Floatplane channel plugin for Jellyfin 10.10.x: browse, HLS proxy, cookie session, CI release

- IChannel: creators -> sub-channels -> video posts (public listing API, search mapped)
- IRequiresMediaInfoCallback -> signed proxy URLs; stream controller rewrites HLS so the
  AES-128 key is fetched server-side with the session cookie, segments stay on the CDN
- delivery/info cached per token lifetime and throttled (~2/min)
- config page: paste sails.sid + validate, extra creators, quality, search test
- scripts/package.sh -> plugin folder + zip + md5 + manifest.json; Gitea release workflow
- research docs, HAR analysis (HAR itself gitignored), install-pi5.sh

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

Jellyfin.Plugin.Floatplane/Playback/DeliveryResolver.cs

@@ -0,0 +1,194 @@
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+using Jellyfin.Plugin.Floatplane.Api;
+using Jellyfin.Plugin.Floatplane.Api.Models;
+using Jellyfin.Plugin.Floatplane.Configuration;
+using Microsoft.Extensions.Logging;
+
+namespace Jellyfin.Plugin.Floatplane.Playback;
+
+/// <summary>
+/// Calls <c>/api/v3/delivery/info</c> sparingly: results are cached until the signed
+/// token expires and calls are throttled to the configured budget (Floatplane allows
+/// roughly two per minute and answers 429 / Cloudflare 1015 beyond that).
+/// </summary>
+public class DeliveryResolver
+{
+    public const string ScenarioOnDemand = "onDemand";
+    public const string ScenarioDownload = "download";
+    public const string ScenarioLive = "live";
+
+    private readonly FloatplaneApiClient _api;
+    private readonly ILogger<DeliveryResolver> _logger;
+    private readonly Func<PluginConfiguration> _config;
+    private readonly ConcurrentDictionary<string, CachedDelivery> _cache = new(StringComparer.Ordinal);
+    private readonly SemaphoreSlim _throttle = new(1, 1);
+    private DateTimeOffset _lastCall = DateTimeOffset.MinValue;
+    private DateTimeOffset _blockedUntil = DateTimeOffset.MinValue;
+
+    public DeliveryResolver(FloatplaneApiClient api, ILogger<DeliveryResolver> logger)
+        : this(api, logger, () => Plugin.Instance?.Configuration ?? new PluginConfiguration())
+    {
+    }
+
+    public DeliveryResolver(FloatplaneApiClient api, ILogger<DeliveryResolver> logger, Func<PluginConfiguration> config)
+    {
+        _api = api;
+        _logger = logger;
+        _config = config;
+    }
+
+    public int CachedEntries => _cache.Count;
+
+    public DateTimeOffset LastCall => _lastCall;
+
+    /// <summary>Variants for an attachment, from cache when the token is still valid.</summary>
+    public async Task<IReadOnlyList<ResolvedVariant>> GetVariantsAsync(string scenario, string entityId, CancellationToken ct)
+    {
+        var key = scenario + "|" + entityId;
+        if (_cache.TryGetValue(key, out var cached) && cached.ExpiresAt > DateTimeOffset.UtcNow)
+        {
+            return cached.Variants;
+        }
+
+        await _throttle.WaitAsync(ct).ConfigureAwait(false);
+        try
+        {
+            if (_cache.TryGetValue(key, out cached) && cached.ExpiresAt > DateTimeOffset.UtcNow)
+            {
+                return cached.Variants;
+            }
+
+            var now = DateTimeOffset.UtcNow;
+            if (_blockedUntil > now)
+            {
+                throw new FloatplaneRateLimitException(_blockedUntil - now, "Floatplane delivery endpoint is rate-limited; retry later");
+            }
+
+            var perMinute = Math.Max(1, _config().DeliveryCallsPerMinute);
+            var minGap = TimeSpan.FromSeconds(60.0 / perMinute);
+            var wait = _lastCall + minGap - now;
+            if (wait > TimeSpan.Zero)
+            {
+                _logger.LogDebug("Throttling delivery/info for {Wait}", wait);
+                await Task.Delay(wait, ct).ConfigureAwait(false);
+            }
+
+            DeliveryInfoModel info;
+            try
+            {
