refactor: Unify OSS update path through OSSUpdateStrategy (#414)

* refactor: unify OSS update path through OSSUpdateStrategy

Move client-side OSS logic (version config download, upgrade check,
process launch) from LaunchOssAsync() into OSSUpdateStrategy. The
strategy now handles both client and upgrade OSS roles internally.

- OSSUpdateStrategy.ExecuteAsync(): detects role via
  GlobalConfigInfoOSS env var, dispatches to ExecuteClientAsync()
  or ExecuteUpgradeAsync() accordingly
- GeneralUpdateBootstrap: AppType.OSS now goes through
  LaunchWithStrategy(new OSSUpdateStrategy()) — consistent with
  Client and Upgrade paths
- Deleted LaunchOssAsync(), DownloadOssFile(), IsOssUpgrade() from
  GeneralUpdateBootstrap

Closes #409

* refactor: simplify OSS to single-process flow, remove upgrade/client split

OSS mode no longer needs a separate upgrade process. The strategy
downloads version config, downloads packages from OSS, decompresses,
starts the main app, and exits — all in one process.

- Removed client/upgrade env-var-based dispatch from OSSUpdateStrategy
- Single ExecuteAsync() flow: download config -> download packages -> decompress -> start app -> exit
- Removed GlobalConfigInfoOSS env var bridging (no longer needed)

Related #409

* refactor: OSS client/upgrade split with upgrade process

OSS mode uses a separate upgrade process to download packages and
decompress, but does NOT check UpgradeClientVersion (the upgrade
process itself never needs upgrading — differs from standard flow).

Client side (main app):
  Download version config → check update → start upgrade process → exit

Upgrade side (GeneralUpdate.Upgrade.exe):
  Read version config → download OSS packages → decompress → start main app

Related #409

* refactor: add AppType.OSSClient/OSSUpgrade, remove env-var dispatch

Replace AppType.OSS with explicit OSSClient/OSSUpgrade to match the
Client/Upgrade pattern. OSSUpdateStrategy now accepts AppType via
constructor instead of detecting role via GlobalConfigInfoOSS env var.

- AppType enum: OSS = 3 -> OSSClient = 3, OSSUpgrade = 4
- Bootstrap dispatch: OSSClient/OSSUpgrade through LaunchWithStrategy
- OSSUpdateStrategy: role dispatched by constructor AppType parameter
- Updated tests for new enum values

Closes #409

* fix: remove dead GlobalConfigInfoOSS write from OSS client path

The upgrade side (ExecuteUpgradeAsync) reads version config directly
from the local JSON file — it never reads GlobalConfigInfoOSS env var.
Writing it in ExecuteClientAsync was dead code.

Removed ossConfig + Environments.SetEnvironmentVariable block.

Related #409

* fix: guard against empty UpdateUrl in OSS client download

DownloadVersionConfig calls HttpClient which throws
InvalidOperationException when UpdateUrl is empty/null. Skip the
download when UpdateUrl is not configured, then check for local
version config file existence as before.

Fixes OssIntegrationTests.OSSUpdateStrategy_RequiresConfig test.

Related #409

Author: JusterZhu

src/c#/GeneralUpdate.Core/Bootstrap/GeneralUpdateBootstrap.cs

@@ -27,7 +27,8 @@ namespace GeneralUpdate.Core;
 /// <list type="bullet">
 ///   <item><see cref="AppType.Client"/> — validate versions, download, start upgrade process</item>
 ///   <item><see cref="AppType.Upgrade"/> — receive ProcessInfo, apply updates, start main app</item>
-///   <item><see cref="AppType.OSS"/> — OSS-based cloud storage update</item>
+///   <item><see cref="AppType.OSSClient"/> — OSS client: download version config, start upgrade process</item>
+///   <item><see cref="AppType.OSSUpgrade"/> — OSS upgrade: download packages from cloud, start main app</item>
 /// </list>
 /// </summary>
 /// <remarks>
@@ -71,7 +72,8 @@ public override async Task<GeneralUpdateBootstrap> LaunchAsync()
         {
             AppType.Client  => await LaunchWithStrategy(new ClientUpdateStrategy()),
             AppType.Upgrade => await LaunchWithStrategy(new UpgradeUpdateStrategy()),
-            AppType.OSS     => await LaunchOssAsync(),
+            AppType.OSSClient  => await LaunchWithStrategy(new OSSUpdateStrategy(AppType.OSSClient)),
+            AppType.OSSUpgrade => await LaunchWithStrategy(new OSSUpdateStrategy(AppType.OSSUpgrade)),
             _ => await LaunchWithStrategy(new ClientUpdateStrategy())
         };
     }
@@ -153,73 +155,6 @@ private async Task<GeneralUpdateBootstrap> LaunchWithStrategy(IStrategy roleStra
         return this;
     }
 
