AlbumInfoLoader.kt

Each line, with the release that last changed it.

0.5.0	1	package dev.stave.upnp
	2
	3	import kotlinx.coroutines.Dispatchers
	4	import kotlinx.coroutines.withContext
	5	import okhttp3.OkHttpClient
	6	import okhttp3.Request
	7	import java.util.concurrent.TimeUnit
	8	import javax.inject.Inject
	9	import javax.inject.Singleton
	10
	11	/**
	12	* Locate prose notes for an album.
	13	*
	14	* Source priority:
	15	* 1. ID3 COMMENT / Vorbis DESCRIPTION embedded in the first track's
	16	* audio file. [AudioMetadataReader] surfaces these under the display
	17	* key "Comment". Most ripped-from-CD libraries store album reviews
	18	* and liner notes here.
	19	* 2. Sibling `.txt` file alongside the audio. A few UPnP servers
	20	* (notably MinimServer) expose adjacent filesystem entries; many do
	21	* not, in which case the fetch quietly 404s and we return null.
	22	*
	23	* The fetch is best-effort — both paths are wrapped in [runCatching] and
	24	* any failure (network, parse, missing tag) collapses to null. The UI
	25	* surfaces a generic "no information available" state when null comes back.
	26	*
	27	* No file caching beyond OkHttp's defaults: album views are short-lived,
	28	* the comment payload is at worst a few KB, and a stale-cache invalidation
	29	* story is more code than the savings justify.
	30	*/
	31	@Singleton
	32	class AlbumInfoLoader @Inject constructor(
	33	private val reader: AudioMetadataReader,
	34	) {
	35	private val http: OkHttpClient = OkHttpClient.Builder()
	36	.connectTimeout(5, TimeUnit.SECONDS)
	37	.readTimeout(15, TimeUnit.SECONDS)
	38	.writeTimeout(5, TimeUnit.SECONDS)
	39	.build()
	40
	41	/**
	42	* Returns the album-info text, or null when nothing is available.
	43	*
	44	* @param resourceUrl the streaming URL of any track in the album. ID3
	45	* tags are read from this URL directly; the sibling `.txt` lookup
	46	* replaces the trailing `.<ext>` with `.txt` and tries that.
	47	*/
	48	suspend fun load(resourceUrl: String): String? = withContext(Dispatchers.IO) {
	49	// 1. ID3 COMMENT / Vorbis DESCRIPTION via the existing reader.
	50	val tags = runCatching { reader.readTags(resourceUrl) }.getOrNull().orEmpty()
	51	val comment = tags["Comment"]?.takeIf { it.isNotBlank() }
	52	if (comment != null) return@withContext comment
	53
	54	// 2. Sibling .txt file. Try a couple of common review filename
	55	// patterns: same basename with .txt, plus generic "review.txt"
	56	// and "info.txt" in the same directory.
	57	val siblings = siblingTxtUrls(resourceUrl)
	58	for (url in siblings) {
	59	val body = fetchText(url)?.trim()
	60	if (!body.isNullOrEmpty()) return@withContext body
	61	}
	62	null
	63	}
	64
	65	/** Build candidate URLs for sibling `.txt` files. The UPnP resource URL
	66	* is typically `http://server:port/path/to/track.flac`; we replace the
	67	* filename with several common review-text conventions. Return order
	68	* matters — most-specific first so we don't pick up a generic
	69	* `review.txt` at a higher directory level when the album-specific
	70	* text is right next to the file. */
	71	private fun siblingTxtUrls(resourceUrl: String): List<String> {
	72	val slash = resourceUrl.lastIndexOf('/')
	73	if (slash <= 0) return emptyList()
	74	val dir = resourceUrl.substring(0, slash + 1)
	75	val filename = resourceUrl.substring(slash + 1)
	76	val basename = filename.substringBeforeLast('.', filename)
	77	return listOf(
	78	"$dir$basename.txt", // track-name.txt
	79	"${dir}review.txt", // album-folder/review.txt
	80	"${dir}info.txt", // album-folder/info.txt
	81	"${dir}notes.txt", // album-folder/notes.txt
	82	)
	83	}
	84
	85	private fun fetchText(url: String): String? {
	86	val req = Request.Builder().url(url).build()
	87	return runCatching {
	88	http.newCall(req).execute().use { r ->
	89	if (!r.isSuccessful) null else r.body?.string()
	90	}
	91	}.getOrNull()
	92	}
	93	}