only actors can save me

Management/Services/Files/FileStorageManager.cs

@@ -1,14 +1,6 @@
 using LocalModels;
 using Management.Services;
 
-public interface IFileStorageManager
-{
-  Task SaveCourseAsync(LocalCourse course, LocalCourse? previouslyStoredCourse);
-  Task<IEnumerable<LocalCourse>> LoadSavedCourses();
-  Task<IEnumerable<LocalCourse>> LoadSavedMarkdownCourses();
-  IEnumerable<string> GetEmptyDirectories();
-}
-
 public class FileStorageManager : IFileStorageManager
 {
   private readonly MyLogger<FileStorageManager> logger;
@@ -44,13 +36,7 @@ public class FileStorageManager : IFileStorageManager
 
   public async Task<IEnumerable<LocalCourse>> LoadSavedCourses()
   {
-    return await LoadSavedMarkdownCourses();
-  }
-
-  public async Task<IEnumerable<LocalCourse>> LoadSavedMarkdownCourses()
-  {
-
-    return await _courseMarkdownLoader.LoadSavedMarkdownCourses();
+    return await _courseMarkdownLoader.LoadSavedCourses();
   }
 
   public IEnumerable<string> GetEmptyDirectories()

Management/Services/Files/FileStorageManagerCached.cs

@@ -0,0 +1,50 @@
+
+using System.Diagnostics.CodeAnalysis;
+using LocalModels;
+
+public class FileStorageManagerCached : IFileStorageManager
+{
+  private readonly FileStorageManager manager;
+
+  private readonly object cacheLock = new object();  // Lock object for synchronization
+
+
+  private DateTime? cacheTime { get; set; } = null;
+  private IEnumerable<LocalCourse>? cachedCourses { get; set; } = null;
+  private ILogger<FileStorageManagerCached> logger { get; }
+
+  private readonly int cacheSeconds = 2;
+  public FileStorageManagerCached(FileStorageManager manager, ILogger<FileStorageManagerCached> logger)
+  {
+    this.manager = manager;
+    this.logger = logger;
+  }
+  public IEnumerable<string> GetEmptyDirectories()
+  {
+    return manager.GetEmptyDirectories();
+  }
+
+  public async Task<IEnumerable<LocalCourse>> LoadSavedCourses()
+  {
+
+    var secondsFromLastLoad = (DateTime.Now - cacheTime)?.Seconds;
+
+    if (cachedCourses != null && secondsFromLastLoad < cacheSeconds)
+    {
+      logger.LogInformation("returning cached courses from file");
+      return cachedCourses;
+    }
+
+    cachedCourses = await manager.LoadSavedCourses();
+    cacheTime = DateTime.Now;
+    return cachedCourses;
+  }
+
+  public async Task SaveCourseAsync(LocalCourse course, LocalCourse? previouslyStoredCourse)
+  {
+    // race condition...
+    cacheTime = null;
+    cachedCourses = null;
+    await manager.SaveCourseAsync(course, previouslyStoredCourse);
+  }
+}

Management/Services/Files/IFileStorageManager.cs

@@ -0,0 +1,8 @@
+using LocalModels;
+
+public interface IFileStorageManager
+{
+  Task SaveCourseAsync(LocalCourse course, LocalCourse? previouslyStoredCourse);
+  Task<IEnumerable<LocalCourse>> LoadSavedCourses();
+  IEnumerable<string> GetEmptyDirectories();
+}

Management/Services/Files/LoadMarkdownCourse.cs

@@ -12,7 +12,7 @@ public class CourseMarkdownLoader
     _basePath = fileConfig.GetBasePath();
   }
 
-  public async Task<IEnumerable<LocalCourse>> LoadSavedMarkdownCourses()
+  public async Task<IEnumerable<LocalCourse>> LoadSavedCourses()
   {
     var courseDirectories = Directory.GetDirectories(_basePath);