-    /// <summary>OSS workflow: download packages from cloud storage, apply updates.</summary>
-    private async Task<GeneralUpdateBootstrap> LaunchOssAsync()
-    {
-        try
-        {
-            GeneralTracer.Debug("LaunchOssAsync start.");
-
-            var json = Environments.GetEnvironmentVariable("GlobalConfigInfoOSS");
-            if (!string.IsNullOrWhiteSpace(json))
-            {
-                var strategy = new OSSUpdateStrategy();
-                strategy.Create(_configInfo);
-                await strategy.ExecuteAsync();
-                return this;
-            }
-
-            // Client-side OSS
-            var basePath = AppDomain.CurrentDomain.BaseDirectory;
-            var versionFileName = $"{_configInfo.MainAppName ?? _configInfo.AppName}_versions.json";
-            var versionsFilePath = Path.Combine(basePath, versionFileName);
-
-            DownloadOssFile(_configInfo.UpdateUrl, versionsFilePath);
-            if (!File.Exists(versionsFilePath)) return this;
-
-            var versions = StorageManager.GetJson<List<VersionOSS>>(versionsFilePath,
-                VersionOSSJsonContext.Default.ListVersionOSS);
-            if (versions == null || versions.Count == 0) return this;
-
-            versions = versions.OrderByDescending(x => x.PubTime).ToList();
-            var newVersion = versions.First();
-
-            if (!IsOssUpgrade(_configInfo.ClientVersion, newVersion.Version))
-            {
-                GeneralTracer.Info("LaunchOssAsync: no upgrade needed.");
-                return this;
-            }
-
-            // Use user-configured AppName, fall back to default updater name
-            var upgradeAppName = !string.IsNullOrWhiteSpace(_configInfo.AppName) && _configInfo.AppName != "Update.exe"
-                ? _configInfo.AppName
-                : "GeneralUpdate.Upgrade.exe";
-            var appPath = Path.Combine(basePath, upgradeAppName);
-            if (!File.Exists(appPath))
-                throw new Exception($"Upgrade application not found: {upgradeAppName}");
-
-            var ossConfig = new GlobalConfigInfoOSS
-            {
-                AppName = _configInfo.MainAppName ?? _configInfo.AppName,
-                CurrentVersion = _configInfo.ClientVersion,
-                VersionFileName = versionFileName,
-                Encoding = (_configInfo.Encoding?.CodePage ?? Encoding.UTF8.CodePage).ToString(),
-                Url = _configInfo.UpdateUrl
-            };
-
-            var serialized = JsonSerializer.Serialize(ossConfig,
-                GlobalConfigInfoOSSJsonContext.Default.GlobalConfigInfoOSS);
-            Environments.SetEnvironmentVariable("GlobalConfigInfoOSS", serialized);
-            Process.Start(appPath);
-            await GracefulExit.CurrentProcessAsync().ConfigureAwait(false);
-        }
-        catch (Exception ex)
-        {
-            GeneralTracer.Error("LaunchOssAsync failed.", ex);
-            EventManager.Instance.Dispatch(this, new ExceptionEventArgs(ex, ex.Message));
-        }
-        return this;
-    }
 
     // ════════════════════════════════════════════════════════════════
     // Configuration
@@ -373,26 +308,6 @@ private async Task CallSmallBowlHomeAsync(string processName)
         }
     }
 
-    private static void DownloadOssFile(string url, string path)
-    {
-        if (File.Exists(path))
-        {
-            File.SetAttributes(path, FileAttributes.Normal);
-            File.Delete(path);
-        }
-        using var webClient = new System.Net.WebClient();
-        webClient.DownloadFile(new Uri(url), path);
-    }
-
-    private static bool IsOssUpgrade(string clientVersion, string serverVersion)
-    {
-        if (string.IsNullOrWhiteSpace(clientVersion) || string.IsNullOrWhiteSpace(serverVersion))
-            return false;
-        return Version.TryParse(clientVersion, out var cv)
-            && Version.TryParse(serverVersion, out var sv)
-            && cv < sv;
-    }
-
     // ════════════════════════════════════════════════════════════════
     // Strategy & Events
     // ════════════════════════════════════════════════════════════════

src/c#/GeneralUpdate.Core/Configuration/AppType.cs

@@ -11,6 +11,9 @@ public enum AppType
     /// <summary>Upgrade application — applies downloaded update packages, starts main app.</summary>
     Upgrade = 2,
 
-    /// <summary>OSS (Object Storage Service) update mode — downloads from cloud storage.</summary>
-    OSS = 3
+    /// <summary>OSS client mode — checks version config, starts upgrade process.</summary>
+    OSSClient = 3,
+
+    /// <summary>OSS upgrade mode — downloads packages from OSS, deploys to client.</summary>
+    OSSUpgrade = 4
 }