Add an overload of UseTypeActivator(...) that takes a list of added command types

CliFx.Demo/Program.cs

@@ -1,25 +1,21 @@
 using CliFx;
-using CliFx.Demo.Commands;
 using CliFx.Demo.Domain;
 using Microsoft.Extensions.DependencyInjection;
 
-// We use Microsoft.Extensions.DependencyInjection for injecting dependencies in commands
-var services = new ServiceCollection();
-
-// Register services
-services.AddSingleton<LibraryProvider>();
-
-// Register commands
-services.AddTransient<BookCommand>();
-services.AddTransient<BookAddCommand>();
-services.AddTransient<BookRemoveCommand>();
-services.AddTransient<BookListCommand>();
-
-var serviceProvider = services.BuildServiceProvider();
-
 return await new CliApplicationBuilder()
     .SetDescription("Demo application showcasing CliFx features.")
     .AddCommandsFromThisAssembly()
-    .UseTypeActivator(serviceProvider.GetRequiredService)
+    .UseTypeActivator(commandTypes =>
+    {
+        // We use Microsoft.Extensions.DependencyInjection for injecting dependencies in commands
+        var services = new ServiceCollection();
+        services.AddSingleton<LibraryProvider>();
+
+        // Register all commands as transient services
+        foreach (var commandType in commandTypes)
+            services.AddTransient(commandType);
+
+        return services.BuildServiceProvider();
+    })
     .Build()
     .RunAsync();

CliFx.Tests/TypeActivationSpecs.cs

@@ -156,14 +156,23 @@ public class TypeActivationSpecs : SpecsBase
             """
         );
 
-        var serviceProvider = new ServiceCollection()
-            .AddSingleton(commandType, Activator.CreateInstance(commandType, "Hello world")!)
-            .BuildServiceProvider();
-
         var application = new CliApplicationBuilder()
             .AddCommand(commandType)
             .UseConsole(FakeConsole)
-            .UseTypeActivator(serviceProvider)
+            .UseTypeActivator(commandTypes =>
+            {
+                var services = new ServiceCollection();
+
+                foreach (var serviceType in commandTypes)
+                {
+                    services.AddSingleton(
+                        serviceType,
+                        Activator.CreateInstance(serviceType, "Hello world")!
+                    );
+                }
+
+                return services.BuildServiceProvider();
+            })
             .Build();
 
         // Act

CliFx/CliApplicationBuilder.cs

@@ -33,7 +33,6 @@ public partial class CliApplicationBuilder
     public CliApplicationBuilder AddCommand(Type commandType)
     {
         _commandTypes.Add(commandType);
-
         return this;
     }
 
@@ -112,7 +111,7 @@ public partial class CliApplicationBuilder
     }
 
     /// <summary>
-    /// Sets application title, which is shown in the help text.
+    /// Sets the application title, which is shown in the help text.
     /// </summary>
     /// <remarks>
     /// By default, application title is inferred from the assembly name.
@@ -124,11 +123,10 @@ public partial class CliApplicationBuilder
     }
 
     /// <summary>
-    /// Sets application executable name, which is shown in the help text.
+    /// Sets the application executable name, which is shown in the help text.
     /// </summary>
     /// <remarks>
     /// By default, application executable name is inferred from the assembly file name.
-    /// The file name is also prefixed with `dotnet` if it's a DLL file.
     /// </remarks>
     public CliApplicationBuilder SetExecutableName(string executableName)
     {
@@ -137,8 +135,7 @@ public partial class CliApplicationBuilder
     }
 
     /// <summary>
-    /// Sets application version, which is shown in the help text or
+    /// Sets the application version, which is shown in the help text or when the user specifies the version option.
-    /// when the user specifies the version option.
     /// </summary>
     /// <remarks>
     /// By default, application version is inferred from the assembly version.
@@ -150,7 +147,7 @@ public partial class CliApplicationBuilder
     }
 
