From 1653e56b98451020a8e34ec335c84ef7b2f58626 Mon Sep 17 00:00:00 2001
From: Eugene Bekker <ebekker@users.noreply.github.com>
Date: Sat, 10 Feb 2018 19:37:36 -0500
Subject: [PATCH] Adding ability to qualify the entry point of the main
 assembly

---
 samples/StandaloneApp/Program.cs              | 10 +++++++-
 samples/StandaloneApp/StandaloneApp.csproj    |  1 +
 .../src/Boot.ts                               | 14 ++++++-----
 .../src/Platform/Mono/MonoPlatform.ts         | 17 +++++++++++--
 .../src/Platform/Platform.ts                  |  2 +-
 .../Core/FileSystem/ClientFileProvider.cs     | 12 +++++++++-
 .../Core/FileSystem/IndexHtmlFileProvider.cs  | 24 +++++++++++++++----
 .../IndexHtmlFileProviderTest.cs              | 10 ++++----
 .../ReferencedAssemblyFileProviderTest.cs     |  2 +-
 .../Tests/StandaloneAppTest.cs                |  4 ++--
 10 files changed, 72 insertions(+), 24 deletions(-)

diff --git a/samples/StandaloneApp/Program.cs b/samples/StandaloneApp/Program.cs
index 1244342d11..c5a4bbba2d 100644
--- a/samples/StandaloneApp/Program.cs
+++ b/samples/StandaloneApp/Program.cs
@@ -5,7 +5,15 @@ using Microsoft.AspNetCore.Blazor.Browser.Rendering;
 
 namespace StandaloneApp
 {
-    public class Program
+    public class ProgramX
+    {
+        public static void Main(string[] args)
+        {
+            new BrowserRenderer().AddComponent<Home>("app");
+        }
+    }
+
+    public class ProgramY
     {
         public static void Main(string[] args)
         {
diff --git a/samples/StandaloneApp/StandaloneApp.csproj b/samples/StandaloneApp/StandaloneApp.csproj
index 558911261e..2c16743b73 100644
--- a/samples/StandaloneApp/StandaloneApp.csproj
+++ b/samples/StandaloneApp/StandaloneApp.csproj
@@ -6,6 +6,7 @@
     <!-- Local alternative to <RunArguments>blazor serve</RunArguments> -->
     <RunCommand>dotnet</RunCommand>
     <RunArguments>run --project ../../src/Microsoft.AspNetCore.Blazor.DevHost serve</RunArguments>
+    <StartupObject>StandaloneApp.ProgramY</StartupObject>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Boot.ts b/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Boot.ts
index d1e59ffd78..6a77d6a3dc 100644
--- a/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Boot.ts
+++ b/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Boot.ts
@@ -7,11 +7,13 @@ async function boot() {
   // Read startup config from the <script> element that's importing this file
   const allScriptElems = document.getElementsByTagName('script');
   const thisScriptElem = document.currentScript || allScriptElems[allScriptElems.length - 1];
-  const entryPoint = thisScriptElem.getAttribute('main');
-  if (!entryPoint) {
-    throw new Error('Missing "main" attribute on Blazor Config script tag.');
+  const entryPointDll = thisScriptElem.getAttribute('main');
+  if (!entryPointDll) {
+    throw new Error('Missing "main" attribute on Blazor script tag.');
   }
-  const entryPointAssemblyName = getAssemblyNameFromUrl(entryPoint);
+  // TODO:  should method be a required, non-empty field or just an optional *hint*?
+  const entryPointMethod = thisScriptElem.getAttribute('entry-point');
+  const entryPointAssemblyName = getAssemblyNameFromUrl(entryPointDll);
   const referenceAssembliesCommaSeparated = thisScriptElem.getAttribute('references') || '';
   const referenceAssemblies = referenceAssembliesCommaSeparated
     .split(',')
@@ -19,7 +21,7 @@ async function boot() {
     .filter(s => !!s);
 
   // Determine the URLs of the assemblies we want to load
-  const loadAssemblyUrls = [entryPoint]
+  const loadAssemblyUrls = [entryPointDll]
     .concat(referenceAssemblies)
     .map(filename => `/_framework/_bin/${filename}`);
 
