Harden queue execution and job lifecycle

package-lock.json

@@ -11,6 +11,12 @@
         "src/backend",
         "src/frontend"
       ],
+      "dependencies": {
+        "@nestjs/throttler": "^6.5.0",
+        "class-transformer": "^0.5.1",
+        "class-validator": "^0.15.1",
+        "helmet": "^8.1.0"
+      },
       "devDependencies": {
         "@release-it/bumper": "^7.0.1",
         "auto-changelog": "^2.5.0",
@@ -6054,6 +6060,16 @@
         }
       }
     },
+    "node_modules/@nestjs/throttler": {
+      "version": "6.5.0",
+      "resolved": "https://registry.npmjs.org/@nestjs/throttler/-/throttler-6.5.0.tgz",
+      "integrity": "sha512-9j0ZRfH0QE1qyrj9JjIRDz5gQLPqq9yVC2nHsrosDVAfI5HHw08/aUAWx9DZLSdQf4HDkmhTTEGLrRFHENvchQ==",
+      "peerDependencies": {
+        "@nestjs/common": "^7.0.0 || ^8.0.0 || ^9.0.0 || ^10.0.0 || ^11.0.0",
+        "@nestjs/core": "^7.0.0 || ^8.0.0 || ^9.0.0 || ^10.0.0 || ^11.0.0",
+        "reflect-metadata": "^0.1.13 || ^0.2.0"
+      }
+    },
     "node_modules/@nestjs/typeorm": {
       "version": "10.0.2",
       "resolved": "https://registry.npmjs.org/@nestjs/typeorm/-/typeorm-10.0.2.tgz",
@@ -8241,6 +8257,11 @@
         "@types/superagent": "^8.1.0"
       }
     },
+    "node_modules/@types/validator": {
+      "version": "13.15.10",
+      "resolved": "https://registry.npmjs.org/@types/validator/-/validator-13.15.10.tgz",
+      "integrity": "sha512-T8L6i7wCuyoK8A/ZeLYt1+q0ty3Zb9+qbSSvrIVitzT3YjZqkTZ40IbRsPanlB4h1QB3JVL1SYCdR6ngtFYcuA=="
+    },
     "node_modules/@types/ws": {
       "version": "8.18.1",
       "resolved": "https://registry.npmjs.org/@types/ws/-/ws-8.18.1.tgz",
@@ -10472,6 +10493,21 @@
         "node": ">= 0.3.0"
       }
     },
+    "node_modules/class-transformer": {
+      "version": "0.5.1",
+      "resolved": "https://registry.npmjs.org/class-transformer/-/class-transformer-0.5.1.tgz",
+      "integrity": "sha512-SQa1Ws6hUbfC98vKGxZH3KFY0Y1lm5Zm0SY8XX9zbK7FJCyVEac3ATW0RIpwzW+oOfmHE5PMPufDG9hCfoEOMw=="
+    },
+    "node_modules/class-validator": {
+      "version": "0.15.1",
+      "resolved": "https://registry.npmjs.org/class-validator/-/class-validator-0.15.1.tgz",
+      "integrity": "sha512-LqoS80HBBSCVhz/3KloUly0ovokxpdOLR++Al3J3+dHXWt9sTKlKd4eYtoxhxyUjoe5+UcIM+5k9MIxyBWnRTw==",
+      "dependencies": {
+        "@types/validator": "^13.15.3",
+        "libphonenumber-js": "^1.11.1",
+        "validator": "^13.15.22"
+      }
+    },
     "node_modules/clean-stack": {
       "version": "2.2.0",
       "resolved": "https://registry.npmjs.org/clean-stack/-/clean-stack-2.2.0.tgz",
@@ -14399,6 +14435,14 @@
         "node": ">= 0.4"
       }
     },
+    "node_modules/helmet": {
+      "version": "8.1.0",
+      "resolved": "https://registry.npmjs.org/helmet/-/helmet-8.1.0.tgz",
+      "integrity": "sha512-jOiHyAZsmnr8LqoPGmCjYAaiuWwjAPLgY8ZX2XrmHawt99/u1y6RgrZMTeoPfpUbV96HOalYgz1qzkRbw54Pmg==",
+      "engines": {
+        "node": ">=18.0.0"
+      }
+    },
     "node_modules/himalaya": {
       "version": "1.1.1",
       "resolved": "https://registry.npmjs.org/himalaya/-/himalaya-1.1.1.tgz",
@@ -16929,6 +16973,11 @@
         "node": ">= 0.8.0"
       }
     },
+    "node_modules/libphonenumber-js": {
+      "version": "1.13.1",
+      "resolved": "https://registry.npmjs.org/libphonenumber-js/-/libphonenumber-js-1.13.1.tgz",
+      "integrity": "sha512-GEw0GLL7YUUA6nv21IsCvVjtI5Ejn84sjbdfQ9KxdbqEVOk1PZh7xejn01EEiniKw+dBeCfim+8MGeuvVuE2BA=="
+    },
     "node_modules/license-webpack-plugin": {
       "version": "4.0.2",
       "resolved": "https://registry.npmjs.org/license-webpack-plugin/-/license-webpack-plugin-4.0.2.tgz",
@@ -24476,6 +24525,14 @@
         "node": "^18.17.0 || >=20.5.0"
       }
     },
+    "node_modules/validator": {
+      "version": "13.15.35",
+      "resolved": "https://registry.npmjs.org/validator/-/validator-13.15.35.tgz",
+      "integrity": "sha512-TQ5pAGhd5whStmqWvYF4OjQROlmv9SMFVt37qoCBdqRffuuklWYQlCNnEs2ZaIBD1kZRNnikiZOS1eqgkar0iw==",
+      "engines": {
+        "node": ">= 0.10"
+      }
+    },
     "node_modules/vary": {
       "version": "1.1.2",
       "resolved": "https://registry.npmjs.org/vary/-/vary-1.1.2.tgz",
@@ -25704,7 +25761,7 @@
       "license": "MIT"
     },
     "src/backend": {
-      "version": "2.3.4",
+      "version": "2.4.2",
       "license": "UNLICENSED",
       "dependencies": {
         "@nestjs/bullmq": "^10.2.3",
@@ -25772,7 +25829,7 @@
       "license": "MIT"
     },
     "src/frontend": {
-      "version": "2.3.4",
+      "version": "2.4.2",
       "dependencies": {
         "@angular/animations": "^19.0.6",
         "@angular/common": "^19.0.6",

