(#494) Watch Chocolatey config file for changes

When Chocolatey CLI makes changes to the configuration file while
Chocolatey GUI is running, Chocolatey GUI should refresh the sources so
that they're accurate. This adds a FileSystemWatcher to monitor the
configuration file and update the GUI if there's updates to the file.

Source/ChocolateyGui.Common.Windows/Bootstrapper.cs

@@ -121,6 +121,7 @@ protected override async void OnStartup(object sender, StartupEventArgs e)
 
                 var packageService = Container.Resolve<IChocolateyService>();
                 var features = await packageService.GetFeatures();
+                var fileSystemWatcher = Container.Resolve<IConfigFileWatcher>();
 
                 var backgroundFeature = features.FirstOrDefault(feature => string.Equals(feature.Name, "useBackgroundService", StringComparison.OrdinalIgnoreCase));
                 var elevationProvider = Elevation.Instance;

Source/ChocolateyGui.Common.Windows/ChocolateyGui.Common.Windows.csproj

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
   <PropertyGroup>
@@ -229,6 +229,7 @@
     </Compile>
     <Compile Include="Controls\Dialogs\IClosableDialog.cs" />
     <Compile Include="Controls\Dialogs\IClosableChildWindow.cs" />
+    <Compile Include="Services\ConfigFileWatcher.cs" />
     <Compile Include="Services\DialogService.cs" />
     <Compile Include="Services\IDialogService.cs" />
     <Compile Include="Utilities\ChocolateyMessageBox.cs" />

Source/ChocolateyGui.Common.Windows/Services/ConfigFileWatcher.cs

@@ -0,0 +1,53 @@
+// --------------------------------------------------------------------------------------------------------------------
+// <copyright company="Chocolatey" file="ConfigFileWatcher.cs">
+//   Copyright 2017 - Present Chocolatey Software, LLC
+//   Copyright 2014 - 2017 Rob Reynolds, the maintainers of Chocolatey, and RealDimensions Software, LLC
+// </copyright>
+// --------------------------------------------------------------------------------------------------------------------
+
+using System.IO;
+using Caliburn.Micro;
+using chocolatey.infrastructure.app.configuration;
+using chocolatey.infrastructure.services;
+using ChocolateyGui.Common.Models.Messages;
+using ChocolateyGui.Common.Services;
+using IFileSystem = chocolatey.infrastructure.filesystem.IFileSystem;
+
+namespace ChocolateyGui.Common.Windows.Services
+{
+    public class ConfigFileWatcher : IConfigFileWatcher
+    {
+        private readonly IFileSystem _fileSystem;
+        private readonly IEventAggregator _eventAggregator;
+        private readonly FileSystemWatcher _fileSystemWatcher;
+        private readonly IXmlService _xmlService;
+        private readonly string _configFile = chocolatey.infrastructure.app.ApplicationParameters.GlobalConfigFileLocation;
+        private int _lastKnownConfigFileHash;
+
+        public ConfigFileWatcher(IFileSystem fileSystem, IEventAggregator eventAggregator, IXmlService xmlService)
+        {
+            _fileSystem = fileSystem;
+            _eventAggregator = eventAggregator;
+            _xmlService = xmlService;
+            _fileSystemWatcher = new FileSystemWatcher
+            {
+                Path = _fileSystem.get_directory_name(_configFile),
+                Filter = _fileSystem.get_file_name(_configFile),
+                NotifyFilter = NotifyFilters.LastWrite | NotifyFilters.FileName,
+            };
+            _fileSystemWatcher.Changed += ConfigFileChanged;
+            _fileSystemWatcher.EnableRaisingEvents = true;
+            _lastKnownConfigFileHash = _xmlService.deserialize<ConfigFileSettings>(_configFile).GetHashCode();
+        }
+
+        private void ConfigFileChanged(object sender, FileSystemEventArgs e)
+        {
+            var currentSettingsHash = _xmlService.deserialize<ConfigFileSettings>(_configFile).GetHashCode();
+            if (currentSettingsHash != _lastKnownConfigFileHash)
+            {
+                _eventAggregator.PublishOnUIThread(new SourcesUpdatedMessage());
+                _lastKnownConfigFileHash = currentSettingsHash;
+            }
+        }
+    }
+}

Source/ChocolateyGui.Common.Windows/Startup/ChocolateyGuiModule.cs

@@ -52,6 +52,7 @@ protected override void Load(ContainerBuilder builder)
             builder.RegisterType<DotNetFileSystem>().As<chocolatey.infrastructure.filesystem.IFileSystem>().SingleInstance();
             builder.RegisterType<PackageArgumentsService>().As<IPackageArgumentsService>().SingleInstance();
             builder.RegisterType<DefaultEncryptionUtility>().As<IEncryptionUtility>().SingleInstance();
+            builder.RegisterType<ConfigFileWatcher>().As<IConfigFileWatcher>().SingleInstance();
 
             // Register ViewModels
             builder.RegisterAssemblyTypes(viewModelAssembly)

Source/ChocolateyGui.Common/ChocolateyGui.Common.csproj

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
   <PropertyGroup>
@@ -185,6 +185,7 @@
     <Compile Include="Services\IAllowedCommandsService.cs" />
     <Compile Include="Services\IChocolateyGuiCacheService.cs" />
     <Compile Include="Services\IChocolateyService.cs" />
+    <Compile Include="Services\IConfigFileWatcher.cs" />
     <Compile Include="Services\IConfigService.cs" />
     <Compile Include="Services\IFileStorageService.cs" />
     <Compile Include="Services\IPersistenceService.cs" />

Source/ChocolateyGui.Common/Services/IConfigFileWatcher.cs

@@ -0,0 +1,13 @@
+// --------------------------------------------------------------------------------------------------------------------
+// <copyright company="Chocolatey" file="IConfigFileWatcher.cs">
+//   Copyright 2017 - Present Chocolatey Software, LLC
+//   Copyright 2014 - 2017 Rob Reynolds, the maintainers of Chocolatey, and RealDimensions Software, LLC
+// </copyright>
+// --------------------------------------------------------------------------------------------------------------------
+
+namespace ChocolateyGui.Common.Services
+{
+    public interface IConfigFileWatcher
+    {
+    }
+}