Harden YouTube search and download handling

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}`,
     );
@@ -78,8 +117,15 @@ export class YoutubeService {
     title: string,
     artist: string,
   ): Promise<void> {
-    if (coverUrl) {
+    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);
 
@@ -98,4 +144,3 @@ export class YoutubeService {
     );
   }
 }
-}

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

@@ -3,6 +3,16 @@ import { Job } from 'bullmq';
 import { TrackService } from './track.service';
 import { TrackEntity } from './track.entity';
 
+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')
 export class TrackDownloadProcessor extends WorkerHost {
   constructor(private readonly trackService: TrackService) {
@@ -10,7 +20,7 @@ export class TrackDownloadProcessor extends WorkerHost {
   }
 
   async process(job: Job<TrackEntity, void>): Promise<void> {
-    const maxPerMinute = Number(process.env.YT_DOWNLOADS_PER_MINUTE || 3);
+    const maxPerMinute = getDownloadsPerMinute();
     const sleepMs = Math.floor(60000 / maxPerMinute);
     await new Promise((res) => setTimeout(res, sleepMs));
     await this.trackService.downloadFromYoutube(job.data);

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

@@ -99,17 +99,24 @@ export class TrackService {
         error: String(err),
         status: TrackStatusEnum.Error,
       };
+      await this.update(track.id, updatedTrack);
+      return;
     }
+
+    await this.update(track.id, updatedTrack);
     await this.trackDownloadQueue.add('', updatedTrack, {
       jobId: `id-${updatedTrack.id}`,
     });
-    await this.update(track.id, updatedTrack);
   }
 
   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'}`,