package.json

@@ -30,5 +30,11 @@
     "release-it": "^18.1.2",
     "release-it-docker-plugin": "^2.0.0",
     "rimraf": "^6.0.1"
+  },
+  "dependencies": {
+    "@nestjs/throttler": "^6.5.0",
+    "class-transformer": "^0.5.1",
+    "class-validator": "^0.15.1",
+    "helmet": "^8.1.0"
   }
 }

src/backend/.env.default

@@ -19,3 +19,9 @@ YT_DOWNLOADS_PER_MINUTE=3
 # Optional local hardening. Set AUTH_ENABLED=true and choose a strong token.
 AUTH_ENABLED=false
 SPOOTY_AUTH_TOKEN=
+
+
+# Optional frontend origin restriction
+CORS_ORIGIN=http://localhost:4200
+
+NODE_ENV=development

src/backend/.env.docker

@@ -17,3 +17,9 @@ YT_DOWNLOADS_PER_MINUTE=3
 # Optional local hardening. Set AUTH_ENABLED=true and choose a strong token.
 AUTH_ENABLED=false
 SPOOTY_AUTH_TOKEN=
+
+
+# Optional frontend origin restriction
+CORS_ORIGIN=http://localhost:4200
+
+NODE_ENV=production

src/backend/src/app.module.ts

@@ -13,6 +13,7 @@ import { EnvironmentEnum } from './environmentEnum';
 import { BullModule } from '@nestjs/bullmq';
 import { APP_GUARD } from '@nestjs/core';
 import { AuthGuard } from './shared/auth.guard';
+import { ThrottlerGuard, ThrottlerModule } from '@nestjs/throttler';
 