     /// <summary>
-    /// Sets application description, which is shown in the help text.
+    /// Sets the application description, which is shown in the help text.
     /// </summary>
     public CliApplicationBuilder SetDescription(string? description)
     {
@@ -177,10 +174,10 @@ public partial class CliApplicationBuilder
     }
 
     /// <summary>
-    /// Configures the application to use the specified function for activating types.
+    /// Configures the application to use the specified delegate for activating types.
     /// </summary>
-    public CliApplicationBuilder UseTypeActivator(Func<Type, object> typeActivator) =>
+    public CliApplicationBuilder UseTypeActivator(Func<Type, object> createInstance) =>
-        UseTypeActivator(new DelegateTypeActivator(typeActivator));
+        UseTypeActivator(new DelegateTypeActivator(createInstance));
 
     /// <summary>
     /// Configures the application to use the specified service provider for activating types.
@@ -188,6 +185,14 @@ public partial class CliApplicationBuilder
     public CliApplicationBuilder UseTypeActivator(IServiceProvider serviceProvider) =>
         UseTypeActivator(serviceProvider.GetService);
 
+    /// <summary>
+    /// Configures the application to use the specified service provider for activating types.
+    /// This method takes a delegate that receives the list of all added command types, so that you can
+    /// easily register them with the service provider.
+    /// </summary>
+    public CliApplicationBuilder UseTypeActivator(Func<IReadOnlyList<Type>, IServiceProvider> getServiceProvider) =>
+        UseTypeActivator(getServiceProvider(_commandTypes.ToArray()));
+
     /// <summary>
     /// Creates a configured instance of <see cref="CliApplication" />.
     /// </summary>
@@ -221,45 +226,56 @@ public partial class CliApplicationBuilder
     {
         var entryAssemblyName = EnvironmentEx.EntryAssembly?.GetName().Name;
         if (string.IsNullOrWhiteSpace(entryAssemblyName))
-            return "App";
+        {
+            throw new InvalidOperationException(
+                "Failed to infer the default application title. " +
+                $"Please specify it explicitly using {nameof(SetTitle)}()."
+            );
+        }
 
         return entryAssemblyName;
     }
 
     private static string GetDefaultExecutableName()
     {
-        var entryAssemblyLocation = EnvironmentEx.EntryAssembly?.Location;
+        var entryAssemblyFilePath = EnvironmentEx.EntryAssembly?.Location;
-        if (string.IsNullOrWhiteSpace(entryAssemblyLocation))
+        var processFilePath = EnvironmentEx.ProcessPath;
-            return "app";
 
-        // If the application was launched via matching EXE apphost, use that as the executable name
+        if (string.IsNullOrWhiteSpace(entryAssemblyFilePath) || string.IsNullOrWhiteSpace(processFilePath))
-        var isLaunchedViaAppHost = string.Equals(
+        {
-            EnvironmentEx.ProcessPath,
+            throw new InvalidOperationException(
-            Path.ChangeExtension(entryAssemblyLocation, ".exe"),
+                "Failed to infer the default application executable name. " +
-            StringComparison.OrdinalIgnoreCase
+                $"Please specify it explicitly using {nameof(SetExecutableName)}()."
-        );
+            );
+        }
 
-        if (isLaunchedViaAppHost)
+        // If the process path matches the entry assembly path, it's a legacy .NET Framework app
-            return Path.GetFileNameWithoutExtension(entryAssemblyLocation);
+        // or a self-contained .NET Core app.
+        if (PathEx.AreEqual(entryAssemblyFilePath, processFilePath))
+            return Path.GetFileNameWithoutExtension(entryAssemblyFilePath);
 
-        // Otherwise, use the entry assembly as the executable name.
+        // If the process path has the same name and parent directory as the entry assembly path,
-        // Prefix it with `dotnet` if it's a DLL file.
+        // but different extension, it's a framework-dependent .NET Core app launched through the apphost.
-        var isDll = string.Equals(
+        if (PathEx.AreEqual(Path.ChangeExtension(entryAssemblyFilePath, ".exe"), processFilePath) ||
-            Path.GetExtension(entryAssemblyLocation),
+            PathEx.AreEqual(Path.ChangeExtension(entryAssemblyFilePath, ""), processFilePath))
-            ".dll",
+        {
-            StringComparison.OrdinalIgnoreCase
+            return Path.GetFileNameWithoutExtension(entryAssemblyFilePath);
-        );
+        }
 
