updated to accept only .tar.zstd uploads

2026-09-23 17:48:42 +02:00
parent cf337483d7
commit c6b27cd3c9
15 changed files with 556 additions and 50 deletions
@@ -0,0 +1,52 @@
+using System.Formats.Tar;
+using System.IO;
+using ZstdSharp;
+
+namespace ParadoxSaveParser.WebAPI;
+
+/// <summary>
+/// Uploaded save is a zstd-compressed tar with files of the original save inside.
+/// Game data is stored in entry with name from <see cref="GameSaveEntryNames"/>.
+/// </summary>
+public static class SaveArchive
+{
+    public static Task<long> GetGameDataSize(IOPath archivePath, Game game, CancellationToken ct)
+    {
+        return WithGameDataEntry(archivePath, game, ct,
+            entry => Task.FromResult(entry.Length));
+    }
+
+    public static Task ExtractGameData(IOPath archivePath, Game game, Stream dest, long maxBytes,
+        CancellationToken ct)
+    {
+        return WithGameDataEntry(archivePath, game, ct, async entry =>
+        {
+            if (entry.Length > maxBytes)
+                throw new InvalidDataException(
+                    $"Game data size ({entry.Length} bytes) exceeds limit ({maxBytes} bytes)");
+            if (entry.DataStream is not null)
+                await entry.DataStream.CopyToAsync(dest, ct);
+            return true;
+        });
+    }
+
+    private static async Task<T> WithGameDataEntry<T>(IOPath archivePath, Game game, CancellationToken ct,
+        Func<TarEntry, Task<T>> action)
+    {
+        if (!GameSaveEntryNames.Map.TryGetValue(game, out string? entryName))
+            throw new ArgumentOutOfRangeException(nameof(game), game, "No game data entry name for game");
+
+        await using var file = File.OpenRead(archivePath);
+        await using var zstd = new DecompressionStream(file);
+        await using var tar = new TarReader(zstd);
+        while (await tar.GetNextEntryAsync(copyData: false, ct) is { } entry)
+        {
+            if (entry.EntryType is not (TarEntryType.RegularFile or TarEntryType.V7RegularFile))
+                continue;
+            if (System.IO.Path.GetFileName(entry.Name) == entryName)
+                return await action(entry);
+        }
+
+        throw new InvalidDataException($"Invalid save format: no '{entryName}' entry found");
+    }
+}