refactor: streamline image handling by implementing direct streaming in BookService and ImageService, and update .gitignore to include temp directory

src/lib/services/image.service.ts

@@ -3,28 +3,34 @@ import { ERROR_CODES } from "../../constants/errorCodes";
 import { AppError } from "../../utils/errors";
 import logger from "@/lib/logger";
 
-export interface ImageResponse {
-  buffer: Buffer;
-  contentType: string | null;
-}
+// Cache HTTP navigateur : 30 jours (immutable car les thumbnails ne changent pas)
+const IMAGE_CACHE_MAX_AGE = 2592000;
 
 export class ImageService extends BaseApiService {
-  static async getImage(path: string): Promise<ImageResponse> {
+  /**
+   * Stream an image directly from Komga without buffering in memory
+   * Returns a Response that can be directly returned to the client
+   */
+  static async streamImage(
+    path: string,
+    cacheMaxAge: number = IMAGE_CACHE_MAX_AGE
+  ): Promise<Response> {
     try {
       const headers = { Accept: "image/jpeg, image/png, image/gif, image/webp, */*" };
 
-      // NE PAS mettre en cache - les images sont trop grosses et les Buffers ne sérialisent pas bien
       const response = await this.fetchFromApi<Response>({ path }, headers, { isImage: true });
-      const contentType = response.headers.get("content-type");
-      const arrayBuffer = await response.arrayBuffer();
-      const buffer = Buffer.from(arrayBuffer);
 
-      return {
-        buffer,
-        contentType,
-      };
+      // Stream the response body directly without buffering
+      return new Response(response.body, {
+        status: response.status,
+        headers: {
+          "Content-Type": response.headers.get("content-type") || "image/jpeg",
+          "Content-Length": response.headers.get("content-length") || "",
+          "Cache-Control": `public, max-age=${cacheMaxAge}, immutable`,
+        },
+      });
     } catch (error) {
-      logger.error({ err: error }, "Erreur lors de la récupération de l'image");
+      logger.error({ err: error }, "Erreur lors du streaming de l'image");
       throw new AppError(ERROR_CODES.IMAGE.FETCH_ERROR, {}, error);
     }
   }