 @Module({
   imports: [
@@ -44,11 +45,30 @@ import { AuthGuard } from './shared/auth.guard';
       ],
       inject: [ConfigService],
     }),
+    ThrottlerModule.forRoot([
+      {
+        ttl: 60000,
+        limit: 60,
+      },
+    ]),
     BullModule.forRootAsync({
       imports: [ConfigModule],
       useFactory: async (configService: ConfigService) => ({
         defaultJobOptions: {
-          removeOnComplete: true,
+          attempts: 2,
+          backoff: {
+            type: 'exponential',
+            delay: 30_000,
+          },
+          removeOnComplete: {
+            age: 3_600,
+            count: 1_000,
+          },
+          removeOnFail: {
+            age: 86_400,
+            count: 1_000,
+          },
+          timeout: 10 * 60_000,
         },
         connection: {
           host: configService.get<string>(EnvironmentEnum.REDIS_HOST),
@@ -66,6 +86,10 @@ import { AuthGuard } from './shared/auth.guard';
       provide: APP_GUARD,
       useClass: AuthGuard,
     },
+    {
+      provide: APP_GUARD,
+      useClass: ThrottlerGuard,
+    },
   ],
 })
 export class AppModule {}

src/backend/src/environmentEnum.ts

@@ -10,4 +10,6 @@ export enum EnvironmentEnum {
   YT_COOKIES_FILE = 'YT_COOKIES_FILE',
   AUTH_ENABLED = 'AUTH_ENABLED',
   SPOOTY_AUTH_TOKEN = 'SPOOTY_AUTH_TOKEN',
+  CORS_ORIGIN = 'CORS_ORIGIN',
+  NODE_ENV = 'NODE_ENV',
 }

src/backend/src/main.ts

@@ -1,8 +1,11 @@
 import { NestFactory } from '@nestjs/core';
+import { ValidationPipe } from '@nestjs/common';
+import { HttpExceptionFilter } from './shared/filters/http-exception.filter';
 import { AppModule } from './app.module';
 import * as fs from 'fs';
 import { resolve } from 'path';
 import { exec } from 'child_process';
+import helmet from 'helmet';
 import { EnvironmentEnum } from './environmentEnum';
 
 function envFlag(name: string): boolean {
@@ -31,7 +34,41 @@ async function bootstrap() {
     }
   }
 
-  const app = await NestFactory.create(AppModule);
+  const app = await NestFactory.create(AppModule, {
+    bodyParser: true,
+  });
+
+  app.useGlobalPipes(
+    new ValidationPipe({
+      whitelist: true,
+      forbidNonWhitelisted: true,
+      transform: true,
+    }),
+  );
+
+  app.useGlobalFilters(new HttpExceptionFilter());
+
+  app.use(
+    helmet({
+      crossOriginResourcePolicy: false,
+    }),
+  );
+
+  const corsOrigin =
+    process.env[EnvironmentEnum.CORS_ORIGIN] || 'http://localhost:4200';
+
+  app.enableCors({
+    origin: corsOrigin,
+    credentials: false,
+  });
+
+  if (
+    process.env[EnvironmentEnum.NODE_ENV] === 'production' &&
+    !envFlag(EnvironmentEnum.AUTH_ENABLED)
+  ) {
+    console.warn('[SECURITY] AUTH_ENABLED is false while NODE_ENV=production');
+  }
+
   app.setGlobalPrefix('api');
   await app.listen(process.env.PORT || 3000);
 }

src/backend/src/playlist/dto/create-playlist.dto.ts

@@ -0,0 +1,11 @@
+import { IsString, IsUrl, MaxLength } from 'class-validator';
+
+export class CreatePlaylistDto {
+  @IsString()
+  @MaxLength(2048)
+  @IsUrl({
+    require_protocol: true,
+    protocols: ['https'],
+  })
+  spotifyUrl: string;
+}

