feat: implement attachement preview

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

lib/Controllers/DefaultController.php

@@ -180,6 +180,7 @@ class DefaultController extends ControllerAbstract {
             'entity.copy' => throw new InvalidArgumentException('Operation not implemented: ' . $operation),
             'entity.submit' => $this->entitySubmit($tenantId, $userId, $data),
             'entity.download' => $this->entityDownload($tenantId, $userId, $data),
+            'entity.preview' => $this->entityPreview($tenantId, $userId, $data),
             'entity.blobs' => $this->entityBlobs($tenantId, $userId, $data),
             
             default => throw new InvalidArgumentException(self::ERR_INVALID_OPERATION . $operation)
@@ -968,4 +969,39 @@ class DefaultController extends ControllerAbstract {
         return $results;
     }
 
+    private function entityPreview(string $tenantId, string $userId, array $data): Response {
+        if (!isset($data['target']) || !is_string($data['target'])) {
+            throw new InvalidArgumentException(self::ERR_MISSING_TARGET);
+        }
+        if (!isset($data['part']) || !is_array($data['part'])) {
+            throw new InvalidArgumentException('Attachment preview requires a part');
+        }
+
+        $target = ResourceIdentifier::fromString($data['target']);
+        if (!$target instanceof EntityIdentifier) {
+            throw new InvalidArgumentException(self::ERR_INVALID_IDENTIFIER);
+        }
+        $preview = $this->manager->entityPreview(
+            $tenantId,
+            $userId,
+            $target,
+            $data['part'],
+            isset($data['variant']) && is_string($data['variant']) ? $data['variant'] : 'popover',
+        );
+        if ($preview === null) {
+            return new JsonResponse([
+                'status' => 'error',
+                'error' => ['code' => 404, 'message' => 'Preview unavailable'],
+            ], Response::HTTP_NOT_FOUND);
+        }
+
+        return new StreamedResponse($preview->result->resource->stream(), Response::HTTP_OK, [
+            'Content-Type' => $preview->result->resource->mimeType(),
+            'Content-Length' => (string) $preview->blob->size,
+            'ETag' => '"' . trim($preview->blob->etag, '"') . '"',
+            'Cache-Control' => 'private, max-age=3600',
+            'X-Content-Type-Options' => 'nosniff',
+        ]);
+    }
+
 }

lib/Manager.php

@@ -5,7 +5,10 @@ declare(strict_types=1);
 namespace KTXM\MailManager;
 
 use InvalidArgumentException;
+use KTXC\Preview\CachedPreview;
+use KTXC\Preview\PreviewManager;
 use KTXC\Resource\ProviderManager;
+use KTXF\Preview\PreviewSource;
 use KTXF\Mail\Collection\CollectionBaseInterface;
 use KTXF\Mail\Collection\CollectionPropertiesMutableInterface;
 use KTXF\Mail\Collection\ICollectionBase;
@@ -47,6 +50,7 @@ class Manager {
     public function __construct(
         private LoggerInterface $logger,
         private ProviderManager $providerManager,
+        private PreviewManager $previewManager,
     ) { }
 
     /**
@@ -934,13 +938,6 @@ class Manager {
         }
     }
 
-    public function entityDownload(string $tenantId, string $userId, EntityIdentifier $targetEntity, array|null $targetPart): BinaryResource {
-        // retrieve service
-        $service = $this->serviceFetch($tenantId, $userId, $targetEntity->provider(), $targetEntity->service());
-        // download entity
-        return $service->entityDownload($targetEntity, $targetPart);
-    }
-
     /**
      * Check if messages exist
      *
@@ -1352,4 +1349,49 @@ class Manager {
         return $service->entitySubmit($sender, $source, $message);
     }
 
