Index: TFP-WebServer/WebServer/src/FileCache/InvalidateCachesCmd.cs
===================================================================
--- TFP-WebServer/WebServer/src/FileCache/InvalidateCachesCmd.cs	(revision 439)
+++ TFP-WebServer/WebServer/src/FileCache/InvalidateCachesCmd.cs	(revision 487)
@@ -5,13 +5,13 @@
 	[UsedImplicitly]
 	public class InvalidateCachesCmd : ConsoleCmdAbstract {
-		protected override string[] getCommands () {
+		public override string[] getCommands () {
 			return new[] {"invalidatecaches"};
 		}
 
-		protected override string getDescription () {
+		public override string getDescription () {
 			return "Invalidate contents of web file caches";
 		}
 
-		protected override string getHelp () {
+		public override string getHelp () {
 			return "TODO";
 		}
Index: TFP-WebServer/WebServer/src/FileCache/SimpleCache.cs
===================================================================
--- TFP-WebServer/WebServer/src/FileCache/SimpleCache.cs	(revision 439)
+++ TFP-WebServer/WebServer/src/FileCache/SimpleCache.cs	(revision 487)
@@ -11,6 +11,6 @@
 			try {
 				lock (fileCache) {
-					if (fileCache.ContainsKey (_filename)) {
-						return fileCache [_filename];
+					if (fileCache.TryGetValue(_filename, out byte[] content)) {
+						return content;
 					}
 
@@ -19,7 +19,8 @@
 					}
 
-					fileCache.Add (_filename, File.ReadAllBytes (_filename));
+					byte[] newContent = File.ReadAllBytes (_filename);
+					fileCache.Add (_filename, newContent);
 
-					return fileCache [_filename];
+					return newContent;
 				}
 			} catch (Exception e) {