src/backend/src/playlist/dto/update-playlist.dto.ts

@@ -0,0 +1,7 @@
+import { IsBoolean, IsOptional } from 'class-validator';
+
+export class UpdatePlaylistDto {
+  @IsOptional()
+  @IsBoolean()
+  active?: boolean;
+}

src/backend/src/playlist/playlist.controller.ts

@@ -4,11 +4,14 @@ import {
   Delete,
   Get,
   Param,
+  ParseIntPipe,
   Post,
   Put,
 } from '@nestjs/common';
 import { PlaylistService } from './playlist.service';
 import { PlaylistEntity } from './playlist.entity';
+import { CreatePlaylistDto } from './dto/create-playlist.dto';
+import { UpdatePlaylistDto } from './dto/update-playlist.dto';
 
 @Controller('playlist')
 export class PlaylistController {
@@ -20,25 +23,27 @@ export class PlaylistController {
   }
 
   @Post()
-  async create(@Body() playlist: PlaylistEntity): Promise<void> {
-    await this.service.create(playlist);
+  async create(@Body() playlist: CreatePlaylistDto): Promise<void> {
+    await this.service.create(playlist as PlaylistEntity);
   }
 
   @Put(':id')
   update(
-    @Param('id') id: number,
-    @Body() playlist: Partial<PlaylistEntity>,
+    @Param('id', ParseIntPipe) id: number,
+    @Body() playlist: UpdatePlaylistDto,
   ): Promise<void> {
     return this.service.update(id, playlist);
   }
 
   @Delete(':id')
-  remove(@Param('id') id: number): Promise<void> {
+  remove(@Param('id', ParseIntPipe) id: number): Promise<void> {
     return this.service.remove(id);
   }
 
   @Get('retry/:id')
-  retryFailedOfPlaylist(@Param('id') id: number): Promise<void> {
+  retryFailedOfPlaylist(
+    @Param('id', ParseIntPipe) id: number,
+  ): Promise<void> {
     return this.service.retryFailedOfPlaylist(id);
   }
 }

src/backend/src/playlist/playlist.service.ts

@@ -10,6 +10,7 @@ import { Interval } from '@nestjs/schedule';
 import { TrackStatusEnum } from '../track/track.entity';
 import { UtilsService } from '../shared/utils.service';
 import { SpotifyService } from '../shared/spotify.service';
+import { toSafeErrorMessage } from '../shared/errors/safe-error';
 
 enum WsPlaylistOperation {
   New = 'playlistNew',
@@ -77,7 +78,11 @@ export class PlaylistService {
       // Don't create folder structure for individual tracks - they go in root
     } catch (err) {
       this.logger.error(`Error getting track details: ${err}`);
-      playlist2Save = { ...playlist, error: String(err), isTrack: true };
+      playlist2Save = {
+        ...playlist,
+        error: toSafeErrorMessage(err),
+        isTrack: true,
+      };
     }
     const savedPlaylist = await this.save(playlist2Save);
 
@@ -117,7 +122,10 @@ export class PlaylistService {
       this.createPlaylistFolderStructure(playlist2Save.name);
     } catch (err) {
       this.logger.error(`Error getting playlist details: ${err}`);
-      playlist2Save = { ...playlist, error: String(err) };
+      playlist2Save = {
+        ...playlist,
+        error: toSafeErrorMessage(err),
+      };
     }
     const savedPlaylist = await this.save(playlist2Save);
 
