feat: preview generation

Signed-off-by: Sebastian Krupinski <krupinski01@gmail.com>

lib/Module.php

@@ -11,9 +11,19 @@ use KTXF\Module\ModuleInstanceAbstract;
 use KTXM\ServiceWopi\Console\CheckCommand;
 use KTXM\ServiceWopi\Console\CleanupCommand;
 use KTXM\ServiceWopi\Console\ConfigureCommand;
+use KTXC\Resource\ProviderManager;
+use KTXF\Resource\Provider\ProviderInterface;
+use KTXM\ServiceWopi\Preview\Provider;
 
 class Module extends ModuleInstanceAbstract
 {
+    public function __construct(private readonly ProviderManager $providers) {}
+
+    public function boot(): void
+    {
+        $this->providers->register(ProviderInterface::TYPE_PREVIEW, 'wopi', Provider::class);
+    }
+
     public function handle(): string { return 'service_wopi'; }
     public function label(): string { return 'WOPI Service'; }
     public function author(): string { return 'Ktrix'; }

lib/Preview/ConversionClient.php

@@ -0,0 +1,45 @@
+<?php
+declare(strict_types=1);
+namespace KTXM\ServiceWopi\Preview;
+
+use CURLStringFile;
+use KTXF\Preview\PreviewGenerationException;
+use KTXM\ServiceWopi\Discovery\ServerAddress;
+
+class ConversionClient
+{
+    public const MAX_RESPONSE_BYTES = 32 * 1024 * 1024;
+
+    public function pdf(ServerAddress $server, string $content, string $extension, string $mimeType): string
+    {
+        $curl = curl_init($server->url . '/cool/convert-to/pdf');
+        $pdf = '';
+        curl_setopt_array($curl, [
+            CURLOPT_POST => true,
+            CURLOPT_POSTFIELDS => ['data' => new CURLStringFile($content, 'document.' . $extension, $mimeType)],
+            CURLOPT_CONNECTTIMEOUT => 5,
+            CURLOPT_TIMEOUT => 30,
+            CURLOPT_FOLLOWLOCATION => false,
+            CURLOPT_PROTOCOLS => CURLPROTO_HTTPS,
+            CURLOPT_SSL_VERIFYPEER => true,
+            CURLOPT_SSL_VERIFYHOST => 2,
+            CURLOPT_HTTPHEADER => ['Accept: application/pdf'],
+            CURLOPT_WRITEFUNCTION => static function ($handle, string $chunk) use (&$pdf): int {
+                if (strlen($pdf) + strlen($chunk) > self::MAX_RESPONSE_BYTES) { return 0; }
+                $pdf .= $chunk;
+                return strlen($chunk);
+            },
+        ]);
+        try {
+            if (curl_exec($curl) === false) {
+                throw new PreviewGenerationException('WOPI conversion failed (cURL ' . curl_errno($curl) . ')');
+            }
+            if (curl_getinfo($curl, CURLINFO_RESPONSE_CODE) !== 200 || !str_starts_with($pdf, '%PDF-')) {
+                throw new PreviewGenerationException('WOPI conversion did not return a PDF');
+            }
+            return $pdf;
+        } finally {
+            curl_close($curl);
+        }
+    }
+}

lib/Preview/Provider.php

@@ -0,0 +1,92 @@
+<?php
+declare(strict_types=1);
+namespace KTXM\ServiceWopi\Preview;
+
+use Imagick;
+use KTXC\Context\TenantContextInterface;
+use KTXF\Preview\MimeType;
+use KTXF\Preview\PreviewGenerationException;
+use KTXF\Preview\PreviewRequest;
+use KTXF\Preview\PreviewResult;
+use KTXF\Preview\PreviewSource;
+use KTXF\Preview\Provider\PreviewProviderInterface;
+use KTXF\Resource\BinaryResource;
+use KTXF\Resource\Provider\ProviderInterface;
+use KTXM\ProviderPreviewImageMagick\Provider as ImageProvider;
+use KTXM\ServiceWopi\Host\WopiService;
+use Throwable;
+
+final class Provider implements PreviewProviderInterface
+{
+    public function __construct(
+        private readonly TenantContextInterface $tenant,
+        private readonly WopiService $wopi,
+        private readonly ConversionClient $client,
+        private readonly ImageProvider $images,
+    ) {}
+
+    public function type(): string { return ProviderInterface::TYPE_PREVIEW; }
+    public function identifier(): string { return 'wopi'; }
+    public function label(): string { return 'WOPI Office'; }
+    public function description(): string { return 'Generates first-page previews using the configured office server'; }
+    public function icon(): string { return 'file-document'; }
+    public function priority(): int { return 100; }
+
+    public function supports(string $sourceMimeType, PreviewRequest $request): bool
+    {
+        try {
+            if (!class_exists(Imagick::class)
+                || !in_array(MimeType::normalize($sourceMimeType), WopiService::FORMATS, true)
+                || !$this->images->supports('image/png', $request)) {
+                return false;
+            }
+            $this->wopi->configuration($this->tenant->requireIdentifier());
+            return true;
+        } catch (Throwable) {
+            return false;
+        }
+    }
+
+    public function generate(PreviewSource $source, PreviewRequest $request): PreviewResult
+    {
+        if (!$this->supports($source->mimeType, $request)) {
+            throw new PreviewGenerationException('WOPI does not support the requested preview conversion');
+        }
+        $config = $this->wopi->configuration($this->tenant->requireIdentifier());
+        $limit = min($request->maxSourceSize, $config->maxBytes);
+        if ($source->size !== null && $source->size > $limit) {
+            throw new PreviewGenerationException('Preview source exceeds the configured size limit');
+        }
+        $content = '';
+        foreach ($source->open()->stream() as $chunk) {
+            if (!is_string($chunk) || strlen($content) + strlen($chunk) > $limit) {
+                throw new PreviewGenerationException('Invalid or oversized preview source');
+            }
+            $content .= $chunk;
+        }
+        if ($content === '') { throw new PreviewGenerationException('Preview source is empty'); }
+
+        $pdf = $this->client->pdf($config->office, $content, array_search($source->mimeType, WopiService::FORMATS, true), $source->mimeType);
+        $file = tmpfile();
+        if ($file === false) { throw new PreviewGenerationException('Cannot create preview temporary file'); }
+        $image = new Imagick();
+        try {
+            if (fwrite($file, $pdf) !== strlen($pdf)) {
+                throw new PreviewGenerationException('Cannot write preview temporary file');
+            }
+            $image->setResolution(96, 96);
+            $image->readImage('pdf:' . stream_get_meta_data($file)['uri'] . '[0]');
+            $image->setImageFormat('png');
+            $png = $image->getImageBlob();
+            return $this->images->generate(new PreviewSource(
+                $source->sourceType, $source->identity, $source->signature, 'image/png', strlen($png),
+                static fn () => new BinaryResource('page.png', 'image/png', (static function () use ($png): \Generator { yield $png; })()),
+            ), new PreviewRequest($request->maxWidth, $request->maxHeight, $request->preferredMimeType, $request->quality, ConversionClient::MAX_RESPONSE_BYTES));
+        } catch (Throwable $error) {
+            throw new PreviewGenerationException('Could not render the office preview', previous: $error);
+        } finally {
+            $image->clear();
+            fclose($file);
+        }
+    }
+}