Split IApplicationBuilder extensions into separate class, and ensure app.AddReact (registering depenencies in DI container) is called before app.UseReact (registering React middleware)

Author: Daniel15

src/React.AspNet/HtmlHelperExtensions.cs

@@ -7,6 +7,9 @@
  *  of patent rights can be found in the PATENTS file in the same directory.
  */
 
+using React.Exceptions;
+using React.TinyIoC;
+
 #if LEGACYASPNET
 using System.Web;
 using System.Web.Mvc;
@@ -33,8 +36,25 @@ public static class HtmlHelperExtensions
 		/// </summary>
 		private static IReactEnvironment Environment
 		{
-			// TODO: Figure out if this can be injected
-			get { return global::React.AssemblyRegistration.Container.Resolve<IReactEnvironment>(); }
+			get
+			{
+				try
+				{
+					return global::React.AssemblyRegistration.Container.Resolve<IReactEnvironment>();
+				}
+				catch (TinyIoCResolutionException ex)
+				{
+					throw new ReactNotInitialisedException(
+#if LEGACYASPNET
+						"ReactJS.NET has not been initialised correctly.",
+#else
+						"ReactJS.NET has not been initialised correctly. Please ensure you have " +
+						"called app.AddReact() and app.UseReact() in your Startup.cs file.",
+#endif
+						ex
+					);
+				}
+			}
 		}
 
 		/// <summary>

src/React.AspNet/HttpContextLifetimeProvider.cs

@@ -13,6 +13,7 @@
 using Microsoft.AspNet.Hosting;
 using Microsoft.AspNet.Http;
 using Microsoft.Framework.DependencyInjection;
+using React.Exceptions;
 using React.TinyIoC;
 
 namespace React.AspNet
@@ -52,8 +53,21 @@ public HttpContextLifetimeProvider(IServiceProvider appServiceProvider)
 		/// <summary>
 		/// Gets the current per-request registrations for the current request.
 		/// </summary>
-		private PerRequestRegistrations Registrations => 
-			HttpContext.RequestServices.GetRequiredService<PerRequestRegistrations>();
+		private PerRequestRegistrations Registrations
+		{
+			get
+			{
+				var registrations = HttpContext.RequestServices.GetService<PerRequestRegistrations>();
+				if (registrations == null)
+				{
+					throw new ReactNotInitialisedException(
+						"ReactJS.NET has not been initialised correctly. Please ensure you have " +
+						"called app.AddReact() and app.UseReact() in your Startup.cs file."
+					);
+				}
+				return registrations;
+			}
+		}
 
 		/// <summary>
 		/// Gets the value of this item in the dependency injection container.