@@ -30,7 +32,7 @@ async function boot() {
   }
 
   // Start up the application
-  platform.callEntryPoint(entryPointAssemblyName, []);
+  platform.callEntryPoint(entryPointAssemblyName, entryPointMethod, []);
 }
 
 boot();
diff --git a/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Platform/Mono/MonoPlatform.ts b/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Platform/Mono/MonoPlatform.ts
index 0ced33cd42..6fa6ccdc7d 100644
--- a/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Platform/Mono/MonoPlatform.ts
+++ b/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Platform/Mono/MonoPlatform.ts
@@ -45,11 +45,24 @@ export const monoPlatform: Platform = {
     return methodHandle;
   },
 
-  callEntryPoint: function callEntryPoint(assemblyName: string, args: System_Object[]): void {
+  callEntryPoint: function callEntryPoint(assemblyName: string, methodName: string | null, args: System_Object[]): void {
     // TODO: There should be a proper way of running whatever counts as the entrypoint without
     // having to specify what method it is, but I haven't found it. The code here assumes
     // that the entry point is "<assemblyname>.Program.Main" (i.e., namespace == assembly name).
-    const entryPointMethod = monoPlatform.findMethod(assemblyName, assemblyName, 'Program', 'Main');
+    if (!methodName)
+        methodName = assemblyName + ".Program::Main";
+
+    var classAndMethod = methodName.split("::");
+    if (classAndMethod.length != 2)
+        throw new Error("malformed entry point method name; could not resolve class name and method name");
+
+    methodName = classAndMethod[1];
+    const nsAndClass = classAndMethod[0];
+    const lastDot = nsAndClass.lastIndexOf(".");
+    // It's possible the entry point method has no namespace
+    const namespace = lastDot > -1 ? classAndMethod[0].substring(0, lastDot) : "";
+    const className = lastDot > -1 ? classAndMethod[0].substring(lastDot + 1) : classAndMethod[0];
+    const entryPointMethod = monoPlatform.findMethod(assemblyName, namespace, className, methodName);
     monoPlatform.callMethod(entryPointMethod, null, args);
   },
 
diff --git a/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Platform/Platform.ts b/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Platform/Platform.ts
index a4cc52be51..38cad75f7c 100644
--- a/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Platform/Platform.ts
+++ b/src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Platform/Platform.ts
@@ -1,7 +1,7 @@
 export interface Platform {
   start(loadAssemblyUrls: string[]): Promise<void>;
 
-  callEntryPoint(assemblyName: string, args: System_Object[]);
+  callEntryPoint(assemblyName: string, assemblyMethod: string | null, args: System_Object[]);
   findMethod(assemblyName: string, namespace: string, className: string, methodName: string): MethodHandle;
   callMethod(method: MethodHandle, target: System_Object | null, args: System_Object[]): System_Object;
 
diff --git a/src/Microsoft.AspNetCore.Blazor.Build/Core/FileSystem/ClientFileProvider.cs b/src/Microsoft.AspNetCore.Blazor.Build/Core/FileSystem/ClientFileProvider.cs
index 7e8e9993b5..2f7d4a7117 100644
--- a/src/Microsoft.AspNetCore.Blazor.Build/Core/FileSystem/ClientFileProvider.cs
+++ b/src/Microsoft.AspNetCore.Blazor.Build/Core/FileSystem/ClientFileProvider.cs
@@ -3,6 +3,7 @@
 
 using Microsoft.AspNetCore.Blazor.Internal.Common.FileProviders;
 using Microsoft.Extensions.FileProviders;
+using Mono.Cecil;
 using System.Collections.Generic;
 using System.IO;
 
