feat: Add URL validation before file downloads and ensure valid session IDs for tracks and streams. (#813)

src/api/mutations/download/offlineModeUtils.ts

@@ -60,6 +60,11 @@ export async function downloadJellyfinFile(
 	setDownloadProgress: JellifyDownloadProgressState,
 	preferredExtension?: string | null,
 ): Promise<DownloadedFileInfo> {
+	// Validate URL before attempting download to prevent NPE in native code
+	if (!url || url.trim() === '') {
+		throw new Error('Invalid download URL: URL is empty or undefined')
+	}
+
 	try {
 		const urlExtension = normalizeExtension(getExtensionFromUrl(url))
 		const hintedExtension = normalizeExtension(preferredExtension)
@@ -168,6 +173,12 @@ export const saveAudio = async (
 		//Ignore
 	}
 
+	// Validate track URL before attempting download
+	if (!track.url || track.url.trim() === '') {
+		console.error('Cannot download track: URL is missing', track.item.Id)
+		return false
+	}
+
 	try {
 		const downloadedTrackFile = await downloadJellyfinFile(
 			track.url,
@@ -177,10 +188,11 @@ export const saveAudio = async (
 			track.mediaSourceInfo?.Container,
 		)
 		let downloadedArtworkFile: DownloadedFileInfo | undefined
-		if (track.artwork) {
+		// Check for non-empty artwork URL (empty string passes truthy check but fails download)
+		if (track.artwork && typeof track.artwork === 'string' && track.artwork.trim() !== '') {
 			downloadedArtworkFile = await downloadJellyfinFile(
-				track.artwork as string,
-				track.item.Id as string,
+				track.artwork,
+				`${track.item.Id}-artwork`,
 				track.title as string,
 				setDownloadProgress,
 				undefined,

src/utils/mappings.ts

@@ -23,6 +23,18 @@ import StreamingQuality from '../enums/audio-quality'
 import { getAudioCache } from '../api/mutations/download/offlineModeUtils'
 import RNFS from 'react-native-fs'
 
+/**
+ * Ensures a valid session ID is returned.
+ * The ?? operator doesn't catch empty strings, so we need this helper.
+ * Empty session IDs cause MusicService to crash with "Session ID must be unique. ID="
+ */
+function getValidSessionId(sessionId: string | null | undefined): string {
+	if (sessionId && sessionId.trim() !== '') {
+		return sessionId
+	}
+	return uuid.v4().toString()
+}
+
 /**
  * Gets the artwork URL for a track, prioritizing the track's own artwork over the album's artwork.
  * Falls back to artist image if no album artwork is available.
@@ -169,16 +181,21 @@ function ensureFileUri(path?: string): string | undefined {
 }
 
 function buildDownloadedTrack(downloadedTrack: JellifyDownload): TrackMediaInfo {
+	// Safely build the image path - artwork is optional and may be undefined
+	const imagePath = downloadedTrack.artwork
+		? `file://${RNFS.DocumentDirectoryPath}/${downloadedTrack.artwork.split('/').pop()}`
+		: undefined
+
 	return {
 		type: TrackType.Default,
 		url: `file://${RNFS.DocumentDirectoryPath}/${downloadedTrack.path!.split('/').pop()}`,
-		image: `file://${RNFS.DocumentDirectoryPath}/${downloadedTrack.artwork!.split('/').pop()}`,
+		image: imagePath,
 		duration: convertRunTimeTicksToSeconds(
 			downloadedTrack.mediaSourceInfo?.RunTimeTicks || downloadedTrack.item.RunTimeTicks || 0,
 		),
 		item: downloadedTrack.item,
 		mediaSourceInfo: downloadedTrack.mediaSourceInfo,
-		sessionId: downloadedTrack.sessionId,
+		sessionId: getValidSessionId(downloadedTrack.sessionId),
 		sourceType: 'download',
 	}
 }
@@ -198,7 +215,7 @@ function buildTranscodedTrack(
 		duration: convertRunTimeTicksToSeconds(RunTimeTicks ?? 0),
 		mediaSourceInfo,
 		item,
-		sessionId,
+		sessionId: getValidSessionId(sessionId),
 		sourceType: 'stream',
 	}
 }
@@ -228,7 +245,7 @@ function buildAudioApiUrl(
 		const mediaSource = mediaInfo!.MediaSources![0]
 
 		urlParams = {
-			playSessionId: mediaInfo?.PlaySessionId ?? uuid.v4(),
+			playSessionId: getValidSessionId(mediaInfo?.PlaySessionId),
 			startTimeTicks: '0',
 			static: 'true',
 		}