src/React.AspNet/ReactBuilderExtensions.cs

@@ -0,0 +1,86 @@
+/*
+ *  Copyright (c) 2015, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant 
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+using System;
+using Microsoft.AspNet.Builder;
+using Microsoft.AspNet.Hosting;
+using Microsoft.Framework.DependencyInjection;
+using Microsoft.Framework.Runtime;
+using React.Exceptions;
+using React.TinyIoC;
+
+namespace React.AspNet
+{
+	/// <summary>
+	/// Handles registering ReactJS.NET middleware in an ASP.NET <see cref="IApplicationBuilder"/>.
+	/// </summary>
+    public static class ReactBuilderExtensions
+    {
+		/// <summary>
+		/// Initialises ReactJS.NET for this application
+		/// </summary>
+		/// <param name="app">ASP.NET application builder</param>
+		/// <param name="configure">ReactJS.NET configuration</param>
+		/// <param name="fileOptions">Options to use for serving JSX files</param>
+		/// <returns>The application builder (for chaining)</returns>
+		public static IApplicationBuilder UseReact(
+			this IApplicationBuilder app,
+			Action<IReactSiteConfiguration> configure,
+			JsxFileOptions fileOptions = null
+		)
+		{
+			EnsureServicesRegistered(app);
+
+			// Register IApplicationEnvironment in our dependency injection container
+			// Ideally this would be in AddReact(IServiceCollection) but we can't 
+			// access IApplicationEnvironment there.
+			React.AssemblyRegistration.Container.Register(app.ApplicationServices.GetRequiredService<IApplicationEnvironment>());
+			React.AssemblyRegistration.Container.Register(app.ApplicationServices.GetRequiredService<IHostingEnvironment>());
+
+			Initializer.Initialize(registerOptions => AsPerRequestSingleton(app.ApplicationServices, registerOptions));
+			configure(ReactSiteConfiguration.Configuration);
+
+			// Allow serving of .jsx files
+			app.UseMiddleware<JsxFileMiddleware>(fileOptions ?? new JsxFileOptions());
+
+			return app;
+		}
+
+		/// <summary>
+		/// Registers a class such that every ASP.NET web request has a single instance of it.
+		/// </summary>
+		/// <param name="appServiceProvider">ASP.NET service provider</param>
+		/// <param name="registerOptions">Registration options</param>
+		/// <returns>Registration options (for chaining)</returns>
+		private static TinyIoCContainer.RegisterOptions AsPerRequestSingleton(
+			IServiceProvider appServiceProvider,
+			TinyIoCContainer.RegisterOptions registerOptions
+		)
+		{
+			return TinyIoCContainer.RegisterOptions.ToCustomLifetimeManager(
+				registerOptions,
+				new HttpContextLifetimeProvider(appServiceProvider),
+				"per request singleton"
+			);
+		}
+
+		/// <summary>
+		/// Ensures React services have been registered in the ASP.NET dependency injection container.
+		/// </summary>
+		/// <param name="app">ASP.NET application builder</param>
+		private static void EnsureServicesRegistered(IApplicationBuilder app)
+		{
+			var registrations = app.ApplicationServices.GetService<HttpContextLifetimeProvider.PerRequestRegistrations>();
+			if (registrations == null)
+			{
+				throw new ReactNotInitialisedException("Please call app.AddReact() before app.UseReact().");
+			}
+		}
+	}
+}

src/React.AspNet/ReactServiceCollectionExtensions.cs

@@ -7,14 +7,13 @@
  *  of patent rights can be found in the PATENTS file in the same directory.
  */
 
-using System;
-using Microsoft.AspNet.Builder;
 using Microsoft.Framework.DependencyInjection;
-using Microsoft.Framework.Runtime;
-using React.TinyIoC;
 
 namespace React.AspNet
 {
+	/// <summary>
+	/// Handles registering ReactJS.NET services in the ASP.NET <see cref="IServiceCollection"/>.
+	/// </summary>
 	public static class ReactServiceCollectionExtensions
 	{
 		/// <summary>
@@ -27,50 +26,5 @@ public static IServiceCollection AddReact(this IServiceCollection services)
 			services.AddScoped<HttpContextLifetimeProvider.PerRequestRegistrations>();
 			return services;
 		}
-
-		/// <summary>
-		/// Initialises ReactJS.NET for this application
-		/// </summary>
-		/// <param name="app">ASP.NET application builder</param>
-		/// <param name="configure">ReactJS.NET configuration</param>
-		/// <param name="fileOptions">Options to use for serving JSX files</param>
-		/// <returns>The application builder (for chaining)</returns>
-		public static IApplicationBuilder UseReact(
-			this IApplicationBuilder app, 
-			Action<IReactSiteConfiguration> configure,
-			JsxFileOptions fileOptions = null
-		)
-		{
-			// Register IApplicationEnvironment in our dependency injection container
-			// Ideally this would be in AddReact(IServiceCollection) but we can't 
-			// access IApplicationEnvironment there.
-			React.AssemblyRegistration.Container.Register(app.ApplicationServices.GetRequiredService<IApplicationEnvironment>());
-
-			Initializer.Initialize(registerOptions => AsPerRequestSingleton(app.ApplicationServices, registerOptions));
-			configure(ReactSiteConfiguration.Configuration);
-
-			// Allow serving of .jsx files
-			app.UseMiddleware<JsxFileMiddleware>(fileOptions ?? new JsxFileOptions());
-
-			return app;
-		}
-
-		/// <summary>
-		/// Registers a class such that every ASP.NET web request has a single instance of it.
-		/// </summary>
-		/// <param name="appServiceProvider">ASP.NET service provider</param>
-		/// <param name="registerOptions">Registration options</param>
-		/// <returns>Registration options (for chaining)</returns>
-		private static TinyIoCContainer.RegisterOptions AsPerRequestSingleton(
-			IServiceProvider appServiceProvider, 
-			TinyIoCContainer.RegisterOptions registerOptions
-		)
-		{
-			return TinyIoCContainer.RegisterOptions.ToCustomLifetimeManager(
-				registerOptions,
-				new HttpContextLifetimeProvider(appServiceProvider),
-				"per request singleton"
-			);
-		}
 	}
 }