@@ -224,7 +232,10 @@ export class PlaylistService {
         );
         this.createPlaylistFolderStructure(playlist.name);
       } catch (err) {
-        await this.update(playlist.id, { ...playlist, error: String(err) });
+        await this.update(playlist.id, {
+          ...playlist,
+          error: toSafeErrorMessage(err),
+        });
       }
       for (const track of tracks ?? []) {
         const track2Save = {

src/backend/src/shared/errors/safe-error.ts

@@ -0,0 +1,20 @@
+export function toSafeErrorMessage(error: unknown): string {
+  if (error instanceof Error) {
+    return sanitize(error.message);
+  }
+
+  if (typeof error === 'string') {
+    return sanitize(error);
+  }
+
+  return 'Unknown error';
+}
+
+function sanitize(text: string): string {
+  return text
+    .replace(/\/home\/[^\s]+/g, '[path]')
+    .replace(/\/root\/[^\s]+/g, '[path]')
+    .replace(/token=[^\s&]+/gi, 'token=[redacted]')
+    .replace(/authorization:[^\n]+/gi, 'authorization:[redacted]')
+    .slice(0, 500);
+}

src/backend/src/shared/filters/http-exception.filter.ts

@@ -0,0 +1,42 @@
+import {
+  ArgumentsHost,
+  Catch,
+  ExceptionFilter,
+  HttpException,
+  HttpStatus,
+  Logger,
+} from '@nestjs/common';
+import type { Request, Response } from 'express';
+
+@Catch()
+export class HttpExceptionFilter implements ExceptionFilter {
+  private readonly logger = new Logger(HttpExceptionFilter.name);
+
+  catch(exception: unknown, host: ArgumentsHost): void {
+    const ctx = host.switchToHttp();
+
+    const response = ctx.getResponse<Response>();
+    const request = ctx.getRequest<Request>();
+
+    const status =
+      exception instanceof HttpException
+        ? exception.getStatus()
+        : HttpStatus.INTERNAL_SERVER_ERROR;
+
+    const message =
+      exception instanceof HttpException
+        ? exception.message
+        : 'Internal server error';
+
+    this.logger.error(
+      `${request.method} ${request.url} -> ${status}: ${String(exception)}`,
+    );
+
+    response.status(status).json({
+      statusCode: status,
+      message,
+      timestamp: new Date().toISOString(),
+      path: request.url,
+    });
+  }
+}

src/backend/src/shared/youtube.service.ts

@@ -13,6 +13,14 @@ const HEADERS = {
     'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36',
 };
 
+const ALLOWED_YOUTUBE_HOSTS = new Set([
+  'youtube.com',
+  'www.youtube.com',
+  'm.youtube.com',
+  'music.youtube.com',
+  'youtu.be',
+]);
+
 @Injectable()
 export class YoutubeService {
   private readonly logger = new Logger(TrackService.name);
@@ -20,10 +28,37 @@ export class YoutubeService {
   constructor(private readonly configService: ConfigService) {}
 
   async findOnYoutubeOne(artist: string, name: string): Promise<string> {
-    this.logger.debug(`Searching ${artist} - ${name} on YT`);
-    const url = (await yts(`${artist} - ${name}`)).videos[0].url;
-    this.logger.debug(`Found ${artist} - ${name} on ${url}`);
-    return url;
+    const query = `${artist} - ${name}`;
+    this.logger.debug(`Searching ${query} on YT`);
+
+    const result = await yts(query);
+    const firstVideo = result.videos?.[0];
+
+    if (!firstVideo?.url) {
+      throw new Error(`No YouTube result found for: ${query}`);
+    }
+
+    this.assertValidYoutubeUrl(firstVideo.url);
+    this.logger.debug(`Found ${query} on ${firstVideo.url}`);
+    return firstVideo.url;
+  }
+
+  assertValidYoutubeUrl(url: string): void {
+    let parsed: URL;
+
+    try {
+      parsed = new URL(url);
+    } catch {
+      throw new Error('Invalid YouTube URL');
+    }
+
+    if (!['http:', 'https:'].includes(parsed.protocol)) {
+      throw new Error('Rejected non-HTTP YouTube URL');
+    }
+
+    if (!ALLOWED_YOUTUBE_HOSTS.has(parsed.hostname.toLowerCase())) {
+      throw new Error(`Rejected non-YouTube URL: ${parsed.hostname}`);
+    }
   }
 