+                _lastCall = DateTimeOffset.UtcNow;
+                info = await _api.GetDeliveryInfoAsync(scenario, entityId, ct).ConfigureAwait(false);
+            }
+            catch (FloatplaneRateLimitException ex)
+            {
+                _blockedUntil = DateTimeOffset.UtcNow + ex.RetryAfter;
+                throw;
+            }
+
+            var variants = info.Resolve().ToList();
+            var expires = variants
+                .Select(v => TokenExpiry(v.Url))
+                .Where(e => e.HasValue)
+                .Select(e => e!.Value)
+                .DefaultIfEmpty(DateTimeOffset.UtcNow.AddHours(1))
+                .Min()
+                .AddMinutes(-5);
+            _cache[key] = new CachedDelivery(variants, expires);
+            _logger.LogInformation(
+                "delivery/info {Scenario} {Entity}: {Count} variants ({Usable} usable), valid until {Expires:u}",
+                scenario,
+                entityId,
+                variants.Count,
+                variants.Count(v => v.IsUsable),
+                expires);
+            return variants;
+        }
+        finally
+        {
+            _throttle.Release();
+        }
+    }
+
+    /// <summary>
+    /// Picks the variant for a requested level name ("1080"): exact level, else the best
+    /// usable one not taller than requested, else the best usable one at all.
+    /// </summary>
+    public static ResolvedVariant? SelectVariant(IEnumerable<ResolvedVariant> variants, string requestedLevel)
+    {
+        var usable = variants.Where(v => v.IsUsable).ToList();
+        if (usable.Count == 0)
+        {
+            return null;
+        }
+
+        var wanted = DeliveryVariant.ParseHeight(requestedLevel);
+        var exact = usable.FirstOrDefault(v => string.Equals(v.Name, requestedLevel, StringComparison.OrdinalIgnoreCase)
+                                               || DeliveryVariant.ParseHeight(v.Name) == wanted);
+        if (exact != null)
+        {
+            return exact;
+        }
+
+        var notTaller = usable.Where(v => v.Height <= wanted).OrderByDescending(v => v.Height).ThenByDescending(v => v.Variant.Order).FirstOrDefault();
+        return notTaller ?? usable.OrderByDescending(v => v.Height).ThenByDescending(v => v.Variant.Order).First();
+    }
+
+    /// <summary>Reads <c>exp</c> from the JWT in a <c>?token=</c> query parameter, if any.</summary>
+    public static DateTimeOffset? TokenExpiry(string url)
+    {
+        if (!Uri.TryCreate(url, UriKind.Absolute, out var uri))
+        {
+            return null;
+        }
+
+        var query = uri.Query.TrimStart('?').Split('&', StringSplitOptions.RemoveEmptyEntries);
+        var token = query.Select(p => p.Split('=', 2)).FirstOrDefault(p => p[0] == "token" && p.Length == 2)?[1];
+        if (string.IsNullOrEmpty(token))
+        {
+            return null;
+        }
+
+        var parts = Uri.UnescapeDataString(token).Split('.');
+        if (parts.Length < 2)
+        {
+            return null;
+        }
+
+        try
+        {
+            var payload = Base64UrlDecode(parts[1]);
+            using var doc = JsonDocument.Parse(payload);
+            if (doc.RootElement.TryGetProperty("exp", out var exp) && exp.TryGetInt64(out var seconds))
+            {
+                return DateTimeOffset.FromUnixTimeSeconds(seconds);
+            }
+        }
+        catch (Exception ex) when (ex is FormatException or JsonException)
+        {
+            return null;
+        }
+
+        return null;
+    }
+
+    private static byte[] Base64UrlDecode(string s)
+    {
+        var padded = s.Replace('-', '+').Replace('_', '/');
+        switch (padded.Length % 4)
+        {
+            case 2: padded += "=="; break;
+            case 3: padded += "="; break;
+        }
+
+        return Convert.FromBase64String(padded);
+    }
+
+    private sealed record CachedDelivery(IReadOnlyList<ResolvedVariant> Variants, DateTimeOffset ExpiresAt);
+}