Improve response time for first time users

On the first time installation of Orchard, the user gets to the setup screen, which
will take a while to finish (user entering data and the setup process itself).
We use this opportunity to start a background task to "pre-compile" all the known
views in the app folder, so that the application is more reponsive when the user
hits the homepage and admin screens for the first time.

--HG--
branch : dev

src/Orchard.Web/Modules/Orchard.Setup/Controllers/SetupController.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Web.Mvc;
+using Orchard.Environment;
 using Orchard.FileSystems.AppData;
 using Orchard.Setup.Services;
 using Orchard.Setup.ViewModels;
@@ -11,11 +12,13 @@ namespace Orchard.Setup.Controllers {
     [ValidateInput(false), Themed]
     public class SetupController : Controller {
         private readonly IAppDataFolder _appDataFolder;
+        private readonly IViewsBackgroundCompilation _viewsBackgroundCompilation;
         private readonly INotifier _notifier;
         private readonly ISetupService _setupService;
 
-        public SetupController(INotifier notifier, ISetupService setupService, IAppDataFolder appDataFolder) {
+        public SetupController(INotifier notifier, ISetupService setupService, IAppDataFolder appDataFolder, IViewsBackgroundCompilation viewsBackgroundCompilation) {
             _appDataFolder = appDataFolder;
+            _viewsBackgroundCompilation = viewsBackgroundCompilation;
             _notifier = notifier;
             _setupService = setupService;
             T = NullLocalizer.Instance;
@@ -37,6 +40,17 @@ namespace Orchard.Setup.Controllers {
 
         public ActionResult Index() {
             var initialSettings = _setupService.Prime();
+
+            // On the first time installation of Orchard, the user gets to the setup screen, which
+            // will take a while to finish (user inputting data and the setup process itself).
+            // We use this opportunity to start a background task to "pre-compile" all the known
+            // views in the app folder, so that the application is more reponsive when the user
+            // hits the homepage and admin screens for the first time.
+            if (StringComparer.OrdinalIgnoreCase.Equals(initialSettings.Name, "Default")) {
+                _viewsBackgroundCompilation.Start();
+            }
+
+            //
             return IndexViewResult(new SetupViewModel { AdminUsername = "admin", DatabaseIsPreconfigured = !string.IsNullOrEmpty(initialSettings.DataProvider)});
         }
 
@@ -75,6 +89,11 @@ namespace Orchard.Setup.Controllers {
 
                 _setupService.Setup(setupContext);
 
+                // First time installation if finally done. Tell the background views compilation
+                // process to stop, so that it doesn't interfere with the user (asp.net compilation
+                // uses a "single lock" mechanism for compiling views).
+                _viewsBackgroundCompilation.Stop();
+
                 // redirect to the welcome page.
                 return Redirect("~/");
             }

src/Orchard/Environment/OrchardStarter.cs

@@ -48,6 +48,7 @@ namespace Orchard.Environment {
             builder.RegisterType<DefaultProjectFileParser>().As<IProjectFileParser>().SingleInstance();
             builder.RegisterType<DefaultAssemblyLoader>().As<IAssemblyLoader>().SingleInstance();
             builder.RegisterType<HttpContextAccessor>().As<IHttpContextAccessor>().SingleInstance();
+            builder.RegisterType<ViewsBackgroundCompilation>().As<IViewsBackgroundCompilation>().SingleInstance();
 
             RegisterVolatileProvider<WebSiteFolder, IWebSiteFolder>(builder);
             RegisterVolatileProvider<AppDataFolder, IAppDataFolder>(builder);