@@ -50,8 +51,17 @@ namespace Microsoft.AspNetCore.Blazor.Build.Core.FileSystem
                 {
                     var template = File.ReadAllText(path);
                     var assemblyName = Path.GetFileNameWithoutExtension(assemblyPath);
+                    var assemblyEntryPoint = string.Empty;
                     var binFiles = frameworkFileProvider.GetDirectoryContents("/_bin");
-                    result = new IndexHtmlFileProvider(template, assemblyName, binFiles);
+
+                    using (var asmDef = AssemblyDefinition.ReadAssembly(assemblyPath))
+                    {
+                        var ep = asmDef.EntryPoint;
+                        if (ep != null)
+                            assemblyEntryPoint = $"{ep.DeclaringType.FullName}::{ep.Name}";
+                    }
+
+                    result = new IndexHtmlFileProvider(template, assemblyName, assemblyEntryPoint, binFiles);
                     return true;
                 }
             }
diff --git a/src/Microsoft.AspNetCore.Blazor.Build/Core/FileSystem/IndexHtmlFileProvider.cs b/src/Microsoft.AspNetCore.Blazor.Build/Core/FileSystem/IndexHtmlFileProvider.cs
index 9312b923e3..7f9fb9aada 100644
--- a/src/Microsoft.AspNetCore.Blazor.Build/Core/FileSystem/IndexHtmlFileProvider.cs
+++ b/src/Microsoft.AspNetCore.Blazor.Build/Core/FileSystem/IndexHtmlFileProvider.cs
@@ -15,16 +15,23 @@ namespace Microsoft.AspNetCore.Blazor.Build.Core.FileSystem
 {
     internal class IndexHtmlFileProvider : InMemoryFileProvider
     {
-        public IndexHtmlFileProvider(string htmlTemplate, string assemblyName, IEnumerable<IFileInfo> binFiles)
-            : base(ComputeContents(htmlTemplate, assemblyName, binFiles))
+        public IndexHtmlFileProvider(
+            string htmlTemplate,
+            string assemblyName,
+            string assemblyEntryPoint,
+            IEnumerable<IFileInfo> binFiles) : base(ComputeContents(htmlTemplate, assemblyName, assemblyEntryPoint, binFiles))
         {
         }
 
-        private static IEnumerable<(string, byte[])> ComputeContents(string htmlTemplate, string assemblyName, IEnumerable<IFileInfo> binFiles)
+        private static IEnumerable<(string, byte[])> ComputeContents(
+            string htmlTemplate,
+            string assemblyName,
+            string assemblyEntryPoint,
+            IEnumerable<IFileInfo> binFiles)
         {
             if (htmlTemplate != null)
             {
-                var html = GetIndexHtmlContents(htmlTemplate, assemblyName, binFiles);
+                var html = GetIndexHtmlContents(htmlTemplate, assemblyName, assemblyEntryPoint, binFiles);
                 var htmlBytes = Encoding.UTF8.GetBytes(html);
                 yield return ("/index.html", htmlBytes);
             }
@@ -48,7 +55,11 @@ namespace Microsoft.AspNetCore.Blazor.Build.Core.FileSystem
         /// responsible for completing the Blazor boot process.
         /// </para>
         /// </remarks>
-        private static string GetIndexHtmlContents(string htmlTemplate, string assemblyName, IEnumerable<IFileInfo> binFiles)
+        private static string GetIndexHtmlContents(
+            string htmlTemplate,
+            string assemblyName,
+            string assemblyEntryPoint,
+            IEnumerable<IFileInfo> binFiles)
         {
             var resultBuilder = new StringBuilder();
 
@@ -86,6 +97,7 @@ namespace Microsoft.AspNetCore.Blazor.Build.Core.FileSystem
                                 AppendScriptTagWithBootConfig(
                                     resultBuilder,
                                     assemblyName,
+                                    assemblyEntryPoint,
                                     binFiles,
                                     tag.Attributes);
 
@@ -123,6 +135,7 @@ namespace Microsoft.AspNetCore.Blazor.Build.Core.FileSystem
         private static void AppendScriptTagWithBootConfig(
             StringBuilder resultBuilder,
             string assemblyName,
+            string assemblyEntryPoint,
             IEnumerable<IFileInfo> binFiles,
             List<KeyValuePair<string, string>> attributes)
         {
@@ -136,6 +149,7 @@ namespace Microsoft.AspNetCore.Blazor.Build.Core.FileSystem
             attributesDict.Remove("type");
             attributesDict["src"] = "/_framework/blazor.js";
             attributesDict["main"] = assemblyNameWithExtension;
+            attributesDict["entry-point"] = assemblyEntryPoint;
             attributesDict["references"] = referencesAttribute;
 
             resultBuilder.Append("<script");
diff --git a/test/Microsoft.AspNetCore.Blazor.Build.Test/IndexHtmlFileProviderTest.cs b/test/Microsoft.AspNetCore.Blazor.Build.Test/IndexHtmlFileProviderTest.cs
index 221f844217..bfd0f8c55d 100644
--- a/test/Microsoft.AspNetCore.Blazor.Build.Test/IndexHtmlFileProviderTest.cs
+++ b/test/Microsoft.AspNetCore.Blazor.Build.Test/IndexHtmlFileProviderTest.cs
@@ -18,7 +18,7 @@ namespace Microsoft.AspNetCore.Blazor.Server.Test
         {
             // Arrange
             var instance = new IndexHtmlFileProvider(
-                null, "fakeassembly", Enumerable.Empty<IFileInfo>());
+                null, "fakeassembly", null, Enumerable.Empty<IFileInfo>());
 
