Pull the comedic engine ver thing

Signed-off-by: Mary <[email protected]>

Launcher.props

@@ -8,6 +8,6 @@
         3. Local dev SS14.Loader launching code.
         -->
         <TargetFramework>net8.0</TargetFramework>
-        <Version>0.25.1</Version>
+        <Version>0.26.0</Version>
     </PropertyGroup>
 </Project>

SS14.Launcher/ConfigConstants.cs

@@ -38,6 +38,10 @@ public static class ConfigConstants
     public const string RobustBuildsManifest = "https://central.spacestation14.io/builds/robust/manifest.json";
     public const string RobustModulesManifest = "https://central.spacestation14.io/builds/robust/modules.json";
 
+    // How long to keep cached copies of Robust manifests.
+    // TODO: Take this from Cache-Control header responses instead.
+    public static readonly TimeSpan RobustManifestCacheTime = TimeSpan.FromMinutes(15);
+
     public const string UrlOverrideAssets = "https://central.spacestation14.io/launcher/override_assets.json";
     public const string UrlAssetsBase = "https://central.spacestation14.io/launcher/assets/";
 

SS14.Launcher/Models/Data/CVars.cs

@@ -89,6 +89,22 @@ public static readonly CVarDef<bool> HasDismissedEarlyAccessWarning
     /// <seealso cref="ServerFilter.PlayerCountMax"/>
     public static readonly CVarDef<int> FilterPlayerCountMaxValue = CVarDef.Create("FilterPlayerCountMaxValue", 0);
 
+    /// <summary>
+    /// Enable local overriding of engine versions.
+    /// </summary>
+    /// <remarks>
+    /// If enabled and on a development build,
+    /// the launcher will pull all engine versions and modules from <see cref="EngineOverridePath"/>.
+    /// This can be set to <c>RobustToolbox/release/</c> to instantly pull in packaged engine builds.
+    /// </remarks>
+    public static readonly CVarDef<bool> EngineOverrideEnabled = CVarDef.Create("EngineOverrideEnabled", false);
+
+    /// <summary>
+    /// Path to load engines from when using <see cref="EngineOverrideEnabled"/>.
+    /// </summary>
+    public static readonly CVarDef<string> EngineOverridePath = CVarDef.Create("EngineOverridePath", "");
+
+
     // MarseyCVars start here
 
     // Stealthsey

SS14.Launcher/Models/EngineManager/EngineManagerDynamic.Manifest.cs

@@ -0,0 +1,117 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Net.Http.Json;
+using System.Text.Json.Serialization;
+using System.Threading;
+using System.Threading.Tasks;
+using Serilog;
+
+namespace SS14.Launcher.Models.EngineManager;
+
+public sealed partial class EngineManagerDynamic
+{
+    // This part of the code is responsible for downloading and caching the Robust build manifest.
+
+    private readonly SemaphoreSlim _manifestSemaphore = new(1);
+    private readonly Stopwatch _manifestStopwatch = Stopwatch.StartNew();
+
+    private Dictionary<string, VersionInfo>? _cachedRobustVersionInfo;
+    private TimeSpan _robustCacheValidUntil;
+
+    /// <summary>
+    /// Look up information about an engine version.
+    /// </summary>
+    /// <param name="version">The version number to look up.</param>
+    /// <param name="followRedirects">Follow redirections in version info.</param>
+    /// <param name="cancel">Cancellation token.</param>
+    /// <returns>
+    /// Information about the version, or null if it could not be found.
+    /// The returned version may be different than what was requested if redirects were followed.
+    /// </returns>
+    private async ValueTask<FoundVersionInfo?> GetVersionInfo(
+        string version,
+        bool followRedirects = true,
+        CancellationToken cancel = default)
+    {
+        await _manifestSemaphore.WaitAsync(cancel);
+        try
+        {
+            return await GetVersionInfoCore(version, followRedirects, cancel);
+        }
+        finally
+        {
+            _manifestSemaphore.Release();
+        }
+    }
+
+    private async ValueTask<FoundVersionInfo?> GetVersionInfoCore(
+        string version,
+        bool followRedirects,
+        CancellationToken cancel)
+    {
+        // If we have a cached copy, and it's not expired, we check it.
+        if (_cachedRobustVersionInfo != null && _robustCacheValidUntil > _manifestStopwatch.Elapsed)
+        {
+            // Check the version. If this fails, we immediately re-request the manifest as it may have changed.
+            // (Connecting to a freshly-updated server with a new Robust version, within the cache window.)
+            if (FindVersionInfoInCached(version, followRedirects) is { } foundVersionInfo)
+                return foundVersionInfo;
+        }
+
+        await UpdateBuildManifest(cancel);
+
+        return FindVersionInfoInCached(version, followRedirects);
+    }
+
+    private async Task UpdateBuildManifest(CancellationToken cancel)
+    {
+        // TODO: If-Modified-Since and If-None-Match request conditions.
+
+        Log.Debug("Loading manifest from {manifestUrl}...", ConfigConstants.RobustBuildsManifest);
+        _cachedRobustVersionInfo =
+            await _http.GetFromJsonAsync<Dictionary<string, VersionInfo>>(
+                ConfigConstants.RobustBuildsManifest, cancellationToken: cancel);
+
+        _robustCacheValidUntil = _manifestStopwatch.Elapsed + ConfigConstants.RobustManifestCacheTime;
+    }
+
+    private FoundVersionInfo? FindVersionInfoInCached(string version, bool followRedirects)
+    {
+        Debug.Assert(_cachedRobustVersionInfo != null);
+
+        if (!_cachedRobustVersionInfo.TryGetValue(version, out var versionInfo))
+            return null;
+
+        if (followRedirects)
+        {
+            while (versionInfo.RedirectVersion != null)
+            {
+                version = versionInfo.RedirectVersion;
+                versionInfo = _cachedRobustVersionInfo[versionInfo.RedirectVersion];
+            }
+        }
+
+        return new FoundVersionInfo(version, versionInfo);
+    }
+
+    private sealed record FoundVersionInfo(string Version, VersionInfo Info);
+
+    private sealed record VersionInfo(
+        bool Insecure,
+        [property: JsonPropertyName("redirect")]
+        string? RedirectVersion,
+        Dictionary<string, BuildInfo> Platforms);
+
+    private sealed class BuildInfo
+    {
+        [JsonInclude] [JsonPropertyName("url")]
+        public string Url = default!;
+
+        [JsonInclude] [JsonPropertyName("sha256")]
+        public string Sha256 = default!;
+
+        [JsonInclude] [JsonPropertyName("sig")]
+        public string Signature = default!;
+    }
+}