Net Core - Add SelfHost class to CefSharp.Core

Allows for quick self hosting of the BrowserSubprocess

Issue #3197

Author: amaitland

CefSharp.BrowserSubprocess.Core/BrowserSubprocessExecutable.h

@@ -28,6 +28,25 @@ namespace CefSharp
 
             }
 
+            /// <summary>
+            /// This function should be called from the application entry point function (typically Program.Main)
+            /// to execute a secondary process e.g. gpu, plugin, renderer, utility
+            /// This overload is specifically used for .Net Core. For hosting your own BrowserSubProcess
+            /// it's preferable to use the Main method provided by this class.
+            /// - Obtains the command line args via a call to Environment::GetCommandLineArgs
+            /// - Calls CefEnableHighDPISupport before any other processing
+            /// </summary>
+            /// <returns>
+            /// If called for the browser process (identified by no "type" command-line value) it will return immediately
+            /// with a value of -1. If called for a recognized secondary process it will block until the process should exit
+            /// and then return the process exit code.
+            /// </returns
+            static int MainNetCoreSelfHost(array<String^>^ args)
+            {
+                auto subProcess = gcnew BrowserSubprocessExecutable();
+                return subProcess->Main(args, nullptr);
+            }
+
             /// <summary>
             /// This function should be called from the application entry point function (typically Program.Main)
             /// to execute a secondary process e.g. gpu, plugin, renderer, utility

CefSharp.Core/BrowserSubprocess/SelfHost.cpp

@@ -0,0 +1,46 @@
+// Copyright © 2020 The CefSharp Authors. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
+
+#include "Stdafx.h"
+#include "SelfHost.h"
+
+using namespace System;
+using namespace System::IO;
+using namespace System::Runtime::Loader;
+using namespace CefSharp;
+
+namespace CefSharp
+{
+    namespace BrowserSubprocess
+    {
+        int SelfHost::MainNetCore(array<String^>^ args)
+        {
+            auto type = CommandLineArgsParser::GetArgumentValue(args, CefSharpArguments::SubProcessTypeArgument);
+
+            if (String::IsNullOrEmpty(type))
+            {
+                //If --type param missing from command line CEF/Chromium assums
+                //this is the main process (as all subprocesses must have a type param).
+                //Return -1 to indicate this behaviour.
+                return -1;
+            }
+
+            auto browserSubprocessDllPath = Path::Combine(Path::GetDirectoryName(SelfHost::typeid->Assembly->Location), "CefSharp.BrowserSubprocess.Core.dll");
+            auto browserSubprocessDll = AssemblyLoadContext::Default->LoadFromAssemblyPath(browserSubprocessDllPath);
+            auto browserSubprocessExecutableType = browserSubprocessDll->GetType("CefSharp.BrowserSubprocess.BrowserSubprocessExecutable");
+            auto browserSubprocessExecutable = Activator::CreateInstance(browserSubprocessExecutableType);
+
+            auto mainMethod = browserSubprocessExecutableType->GetMethod("MainNetCoreSelfHost", System::Reflection::BindingFlags::Static | System::Reflection::BindingFlags::Public);
+            auto argCount = mainMethod->GetParameters();
+
+            auto methodArgs = gcnew array<Object^>(1);
+            methodArgs[0] = args;
+
+            auto exitCode = mainMethod->Invoke(nullptr, methodArgs);
+
+            return (int)exitCode;
+        }
+
+    }
+}

CefSharp.Core/BrowserSubprocess/SelfHost.h

@@ -0,0 +1,39 @@
+// Copyright © 2020 The CefSharp Authors. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
+
+#pragma once
+
+#include "Stdafx.h"
+
+namespace CefSharp
+{
+    namespace BrowserSubprocess
+    {
+        /// <summary>
+        /// SelfHost can be used to self host the BrowserSubProcess in your
+        /// existing application (preferred approach for .Net Core).
+        /// </summary>
+        public ref class SelfHost
+        {
+        public:
+            /// <summary>
+            /// This function should be called from the application entry point function (typically Program.Main)
+            /// to execute a secondary process e.g. gpu, plugin, renderer, utility
+            /// This overload is specifically used for .Net Core. For hosting your own BrowserSubProcess
+            /// it's preferable to use the Main method provided by this class.
+            /// - Pass in command line args
+            /// - To support High DPI Displays you should call  Cef.EnableHighDPISupport before any other processing
+            /// or add the relevant entries to your app.manifest
+            /// </summary>
+            /// <param name="args">command line args</param>
+            /// <returns>
+            /// If called for the browser process (identified by no "type" command-line value) it will return immediately
+            /// with a value of -1. If called for a recognized secondary process it will block until the process should exit
+            /// and then return the process exit code.
+            /// </returns
+            static int MainNetCore(array<String^>^ args);
+            
+        };
+    }
+}

CefSharp.Core/CefSharp.Core.netcore.vcxproj

@@ -246,6 +246,7 @@
     <ClCompile Include="RequestContext.cpp" />
     <ClCompile Include="Internals\CefResourceHandlerAdapter.cpp" />
     <ClCompile Include="RequestContextBuilder.cpp" />
+    <ClCompile Include="BrowserSubprocess\SelfHost.cpp" />
     <ClCompile Include="Stdafx.cpp">
       <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">Create</PrecompiledHeader>
       <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">Create</PrecompiledHeader>
@@ -305,6 +306,7 @@
     <ClInclude Include="Request.h" />
     <ClInclude Include="RequestContextBuilder.h" />
     <ClInclude Include="resource.h" />
+    <ClInclude Include="BrowserSubprocess\SelfHost.h" />
     <ClInclude Include="UrlRequest.h" />
     <ClInclude Include="WindowInfo.h" />
     <ClInclude Include="Internals\CefCompletionCallbackAdapter.h" />

CefSharp.Core/CefSharp.Core.netcore.vcxproj.filters

@@ -86,6 +86,9 @@
     <ClCompile Include="RequestContextBuilder.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="BrowserSubprocess\SelfHost.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="vcclr_local.h">
@@ -334,6 +337,9 @@
     <ClInclude Include="RequestContextBuilder.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="BrowserSubprocess\SelfHost.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="Internals\CefFrameWrapper.h">

CefSharp.WinForms.Example/Program.cs

@@ -17,15 +17,15 @@ public class Program
         [STAThread]
         public static int Main(string[] args)
         {
-            const bool simpleSubProcess = false;
+            const bool selfHostSubProcess = true;
 
             Cef.EnableHighDPISupport();
 
             //NOTE: Using a simple sub processes uses your existing application executable to spawn instances of the sub process.
             //Features like JSB, EvaluateScriptAsync, custom schemes require the CefSharp.BrowserSubprocess to function
-            if (simpleSubProcess)
+            if (selfHostSubProcess)
             {
-                var exitCode = Cef.ExecuteProcess();
+                var exitCode = CefSharp.BrowserSubprocess.SelfHost.MainNetCore(args);
 
                 if (exitCode >= 0)
                 {