src/React.Core/Exceptions/ReactNotInitialisedException.cs

@@ -0,0 +1,41 @@
+/*
+ *  Copyright (c) 2015, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant 
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+using System;
+using System.Runtime.Serialization;
+
+namespace React.Exceptions
+{
+	/// <summary>
+	/// Thrown when React has not been initialised correctly.
+	/// </summary>
+	[Serializable]
+	public class ReactNotInitialisedException : ReactException
+	{
+		/// <summary>
+		/// Initializes a new instance of the <see cref="ReactNotInitialisedException"/> class.
+		/// </summary>
+		/// <param name="message">The message that describes the error.</param>
+		public ReactNotInitialisedException(string message) : base(message) { }
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="ReactNotInitialisedException"/> class.
+		/// </summary>
+		/// <param name="message">The error message that explains the reason for the exception.</param>
+		/// <param name="innerException">The exception that is the cause of the current exception, or a null reference (Nothing in Visual Basic) if no inner exception is specified.</param>
+		public ReactNotInitialisedException(string message, Exception innerException)
+			: base(message, innerException) { }
+
+		/// <summary>
+		/// Used by deserialization
+		/// </summary>
+		protected ReactNotInitialisedException(SerializationInfo info, StreamingContext context)
+			: base(info, context) { }
+	}
+}

src/React.Core/React.Core.csproj

@@ -89,6 +89,7 @@
       <Link>Properties\SharedAssemblyVersionInfo.cs</Link>
     </Compile>
     <Compile Include="AssemblyRegistration.cs" />
+    <Compile Include="Exceptions\ReactNotInitialisedException.cs" />
     <Compile Include="JavaScriptEngineUtils.cs" />
     <Compile Include="VroomJsEngine.cs" />
     <Compile Include="Exceptions\ClearScriptV8InitialisationException.cs" />

src/React.Sample.Mvc6/project.json

@@ -14,6 +14,7 @@
         "Microsoft.Framework.Logging.Console": "1.0.0.0-beta3",
         "Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.0.0-beta1",
         "React.AspNet": "",
+        "React.Core": "",
         "JavaScriptEngineSwitcher.V8": "1.2.4.0",
         "JavaScriptEngineSwitcher.Msie": "1.2.4.0"
     },

src/wrap/React/project.json

@@ -0,0 +1,21 @@
+{
+  "version": "1.4.0-*",
+  "frameworks": {
+    "net40": {
+      "wrappedProject": "../../React.Core/React.Core.csproj",
+      "bin": {
+        "assembly": "../../React.Core/obj/{configuration}/React.dll",
+        "pdb": "../../React.Core/obj/{configuration}/React.pdb"
+      },
+      "dependencies": {
+        "JavaScriptEngineSwitcher.Core": "1.2.4",
+        "JavaScriptEngineSwitcher.V8": "1.2.4",
+        "JSPool": "0.2.0",
+        "Newtonsoft.Json": "5.0.4",
+        "VroomJs": "1.0.0-*",
+        "JavaScriptEngineSwitcher.Msie": "1.2.4",
+        "MsieJavaScriptEngine": "1.5.1"
+      }
+    }
+  }
+}