             // Act
             var file = instance.GetFileInfo("/index.html");
@@ -33,7 +33,7 @@ namespace Microsoft.AspNetCore.Blazor.Server.Test
             // Arrange
             var htmlTemplate = "test";
             var instance = new IndexHtmlFileProvider(
-                htmlTemplate, "fakeassembly", Enumerable.Empty<IFileInfo>());
+                htmlTemplate, "fakeassembly", null, Enumerable.Empty<IFileInfo>());
 
             // Act
             var file = instance.GetFileInfo("/index.html");
@@ -52,7 +52,7 @@ namespace Microsoft.AspNetCore.Blazor.Server.Test
             // Arrange
             var htmlTemplate = "test";
             var instance = new IndexHtmlFileProvider(
-                htmlTemplate, "fakeassembly", Enumerable.Empty<IFileInfo>());
+                htmlTemplate, "fakeassembly", null, Enumerable.Empty<IFileInfo>());
 
             // Act
             var directory = instance.GetDirectoryContents(string.Empty);
@@ -86,7 +86,7 @@ namespace Microsoft.AspNetCore.Blazor.Server.Test
                 new TestFileInfo("MyApp.ClassLib.dll"),
             };
             var instance = new IndexHtmlFileProvider(
-                htmlTemplate, "MyApp.Entrypoint", dependencies);
+                htmlTemplate, "MyApp.Entrypoint", null, dependencies);
 
             // Act
             var file = instance.GetFileInfo("/index.html");
@@ -120,7 +120,7 @@ namespace Microsoft.AspNetCore.Blazor.Server.Test
                 new TestFileInfo("MyApp.ClassLib.dll"),
             };
             var instance = new IndexHtmlFileProvider(
-                htmlTemplate, "MyApp.Entrypoint", dependencies);
+                htmlTemplate, "MyApp.Entrypoint", null, dependencies);
 
             // Act
             var file = instance.GetFileInfo("/index.html");
diff --git a/test/Microsoft.AspNetCore.Blazor.Build.Test/ReferencedAssemblyFileProviderTest.cs b/test/Microsoft.AspNetCore.Blazor.Build.Test/ReferencedAssemblyFileProviderTest.cs
index 30e153b7e0..9c77e36c12 100644
--- a/test/Microsoft.AspNetCore.Blazor.Build.Test/ReferencedAssemblyFileProviderTest.cs
+++ b/test/Microsoft.AspNetCore.Blazor.Build.Test/ReferencedAssemblyFileProviderTest.cs
@@ -46,7 +46,7 @@ namespace Microsoft.AspNetCore.Blazor.Server.Test
         public void FindsReferencedAssemblyGraphRealistic()
         {
             // Arrange
-            var standaloneAppAssembly = typeof(StandaloneApp.Program).Assembly;
+            var standaloneAppAssembly = typeof(StandaloneApp.ProgramY).Assembly;
             var provider = new ReferencedAssemblyFileProvider(
                 standaloneAppAssembly.GetName().Name,
                 new ReferencedAssemblyResolver(
diff --git a/test/Microsoft.AspNetCore.Blazor.E2ETest/Tests/StandaloneAppTest.cs b/test/Microsoft.AspNetCore.Blazor.E2ETest/Tests/StandaloneAppTest.cs
index bfcac18d6e..c9cd8cbb04 100644
--- a/test/Microsoft.AspNetCore.Blazor.E2ETest/Tests/StandaloneAppTest.cs
+++ b/test/Microsoft.AspNetCore.Blazor.E2ETest/Tests/StandaloneAppTest.cs
@@ -11,9 +11,9 @@ using Xunit;
 namespace Microsoft.AspNetCore.Blazor.E2ETest.Tests
 {
     public class StandaloneAppTest
-        : ServerTestBase<DevHostServerFixture<StandaloneApp.Program>>
+        : ServerTestBase<DevHostServerFixture<StandaloneApp.ProgramY>>
     {
-        public StandaloneAppTest(BrowserFixture browserFixture, DevHostServerFixture<StandaloneApp.Program> serverFixture)
+        public StandaloneAppTest(BrowserFixture browserFixture, DevHostServerFixture<StandaloneApp.ProgramY> serverFixture)
             : base(browserFixture, serverFixture)
         {
             Navigate("/", noReload: true);