. The log context has the component and URL, and what the SSR server says about the error — error, type (browser-api, component-resolution, render, or connection when the server could not be reached), hint, sourceLocation.

A gateway of your own

SsrGatewayInterface has one method, which returns the rendered markup or null:

use Solo\Inertia\Contracts\SsrGatewayInterface;
use Solo\Inertia\Ssr\RenderedPage;

final readonly class NoSsrOnAdminPages implements SsrGatewayInterface
{
    public function __construct(private SsrGatewayInterface $inner)
    {
    }

    public function render(array $page): ?RenderedPage
    {
        return str_starts_with((string) $page['component'], 'Admin/') ? null : $this->inner->render($page);
    }
}