Add open browser options to docfx-serve command

src/Microsoft.DocAsCode.App/RunServe.cs

@@ -1,17 +1,21 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Diagnostics;
+using System.Runtime.InteropServices;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.DocAsCode.Common;
 using Microsoft.Extensions.FileProviders;
+using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
+using Microsoft.DocAsCode.Plugins;
 
 namespace Microsoft.DocAsCode;
 
 internal static class RunServe
 {
-    public static void Exec(string folder, string host, int? port)
+    public static void Exec(string folder, string host, int? port, bool openBrowser, string openBrowserRelativePath)
     {
         if (string.IsNullOrEmpty(folder))
             folder = Directory.GetCurrentDirectory();
@@ -43,11 +47,104 @@ public static void Exec(string folder, string host, int? port)
             Console.WriteLine($"Serving \"{folder}\" on {url}. Press Ctrl+C to shut down.");
             using var app = builder.Build();
             app.UseFileServer(fileServerOptions);
-            app.Run();
+
+            if (openBrowser)
+            {
+                string relativePath = openBrowserRelativePath;
+                var launchUrl = string.IsNullOrEmpty(relativePath)
+                    ? url
+                    : Path.Combine(url, ResolveOutputHtmlRelativePath(folder, relativePath));
+
+                // Start web server.
+                app.Start();
+
+                // Launch browser process.
+
+                Console.WriteLine($"Launching browser with url: {url}.");
+                using var process = LaunchBrowser(launchUrl);
+
+                // Wait until server exited.
+                app.WaitForShutdown();
+
+                // process object is disposed. (Note:Launched process remain running.after dispose)
+            }
+            else
+            {
+                app.Run();
+            }
         }
         catch (System.Reflection.TargetInvocationException)
         {
             Logger.LogError($"Error serving \"{folder}\" on {url}, check if the port is already being in use.");
         }
     }
+
+    /// <summary>
+    /// Resolve output HTML file path by `manifest.json` file.
+    /// </summary>
+    private static string ResolveOutputHtmlRelativePath(string folder, string relativePath)
+    {
+        var manifestPath = Path.GetFullPath(Path.Combine(folder, "manifest.json"));
+        if (!File.Exists(manifestPath))
+            return string.Empty;
+
+        try
+        {
+            Manifest manifest = JsonUtility.Deserialize<Manifest>(manifestPath);
+
+            // Try to find output html file (html->html)
+            OutputFileInfo outputFileInfo = manifest.FindOutputFileInfo(relativePath);
+            if (outputFileInfo != null)
+                return outputFileInfo.RelativePath;
+
+            // Try to resolve output HTML file. (md->html)
+            relativePath = relativePath.Replace('\\', '/'); // Normalize path.
+            var manifestFile = manifest.Files
+                                       .Where(x => FilePathComparer.OSPlatformSensitiveRelativePathComparer.Equals(x.SourceRelativePath, relativePath))
+                                       .FirstOrDefault(x => x.OutputFiles.TryGetValue(".html", out outputFileInfo));
+
+            if (outputFileInfo != null)
+                return outputFileInfo.RelativePath;
+        }
+        catch (Exception)
+        {
+            throw; // Unexpected exception occurred.(e.g. Failed to deserialize Manifest)
+        }
+
+        // Failed to resolve output HTML file.
+        Logger.LogError($"Failed to resolve output HTML file path. sourceRelativePath: {relativePath}");
+        return string.Empty;
+    }
+
+    private static Process LaunchBrowser(string url)
+    {
+        try
+        {
+            // Windows
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                return Process.Start("cmd", new[] { "/C", "start", url });
+            }
+
+            // Linux
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+            {
+                return Process.Start("xdg-open", url);
+            }
+
+            // OSX
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            {
+                return Process.Start("open", url);
+            }
+
+            Logger.LogError($"Could not launch the browser process. Unknown OS platform: {RuntimeInformation.OSDescription}");
+        }
+        catch (Exception ex)
+        {
+            Logger.LogError($"Could not launch the browser process, with error - {ex.Message}");
+        }
+
+        return null;
+    }
 }

src/docfx/Models/BuildCommand.cs

@@ -19,7 +19,7 @@ public override int Execute(CommandContext context, BuildCommandOptions settings
             var serveDirectory = RunBuild.Exec(config.Item, new(), baseDirectory, settings.OutputFolder);
 
             if (settings.Serve)
-                RunServe.Exec(serveDirectory, settings.Host, settings.Port);
+                RunServe.Exec(serveDirectory, settings.Host, settings.Port, settings.OpenBrowser, settings.OpenBrowserRelativePath);
         });
     }
 

src/docfx/Models/BuildCommandOptions.cs

@@ -48,6 +48,14 @@ internal class BuildCommandOptions : LogOptions
     [CommandOption("-p|--port")]
     public int? Port { get; set; }
 
+    [Description("Open a web browser when the hosted website starts.")]
+    [CommandOption("--open-browser")]
+    public bool OpenBrowser { get; set; }
+
+    [Description("Specify the relative path to open.")]
+    [CommandOption("--open-browser-relative-path")]
+    public string OpenBrowserRelativePath { get; set; }
+
     [Description("Run in debug mode. With debug mode, raw model and view model will be exported automatically when it encounters error when applying templates. If not specified, it is false.")]
     [CommandOption("--debug")]
     public bool EnableDebugMode { get; set; }

src/docfx/Models/DefaultCommand.cs

@@ -52,7 +52,7 @@ public override int Execute(CommandContext context, Options options)
 
             if (options.Serve && serveDirectory is not null)
             {
-                RunServe.Exec(serveDirectory, options.Host, options.Port);
+                RunServe.Exec(serveDirectory, options.Host, options.Port, options.OpenBrowser, options.OpenBrowserRelativePath);
             }
         });
     }

src/docfx/Models/ServeCommand.cs

@@ -23,10 +23,18 @@ internal class Settings : CommandSettings
         [Description("Specify the port of the hosted website")]
         [CommandOption("-p|--port")]
         public int? Port { get; set; }
+
+        [Description("Open a web browser when the hosted website starts.")]
+        [CommandOption("--open-browser")]
+        public bool OpenBrowser { get; set; }
+
+        [Description("Specify the relative path to open.")]
+        [CommandOption("--open-browser-relative-path")]
+        public string OpenBrowserRelativePath { get; set; }
     }
 
     public override int Execute([NotNull] CommandContext context, [NotNull] Settings options)
     {
-        return CommandHelper.Run(() => RunServe.Exec(options.Folder, options.Host, options.Port));
+        return CommandHelper.Run(() => RunServe.Exec(options.Folder, options.Host, options.Port, options.OpenBrowser, options.OpenBrowserRelativePath));
     }
 }