   private getCookiesOptions(): {
@@ -51,10 +86,13 @@ export class YoutubeService {
     this.logger.debug(
       `Downloading ${track.artist} - ${track.name} (${track.youtubeUrl}) from YT`,
     );
+
     if (!track.youtubeUrl) {
-      this.logger.error('youtubeUrl is null or undefined');
-      throw Error('youtubeUrl is null or undefined');
+      throw new Error('youtubeUrl is null or undefined');
     }
+
+    this.assertValidYoutubeUrl(track.youtubeUrl);
+
     const ytdlp = new YtDlp();
     await ytdlp.downloadAudio(
       track.youtubeUrl,
@@ -67,6 +105,7 @@ export class YoutubeService {
         audioQuality: this.configService.get<string>('QUALITY'),
       },
     );
+
     this.logger.debug(
       `Downloaded ${track.artist} - ${track.name} to ${output}`,
     );
@@ -78,24 +117,30 @@ export class YoutubeService {
     title: string,
     artist: string,
   ): Promise<void> {
-    if (coverUrl) {
-      const res = await fetch(coverUrl);
-      const arrayBuf = await res.arrayBuffer();
-      const imageBuffer = Buffer.from(arrayBuf);
-
-      NodeID3.write(
-        {
-          title,
-          artist,
-          APIC: {
-            mime: 'image/jpeg',
-            type: { id: 3, name: 'front cover' },
-            description: 'cover',
-            imageBuffer,
-          },
-        },
-        folderName,
-      );
+    if (!coverUrl) {
+      return;
     }
+
+    const res = await fetch(coverUrl);
+    if (!res.ok) {
+      throw new Error(`Failed to fetch cover art: ${res.status}`);
+    }
+
+    const arrayBuf = await res.arrayBuffer();
+    const imageBuffer = Buffer.from(arrayBuf);
+
+    NodeID3.write(
+      {
+        title,
+        artist,
+        APIC: {
+          mime: 'image/jpeg',
+          type: { id: 3, name: 'front cover' },
+          description: 'cover',
+          imageBuffer,
+        },
+      },
+      folderName,
+    );
   }
 }

src/backend/src/track/track-download.processor.ts

@@ -1,17 +1,42 @@
 import { Processor, WorkerHost } from '@nestjs/bullmq';
+import { Logger } from '@nestjs/common';
 import { Job } from 'bullmq';
 import { TrackService } from './track.service';
 import { TrackEntity } from './track.entity';
 
-@Processor('track-download-processor')
+function getDownloadsPerMinute(): number {
+  const parsed = Number(process.env.YT_DOWNLOADS_PER_MINUTE || 3);
+
+  if (!Number.isFinite(parsed) || parsed <= 0) {
+    return 3;
+  }
+
+  return Math.max(1, Math.min(30, Math.floor(parsed)));
+}
+
+@Processor('track-download-processor', {
+  concurrency: 1,
+})
 export class TrackDownloadProcessor extends WorkerHost {
+  private readonly logger = new Logger(TrackDownloadProcessor.name);
+
   constructor(private readonly trackService: TrackService) {
     super();
   }
 
   async process(job: Job<TrackEntity, void>): Promise<void> {
-    const maxPerMinute = Number(process.env.YT_DOWNLOADS_PER_MINUTE || 3);
+    if (!job.data?.id) {
+      this.logger.warn(`Skipping malformed download job ${job.id}`);
+      return;
+    }
+
+    const maxPerMinute = getDownloadsPerMinute();
     const sleepMs = Math.floor(60000 / maxPerMinute);
+
+    this.logger.debug(
+      `Processing download job ${job.id} for track ${job.data.id}; pacing ${sleepMs}ms`,
+    );
+
     await new Promise((res) => setTimeout(res, sleepMs));
     await this.trackService.downloadFromYoutube(job.data);
   }

src/backend/src/track/track-search.processor.ts

@@ -1,15 +1,26 @@
 import { Processor, WorkerHost } from '@nestjs/bullmq';
+import { Logger } from '@nestjs/common';
 import { Job } from 'bullmq';
 import { TrackService } from './track.service';
 import { TrackEntity } from './track.entity';
 