+    public function entityDownload(string $tenantId, string $userId, EntityIdentifier $targetEntity, array|null $targetPart): BinaryResource {
+        // retrieve service
+        $service = $this->serviceFetch($tenantId, $userId, $targetEntity->provider(), $targetEntity->service());
+        // download entity
+        return $service->entityDownload($targetEntity, $targetPart);
+    }
+
+    /**
+     * Resolve an authorized attachment and lazily generate or retrieve its preview.
+     */
+    public function entityPreview(string $tenantId, string $userId, EntityIdentifier $targetEntity, array $part, string $variant = 'popover'): ?CachedPreview {
+        $mimeType = $part['type'] ?? null;
+        $size = $part['size'] ?? null;
+        if (!is_string($mimeType) || ($size !== null && !is_int($size))) {
+            throw new InvalidArgumentException('Attachment preview requires a MIME type and optional integer size');
+        }
+
+        $selector = array_filter([
+            'blobId' => $part['blobId'] ?? null,
+            'partId' => $part['partId'] ?? null,
+            'cid' => $part['cid'] ?? null,
+        ], static fn(mixed $value): bool => is_string($value) && $value !== '');
+        if ($selector === []) {
+            throw new InvalidArgumentException('Attachment preview requires a blob, part, or content identifier');
+        }
+
+        return $this->previewManager->fetch($tenantId, new PreviewSource(
+            sourceType: 'mail-attachment',
+            identity: (string) $targetEntity,
+            // Attachments are immutable once delivered, so there is no revision to track;
+            // existence and access are enforced by entityDownload() (via serviceFetch) below,
+            // which only runs on a cache miss.
+            signature: 'immutable',
+            mimeType: $mimeType,
+            size: $size,
+            resourceFactory: fn(): BinaryResource => $this->entityDownload(
+                $tenantId,
+                $userId,
+                $targetEntity,
+                $selector,
+            ),
+            selector: hash('sha256', json_encode($selector, JSON_THROW_ON_ERROR)),
+        ), $variant);
+    }
+
 }

src/services/entityService.ts

@@ -2,7 +2,7 @@
  * Entity management service
  */
 
-import { transceivePost, transceiveStream, transceiveDownload } from './transceive';
+import { transceivePost, transceiveStream, transceiveDownload, transceiveBlob } from './transceive';
 import type {
   EntityFetchRequest,
   EntityFetchResponse,
@@ -28,6 +28,7 @@ import type {
   EntityPatchResponse,
   EntityPatchRequest,
   EntityDownloadRequest,
+  EntityPreviewRequest,
   EntityBlobsRequest,
   EntityBlobsResponse,
   EntityBlobsWireResponse,
@@ -231,6 +232,10 @@ export const entityService = {
     return transceiveDownload<EntityDownloadRequest>('entity.download', request);
   },
 
+  async preview(request: EntityPreviewRequest): Promise<Blob> {
+    return await transceiveBlob<EntityPreviewRequest>('entity.preview', request);
+  },
+
   /**
    * Fetch one or more message parts (attachments) inline for rendering.
    *

src/services/transceive.ts

@@ -188,6 +188,25 @@ export function transceiveDownload<TRequest>(
   return { transaction: request.transaction };
 }
 
+export async function transceiveBlob<TRequest>(operation: string, data: TRequest): Promise<Blob> {
+  const request: ApiRequest<TRequest> = {
+    version: API_VERSION,
+    transaction: generateTransactionId(),
+    operation,
+    data,
+  };
+  let blob: Blob | null = null;
+  await fetchWrapper.post(API_URL, request, {
+    headers: { 'Accept': '*/*' },
+    onStream: async (response: Response) => {
+      blob = await response.blob();
+    },
+  });
+  if (blob === null) throw new Error(`[${operation}] Empty preview response`);
+  return blob;
+}
+
+
 function appendHiddenField(form: HTMLFormElement, name: string, value: string): void {
   const input = document.createElement('input');
   input.type = 'hidden';

src/stores/entitiesStore.ts

@@ -10,6 +10,7 @@ import type {
   EntityBlobSelector,
   EntityBlobsResponse,
   EntityDownloadRequest,
+  EntityPreviewRequest,
   EntityTransmitRequest,
   EntityTransmitResponse,
 } from '../types/entity'
@@ -518,6 +519,10 @@ export const useEntitiesStore = defineStore('mailEntitiesStore', () => {
     }
   }
 
+  async function preview(request: EntityPreviewRequest): Promise<Blob> {
+    return await entityService.preview(request)
+  }
+
   // Return public API
   return {
     // State (readonly)
@@ -540,6 +545,7 @@ export const useEntitiesStore = defineStore('mailEntitiesStore', () => {
     move,
     transmit,
     download,
+    preview,
     blobs,
   }
 })

src/types/entity.ts

@@ -227,6 +227,12 @@ export interface EntityDownloadRequest {
   filename?: string | null;
 }
 
+export interface EntityPreviewRequest {
+  target: EntityIdentifier;
+  part: EntityBlobSelector & { type: string; size?: number | null };
+  variant?: string;
+}
+
 export interface EntityBlobsRequest {
   target: EntityIdentifier;
   parts: EntityBlobSelector[];
@@ -246,4 +252,4 @@ export interface EntityBlobsResult extends Omit<EntityBlobsWireResult, 'bytes'>
   blob: Blob;
 }
 
-export interface EntityBlobsResponse extends Array<EntityBlobsResult> {}
+export interface EntityBlobsResponse extends Array<EntityBlobsResult> {}