Add asset proxy

config/routes.yaml

@@ -3,3 +3,11 @@ storyblok.webhook:
     controller: Torr\Storyblok\Webhook\Controller\WebhookController::webhookEndpoint
     defaults:
         urlSecret: ~
+
+storyblok.asset-proxy:
+    path: /asset/{width}x{height}/{assetId}/{filename}
+    controller: Torr\Storyblok\Assets\Controller\AssetProxyController::proxyAsset
+    requirements:
+        width: \d*
+        height: \d*
+        assetId: \w+

config/services.yaml

@@ -22,3 +22,6 @@ services:
         $localeLevel: !abstract set via config
         $webhookSecret: !abstract set via config
         $allowUrlWebhookSecret: !abstract set via config
+
+    Torr\Storyblok\Assets\Proxy\AssetProxy:
+        $storagePath: '%kernel.project_dir%/var/storyblok/assets'

src/Assets/Controller/AssetProxyController.php

@@ -0,0 +1,40 @@
+<?php declare(strict_types=1);
+
+namespace Torr\Storyblok\Assets\Controller;
+
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpFoundation\ResponseHeaderBag;
+use Torr\Storyblok\Assets\Proxy\AssetProxy;
+
+/**
+ * @final
+ */
+class AssetProxyController extends AbstractController
+{
+	public function proxyAsset (
+		AssetProxy $assetProxy,
+		Request $request,
+		string $width,
+		string $height,
+		string $assetId,
+		string $filename,
+	) : Response
+	{
+		$path = \sprintf("%sx%s/%s/%s", $width, $height, $assetId, $filename);
+		$filePath = $assetProxy->getFilePath($path);
+
+		if (null === $filePath)
+		{
+			throw $this->createNotFoundException("File not found");
+		}
+
+		return $this->file(
+			$filePath,
+			disposition: $request->query->has("download")
+				? ResponseHeaderBag::DISPOSITION_ATTACHMENT
+				: ResponseHeaderBag::DISPOSITION_INLINE,
+		);
+	}
+}

src/Assets/Prox/AssetProxy.php

@@ -0,0 +1,126 @@
+<?php declare(strict_types=1);
+
+namespace Torr\Storyblok\Assets\Proxy;
+
+use Psr\Log\LoggerInterface;
+use Symfony\Component\Filesystem\Filesystem;
+use Symfony\Component\Filesystem\Path;
+use Symfony\Component\HttpClient\HttpOptions;
+use Symfony\Contracts\HttpClient\Exception\HttpExceptionInterface;
+use Symfony\Contracts\HttpClient\Exception\TransportExceptionInterface;
+use Symfony\Contracts\HttpClient\HttpClientInterface;
+use Torr\Storyblok\Api\ContentApi;
+use Torr\Storyblok\Config\StoryblokConfig;
+
+/**
+ * @final
+ */
+readonly class AssetProxy
+{
+	public function __construct (
+		private StoryblokConfig $config,
+		private HttpClientInterface $client,
+		private ContentApi $api,
+		private Filesystem $filesystem,
+		private string $storagePath,
+		private LoggerInterface $logger,
+	) {}
+
+	/**
+	 * Returns the file path of the proxied file
+	 */
+	public function getFilePath (string $path) : ?string
+	{
+		$targetPath = Path::join($this->storagePath, $path);
+
+		if (!is_file($targetPath))
+		{
+			$originUrl = \sprintf(
+				"https://a.storyblok.com/f/%s/%s?cv=%s",
+				$this->config->getSpaceId(),
+				ltrim($path, "/"),
+				$this->api->getSpaceInfo()->getCacheVersion(),
+			);
+
+			$this->logger->debug("Fetch proxied storyblok asset", [
+				"targetPath" => $targetPath,
+				"originUrl" => $originUrl,
+			]);
+
+			$success = $this->fetchFileFromOrigin($originUrl, $targetPath);
+
+			return $success
+				? $targetPath
+				: null;
+		}
+
+		$this->logger->debug("Found existing proxied storyblok asset", [
+			"targetPath" => $targetPath,
+		]);
+
+		return $targetPath;
+	}
+
+	/**
+	 * Fetches a fresh file from the origin
+	 *
+	 * @return bool whether the file was download correctly
+	 */
+	private function fetchFileFromOrigin (
+		string $originUrl,
+		string $targetPath,
+	) : bool
+	{
+		// ensure directory exists
+		$this->filesystem->mkdir(\dirname($targetPath));
+
+		// open file handle
+		$fileHandle = fopen($targetPath, "wb+");
+
+		if (!$fileHandle)
+		{
+			$this->logger->critical("Could not create proxied asset file on disk: {targetPath}", [
+				"targetPath" => $targetPath,
+			]);
+
+			return false;
+		}
+
+		try
+		{
+			// start request
+			$response = $this->client->request(
+				"GET",
+				$originUrl,
+				(new HttpOptions())
+					->buffer(false)
+					->toArray(),
+			);
+
+			// stream to file
+			foreach ($this->client->stream($response) as $chunk)
+			{
+				fwrite($fileHandle, $chunk->getContent());
+			}
+
+			fclose($fileHandle);
+
+			return true;
+		}
+		catch (TransportExceptionInterface|HttpExceptionInterface $exception)
+		{
+			$this->logger->error("Failed to fetch Storyblok asset {originUrl}: {message}", [
+				"message" => $exception->getMessage(),
+				"originUrl" => $originUrl,
+				"targetPath" => $targetPath,
+				"exception" => $exception,
+			]);
+
+			// be sure to close the file handle and clean up the incomplete file
+			fclose($fileHandle);
+			$this->filesystem->remove($targetPath);
+
+			return false;
+		}
+	}
+}