Initial commit with Email Import Wizard and Task Processor updates

paperless-backend/src/email/email-page-cache.service.ts

@@ -0,0 +1,57 @@
+import { Injectable, Logger } from '@nestjs/common';
+import { ConfigService } from '@nestjs/config';
+import * as path from 'path';
+import * as fs from 'fs/promises';
+import sharp from 'sharp';
+
+const THUMBNAIL_WIDTH = 180;
+
+@Injectable()
+export class EmailPageCacheService {
+  private readonly logger = new Logger(EmailPageCacheService.name);
+  private readonly mailsRoot: string;
+
+  constructor(configService: ConfigService) {
+    this.mailsRoot = configService.get<string>('MAILS_DATA_DIR', '/mnt/data/mails');
+  }
+
+  attachmentDir(attachmentId: number | string): string {
+    return path.join(this.mailsRoot, attachmentId.toString());
+  }
+
+  previewPath(attachmentId: number | string, page: number): string {
+    return path.join(this.attachmentDir(attachmentId), `page-${page}.preview.png`);
+  }
+
+  thumbnailPath(attachmentId: number | string, page: number): string {
+    return path.join(this.attachmentDir(attachmentId), `page-${page}.thumb.png`);
+  }
+
+  async generate(attachmentId: number | string, renderedImages: string[]): Promise<void> {
+    const dir = this.attachmentDir(attachmentId);
+    await fs.mkdir(dir, { recursive: true });
+
+    for (let i = 0; i < renderedImages.length; i++) {
+      const page = i + 1;
+      const src = renderedImages[i];
+      const previewDest = this.previewPath(attachmentId, page);
+      const thumbDest = this.thumbnailPath(attachmentId, page);
+
+      try {
+        await fs.copyFile(src, previewDest);
+        await sharp(src).resize({ width: THUMBNAIL_WIDTH }).png().toFile(thumbDest);
+      } catch (err: any) {
+        this.logger.warn(`E-Mail Page Cache fehlgeschlagen (Attachment ${attachmentId} Seite ${page}): ${err.message}`);
+      }
+    }
+  }
+
+  async hasPreview(attachmentId: number | string, page: number): Promise<boolean> {
+    try {
+      await fs.access(this.previewPath(attachmentId, page));
+      return true;
+    } catch {
+      return false;
+    }
+  }
+}