-@Processor('track-search-processor')
+@Processor('track-search-processor', {
+  concurrency: 2,
+})
 export class TrackSearchProcessor extends WorkerHost {
+  private readonly logger = new Logger(TrackSearchProcessor.name);
+
   constructor(private readonly trackService: TrackService) {
     super();
   }
 
   async process(job: Job<TrackEntity, void, string>): Promise<void> {
+    if (!job.data?.id) {
+      this.logger.warn(`Skipping malformed search job ${job.id}`);
+      return;
+    }
+
+    this.logger.debug(`Processing search job ${job.id} for track ${job.data.id}`);
     await this.trackService.findOnYoutube(job.data);
   }
 }

src/backend/src/track/track.controller.ts

@@ -2,12 +2,14 @@ import {
   Controller,
   Delete,
   Get,
+  NotFoundException,
   Param,
+  ParseIntPipe,
   Res,
   StreamableFile,
 } from '@nestjs/common';
 import { TrackService } from './track.service';
-import { createReadStream } from 'fs';
+import { createReadStream, existsSync } from 'fs';
 import type { Response } from 'express';
 import { ConfigService } from '@nestjs/config';
 import { TrackEntity } from './track.entity';
@@ -20,33 +22,54 @@ export class TrackController {
   ) {}
 
   @Get('playlist/:id')
-  getAllByPlaylist(@Param('id') playlistId: number): Promise<TrackEntity[]> {
+  getAllByPlaylist(
+    @Param('id', ParseIntPipe) playlistId: number,
+  ): Promise<TrackEntity[]> {
     return this.service.getAllByPlaylist(playlistId);
   }
 
   @Get('download/:id')
   async getFile(
     @Res({ passthrough: true }) res: Response,
-    @Param('id') id: number,
+    @Param('id', ParseIntPipe) id: number,
   ): Promise<StreamableFile> {
     const track = await this.service.get(id);
+
+    if (!track || !track.playlist) {
+      throw new NotFoundException('Track not found');
+    }
+
+    const filePath = this.service.getFolderName(track, track.playlist);
+
+    if (!existsSync(filePath)) {
+      throw new NotFoundException('Track file not found');
+    }
+
     const fileName = this.service.getTrackFileName(track);
-    const readStream = createReadStream(
-      this.service.getFolderName(track, track.playlist),
-    );
+
+    const readStream = createReadStream(filePath);
+
     res.set({
-      'Content-Disposition': `attachment; filename="${encodeURIComponent(fileName)}`,
+      'Content-Disposition':
+        `attachment; filename="${encodeURIComponent(fileName)}"`,
+      'Content-Type': 'application/octet-stream',
+      'X-Content-Type-Options': 'nosniff',
     });
+
     return new StreamableFile(readStream);
   }
 
   @Delete(':id')
-  remove(@Param('id') id: number): Promise<void> {
+  remove(
+    @Param('id', ParseIntPipe) id: number,
+  ): Promise<void> {
     return this.service.remove(id);
   }
 
   @Get('retry/:id')
-  retry(@Param('id') id: number): Promise<void> {
+  retry(
+    @Param('id', ParseIntPipe) id: number,
+  ): Promise<void> {
     return this.service.retry(id);
   }
 }

src/backend/src/track/track.service.ts

@@ -12,6 +12,7 @@ import { UtilsService } from '../shared/utils.service';
 import { Queue } from 'bullmq';
 import { InjectQueue } from '@nestjs/bullmq';
 import { YoutubeService } from '../shared/youtube.service';
+import { toSafeErrorMessage } from '../shared/errors/safe-error';
 