src/Orchard/Environment/ViewsBackgroundCompilation.cs

@@ -0,0 +1,155 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Timers;
+using System.Web.Compilation;
+using Orchard.FileSystems.VirtualPath;
+using Orchard.Logging;
+
+namespace Orchard.Environment {
+    public interface IViewsBackgroundCompilation {
+        void Start();
+        void Stop();
+    }
+
+    public class ViewsBackgroundCompilation : IViewsBackgroundCompilation {
+        private readonly IVirtualPathProvider _virtualPathProvider;
+        private volatile bool _stopping;
+
+        public ViewsBackgroundCompilation(IVirtualPathProvider virtualPathProvider) {
+            _virtualPathProvider = virtualPathProvider;
+
+            Logger = NullLogger.Instance;
+        }
+
+        public ILogger Logger { get; set; }
+
+        public void Start() {
+            _stopping = false;
+            var timer = new Timer();
+            timer.Elapsed += CompileViews;
+            timer.Interval = TimeSpan.FromMilliseconds(100).TotalMilliseconds;
+            timer.AutoReset = false;
+            timer.Start();
+        }
+
+        public void Stop() {
+            _stopping = true;
+        }
+
+        public class CompilationContext {
+            public IEnumerable<string> DirectoriesToBrowse { get; set; }
+            public IEnumerable<string> FileExtensionsToCompile { get; set; }
+            public HashSet<string> ProcessedDirectories { get; set; }
+        }
+
+        private void CompileViews(object sender, ElapsedEventArgs elapsedEventArgs) {
+            Logger.Information("Starting background compilation of views");
+            ((Timer)sender).Stop();
+
+            // Hard-coded context based on current orchard profile
+            var context = new CompilationContext {
+                // Put most frequently used directories first in the list
+                DirectoriesToBrowse = new[] {
+                    // Setup
+                    "~/Modules/Orchard.Setup/Views",
+                    "~/Themes/SafeMode/Views",
+
+                    // Homepage
+                    "~/Themes/TheThemeMachine/Views",
+                    "~/Core/Common/Views",
+                    "~/Core/Contents/Views",
+                    "~/Core/Routable/Views",
+                    "~/Core/Settings/Views",
+                    "~/Core/Shapes/Views",
+                    "~/Core/Feeds/Views",
+                    "~/Modules/Orchard.Tags/Views",
+                    "~/Modules/Orchard.Widgets/Views",
+
+                    // Dashboard
+                    "~/Core/Dashboard/Views",
+                    "~/Themes/TheAdmin/Views",
+
+                    // "Edit" homepage
+                    "~/Modules/TinyMce/Views",
+
+                    // Various other admin pages
+                    "~/Modules/Orchard.Modules/Views",
+                    "~/Modules/Orchard.Users/Views",
+                    "~/Modules/Orchard.Media/Views",
+                    "~/Modules/Orchard.Comments/Views",
+
+                    // Leave these at end (as a best effort)
+                    "~/Core", "~/Modules", "~/Themes"
+                },
+                FileExtensionsToCompile = new[] { ".cshtml", ".acsx", ".aspx" },
+                ProcessedDirectories = new HashSet<string>(StringComparer.OrdinalIgnoreCase)
+            };
+
+            var directories = context
+                .DirectoriesToBrowse
+                .SelectMany(folder => GetViewDirectories(folder, context.FileExtensionsToCompile));
+
+            foreach (var viewDirectory in directories) {
+                if (_stopping) {
+                    if (Logger.IsEnabled(LogLevel.Information)) {
+                        var leftOvers = directories.Except(context.ProcessedDirectories).ToList();
+                        Logger.Information("Background compilation stopped before all directories were processed ({0} directories left)", leftOvers.Count);
+                        foreach (var directory in leftOvers) {
+                            Logger.Information("Directory not processed: '{0}'", directory);
+                        }
+                    }
+                    break;
+                }
+
+                CompileDirectory(context, viewDirectory);
+            }
+            Logger.Information("Ending background compilation of views");
+        }
+
+        private void CompileDirectory(CompilationContext context, string viewDirectory) {
+            // Prevent processing of the same directories multiple times (sligh performance optimization,
+            // as the build manager second call to compile a view is essentially a "no-op".
+            if (context.ProcessedDirectories.Contains(viewDirectory))
+                return;
+            context.ProcessedDirectories.Add(viewDirectory);
+
+            var stopwatch = new Stopwatch();
+            stopwatch.Start();
+            try {
+
+                var firstFile = _virtualPathProvider
+                    .ListFiles(viewDirectory)
+                    .Where(f => context.FileExtensionsToCompile.Any(e => f.EndsWith(e, StringComparison.OrdinalIgnoreCase)))
+                    .FirstOrDefault();
+
+                if (firstFile != null)
+                    BuildManager.GetCompiledAssembly(firstFile);
+            }
+            catch(Exception e) {
+                // Some views might not compile, this is ok and harmless in this
+                // context of pre-compiling views.
+                Logger.Information(e, "Compilation of directory '{0}' skipped", viewDirectory);
+            }
+            stopwatch.Stop();
+            Logger.Information("Directory '{0}' compiled in {1} msec", viewDirectory, stopwatch.ElapsedMilliseconds);
+        }
+
+        private IEnumerable<string> GetViewDirectories(string directory, IEnumerable<string> extensions) {
+            var result = new List<string>();
+            GetViewDirectories(_virtualPathProvider, directory, extensions, result);
+            return result;
+        }
+
+        private void GetViewDirectories(IVirtualPathProvider vpp, string directory, IEnumerable<string> extensions, ICollection<string> files) {
+            if (vpp.ListFiles(directory).Where(f => extensions.Any(e => f.EndsWith(e, StringComparison.OrdinalIgnoreCase))).Any()) {
+                files.Add(directory);
+            }
+
+            foreach (var childDirectory in vpp.ListDirectories(directory).OrderBy(d => d, StringComparer.OrdinalIgnoreCase)) {
+                GetViewDirectories(vpp, childDirectory, extensions, files);
+            }
+        }
+    }
+}

src/Orchard/Orchard.Framework.csproj

@@ -159,6 +159,7 @@
     <Compile Include="Environment\Extensions\Loaders\RawThemeExtensionLoader.cs" />
     <Compile Include="Environment\Features\FeatureManager.cs" />
     <Compile Include="Environment\IAssemblyLoader.cs" />
+    <Compile Include="Environment\ViewsBackgroundCompilation.cs" />
     <Compile Include="Environment\WorkContextImplementation.cs" />
     <Compile Include="Environment\WorkContextModule.cs" />
     <Compile Include="Environment\WorkContextProperty.cs" />