-        return isDll
+        // Otherwise, it's a framework-dependent .NET Core app launched through the .NET CLI
-            ? "dotnet " + Path.GetFileName(entryAssemblyLocation)
+        return "dotnet " + Path.GetFileName(entryAssemblyFilePath);
-            : Path.GetFileNameWithoutExtension(entryAssemblyLocation);
     }
 
     private static string GetDefaultVersionText()
     {
         var entryAssemblyVersion = EnvironmentEx.EntryAssembly?.GetName().Version;
         if (entryAssemblyVersion is null)
-            return "v1.0";
+        {
+            throw new InvalidOperationException(
+                "Failed to infer the default application version. " +
+                $"Please specify it explicitly using {nameof(SetVersion)}()."
+            );
+        }
 
         return "v" + entryAssemblyVersion.ToSemanticString();
     }

CliFx/Infrastructure/DelegateTypeActivator.cs

@@ -4,22 +4,22 @@ using CliFx.Exceptions;
 namespace CliFx.Infrastructure;
 
 /// <summary>
-/// Implementation of <see cref="ITypeActivator" /> that instantiates an object
+/// Implementation of <see cref="ITypeActivator" /> that instantiates an object by using a predefined delegate.
-/// by using a predefined function.
 /// </summary>
 public class DelegateTypeActivator : ITypeActivator
 {
-    private readonly Func<Type, object> _func;
+    private readonly Func<Type, object> _createInstance;
 
     /// <summary>
     /// Initializes an instance of <see cref="DelegateTypeActivator" />.
     /// </summary>
-    public DelegateTypeActivator(Func<Type, object> func) => _func = func;
+    public DelegateTypeActivator(Func<Type, object> createInstance) =>
+        _createInstance = createInstance;
 
     /// <inheritdoc />
     public object CreateInstance(Type type)
     {
-        var instance = _func(type);
+        var instance = _createInstance(type);
 
         if (instance is null)
         {

CliFx/Utils/PathEx.cs

@@ -0,0 +1,22 @@
+using System;
+using System.IO;
+using System.Runtime.InteropServices;
+
+namespace CliFx.Utils;
+
+internal static class PathEx
+{
+    private static StringComparer EqualityComparer { get; } =
+        RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
+            ? StringComparer.OrdinalIgnoreCase
+            : StringComparer.Ordinal;
+
+    public static bool AreEqual(string path1, string path2)
+    {
+        static string Normalize(string path) => Path
+            .GetFullPath(path)
+            .Trim(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar);
+
+        return EqualityComparer.Equals(Normalize(path1), Normalize(path2));
+    }
+}

Readme.md

@@ -531,24 +531,24 @@ The following example shows how to configure your application to use [`Microsoft
 ```csharp
 public static class Program
 {
-    public static async Task<int> Main()
+    public static async Task<int> Main() =>
-    {
+        await new CliApplicationBuilder()
-        var services = new ServiceCollection();
-
-        // Register services
-        services.AddSingleton<MyService>();
-
-        // Register commands
-        services.AddTransient<MyCommand>();
-
-        var serviceProvider = services.BuildServiceProvider();
-
-        return await new CliApplicationBuilder()
             .AddCommandsFromThisAssembly()
-            .UseTypeActivator(serviceProvider)
+            .UseTypeActivator(commandTypes =>
+            {
+                var services = new ServiceCollection();
+
+                // Register services
+                services.AddSingleton<MyService>();
+
+                // Register commands
+                foreach (var commandType in commandTypes)
+                    services.AddTransient(commandType);
+
+                return services.BuildServiceProvider();
+            })
             .Build()
             .RunAsync();
-    }
 }
 ```