Asset locating in Symfony with cashed manifest contents.

AssetLocator.php

<?php


namespace App\Twig;

interface AssetLocator
{
    public function lookup(string $asset): string;
}

DevAssetLocator.php

  <?php

namespace App\Twig;

use function file_get_contents;
use function getenv;
use function json_decode;
use function ltrim;
use function pathinfo;
use const PATHINFO_EXTENSION;

class DevAssetLocator implements AssetLocator
{
    private $map = [];

    public function __construct()
    {
        if (\is_file(__DIR__ . '/../../../public/dist/manifest.json')) {
            $this->map = json_decode(file_get_contents(__DIR__ . '/../../../public/dist/manifest.json'), true);
        }
    }

    public function lookup(string $asset): string
    {
        if (getenv('USE_WEBPACK_DEV_SERVER') !== 'yes') {
            return $this->map[$asset] ?? '/' . ltrim($asset, '/');
        }

        $asset = ltrim($asset, '/');

        if (pathinfo($asset, PATHINFO_EXTENSION) === 'js') {
            $asset = 'dist/' . $asset;
        }

        return 'http://localhost:9001/' . ltrim($asset, '/');
    }
}

ProdAssetLocator.php

<?php

namespace App\Twig;

class ProdAssetLocator implements AssetLocator
{
    private $map = [];

    public function __construct(array $map = [])
    {
        $this->map = $map;
    }

    public function lookup(string $asset): string
    {
        return $this->map[$asset] ?? $asset;
    }
}

TwigExtension.php

<?php

namespace App\Twig;

use Twig\Extension\AbstractExtension;
use Twig\Extension\GlobalsInterface;
use Twig\TwigFilter;
use Twig_Function;

class TwigExtension extends AbstractExtension implements GlobalsInterface
{

    /**
     * @var AssetLocator
     */
    private $assetLocator;

    public function __construct(
        AssetLocator $assetLocator
    ) {
        $this->assetLocator = $assetLocator;
    }

    public function getFunctions()
    {
        return [
            new Twig_Function('asset_path', function (string $path) {
                return $this->assetLocator->lookup($path);
            }),
        ];
    }
}

UseProdAssetMapPass.php

<?php

namespace App\DependencyInjection;

use App\Twig\ProdAssetLocator;
use function file_get_contents;
use function json_decode;
use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\DependencyInjection\Definition;

class UseProdAssetMapPass implements CompilerPassInterface
{
    public function process(ContainerBuilder $container)
    {
        $definition = new Definition(ProdAssetLocator::class);
        $definition->setArgument(0, json_decode(file_get_contents(__DIR__.'/../../../public/dist/manifest.json'), true));
        $container->setDefinition('app.asset_locator', $definition);
    }
}