 enum WsTrackOperation {
   New = 'trackNew',
@@ -57,9 +58,7 @@ export class TrackService {
 
   async create(track: TrackEntity, playlist?: PlaylistEntity): Promise<void> {
     const savedTrack = await this.repository.save({ ...track, playlist });
-    await this.trackSearchQueue.add('', savedTrack, {
-      jobId: `id-${savedTrack.id}`,
-    });
+    await this.enqueueSearch(savedTrack.id);
     this.io.emit(WsTrackOperation.New, {
       track: savedTrack,
       playlistId: playlist.id,
@@ -73,14 +72,30 @@ export class TrackService {
 
   async retry(id: number): Promise<void> {
     const track = await this.get(id);
-    await this.trackSearchQueue.add('', track, { jobId: `id-${id}` });
-    await this.update(id, { ...track, status: TrackStatusEnum.New });
+
+    if (!track) {
+      this.logger.warn(`Cannot retry missing track ${id}`);
+      return;
+    }
+
+    await this.enqueueSearch(id);
+    await this.update(id, {
+      ...track,
+      error: null,
+      status: TrackStatusEnum.New,
+    });
   }
 
   async findOnYoutube(track: TrackEntity): Promise<void> {
-    if (!(await this.get(track.id))) {
+    const dbTrack = await this.get(track.id);
+
+    if (!dbTrack) {
+      this.logger.warn(`Skipping search for missing track ${track.id}`);
       return;
     }
+
+    track = dbTrack;
+
     await this.update(track.id, {
       ...track,
       status: TrackStatusEnum.Searching,
@@ -96,20 +111,63 @@ export class TrackService {
       this.logger.error(err);
       updatedTrack = {
         ...track,
-        error: String(err),
+        error: toSafeErrorMessage(err),
         status: TrackStatusEnum.Error,
       };
+      await this.update(track.id, updatedTrack);
+      return;
     }
-    await this.trackDownloadQueue.add('', updatedTrack, {
-      jobId: `id-${updatedTrack.id}`,
-    });
+
     await this.update(track.id, updatedTrack);
+    await this.enqueueDownload(updatedTrack.id);
+  }
+
+  private async enqueueSearch(id: number): Promise<void> {
+    const track = await this.get(id);
+
+    if (!track) {
+      this.logger.warn(`Cannot enqueue search for missing track ${id}`);
+      return;
+    }
+
+    const jobId = `search-${id}`;
+    const existingJob = await this.trackSearchQueue.getJob(jobId);
+
+    if (existingJob) {
+      this.logger.warn(`Search job already exists for track ${id}`);
+      return;
+    }
+
+    await this.trackSearchQueue.add('search-track', { id }, { jobId });
+  }
+
+  private async enqueueDownload(id: number): Promise<void> {
+    const track = await this.get(id);
+
+    if (!track) {
+      this.logger.warn(`Cannot enqueue download for missing track ${id}`);
+      return;
+    }
+
+    const jobId = `download-${id}`;
+    const existingJob = await this.trackDownloadQueue.getJob(jobId);
+
+    if (existingJob) {
+      this.logger.warn(`Download job already exists for track ${id}`);
+      return;
+    }
+
+    await this.trackDownloadQueue.add('download-track', { id }, { jobId });
   }
 
   async downloadFromYoutube(track: TrackEntity): Promise<void> {
-    if (!(await this.get(track.id))) {
+    const dbTrack = await this.get(track.id);
+    if (!dbTrack) {
       return;
     }
+
+    track = dbTrack;
+
     if (!track.name || !track.artist || !track.playlist) {
       this.logger.error(
         `Track or playlist field is null or undefined: name=${track.name}, artist=${track.artist}, playlist=${track.playlist ? 'ok' : 'null'}`,
@@ -143,7 +201,7 @@ export class TrackService {
       }
     } catch (err) {
       this.logger.error(err);
-      error = String(err);
+      error = toSafeErrorMessage(err);
     }
 
     const updatedTrack = {