feat: add library scanning mechanic

2026-01-26 04:35:12 +01:00
parent 3a68531fb4
commit d46a2573c4
7 changed files with 355 additions and 14 deletions
--- a/Tools/MediaParser.cs
+++ b/Tools/MediaParser.cs
@@ -0,0 +1,126 @@
+using Microsoft.VisualBasic.FileIO;
+using Shadow.Data;
+using Shadow.Entities;
+using System.Security.Cryptography;
+
+namespace Shadow.Tools;
+
+public static class MediaParser
+{
+	/// <summary>
+	/// Generate a random hex string (with length 32 by default)
+	/// </summary>
+	/// <param name="length">Optional: hexstring length</param>
+	/// <returns>A hexstring of given length</returns>
+	public static string HexStr(int length = 32)
+	{
+		return RandomNumberGenerator.GetHexString(length).ToLower();
+	}
+
+	/// <summary>
+	/// Get metadata content opportunistically
+	/// </summary>
+	/// <param name="metadata">Dictionary to search in</param>
+	/// <param name="searchStrings">Keywords to search for</param>
+	/// <returns>Retrieved value (string) on success, otherwise null</returns>
+	public static string? GetAny(Dictionary<string, string> metadata, List<string> searchStrings)
+	{
+		foreach (string searchString in searchStrings)
+		{
+			if (metadata.TryGetValue(searchString, out string? value) && !string.IsNullOrEmpty(value))
+				return value;
+		}
+		return null;
+	}
+
+	/// <summary>
+	/// Map exiftool metadata to Song entity.
+	/// </summary>
+	/// <param name="db">Database context</param>
+	/// <param name="exif">ExifTool metadata</param>
+	/// <returns>New Song entity, or null if song already exists in db</returns>
+	public static Song? CreateSong(ApplicationDbContext db, Dictionary<string, string> exif)
+	{
+
+		// First of all, check if song already exists in db
+		string uri = GetAny(exif, ["_shadow:fileHash"])
+			?? throw new Exception("Fatal error: could not get file hash!");
+		if (db.Songs.FirstOrDefault(s => s.Uri == uri) != null) return null;
+
+		// If not, extract exif data
+		string title = GetAny(exif, [
+			"ItemList:Title",    // iTunes m4a
+			"ItemList:SortName", // iTunes m4a
+			"Vorbis:Title",      // Bandcamp ogg
+			"ID3v2_3:Title",     // Generic mp3/wav ID3 v2.3.0
+			])
+			?? Path.Combine(exif["System:Directory"], exif["System:FileName"]);
+		string filepath = Path.GetFullPath(
+			Path.Combine(exif["System:Directory"], exif["System:FileName"])
+			); // TODO: bulletproof this
+		string filetype = exif["File:FileType"].ToLower();
+
+		// Album/artist related
+		string artistName = GetAny(exif, [
+			"ItemList:Artist",        // iTunes m4a
+			"ItemList:AlbumArtist",   // iTunes m4a
+			"Vorbis:Artist",          // Bandcamp m4a
+			"Vorbis:Albumartist",     // Bandcamp m4a
+			"ID3v2_3:Artist",         // Generic mp3/wav ID3 v2.3.0
+			]) ?? "[Unknown Artist]"; // this is a weak line of defense against deliberately crafted 
+
+		string albumName = GetAny(exif, [
+			"ItemList:Album",        // iTunes m4a
+			"Vorbis:Album",          // Bandcamp m4a
+			"ID3v2_3:Album",         // Generic mp3/wav ID3 v2.3.0
+			]) ?? "[Unknown Album]"; // again, weak line of defense
+
+		// Try to find relevant artists and albums
+		Artist artist = db.Artists
+			.FirstOrDefault(a => a.NormalizedName == artistName.ToLower())
+			?? new Artist
+			{
+				Name = artistName,
+				NormalizedName = artistName.ToLower()
+			};
+
+		Album album = db.Albums
+			.FirstOrDefault(a => a.Name == albumName && a.Artist == artist)
+			?? new Album
+			{
+				Name = albumName,
+				Uri = HexStr(),
+				Artist = artist
+			};
+
+		Song song = new()
+		{
+			Title = title,
+			Uri = uri,
+			Filepath = filepath,
+			Filetype = filetype,
+			Album = album,
+			Artist = artist
+		};
+
+		try
+		{
+			// Is Update() safe here?
+			db.Artists.Update(artist);
+			db.Albums.Update(album);
+			db.Songs.Update(song);
+			artist.Albums.Add(album);
+			artist.Songs.Add(song);
+			db.SaveChanges();
+		}
+		catch (Exception e)
+		{
+			Console.WriteLine("[Error: MediaParser] Failed to extract metadata from {filepath}:\n" +
+				$"{e}");
+		}
+
+		return song;
+	}
+
+
+}