CommandLine ICommand

ICommand.cs

using CommandLine;
using CommandLine.Text;
using System.Reflection;

/// <summary>
/// A CLI command of the application, like <i>clone</i> in <i>git clone</i>.
/// Corresponds to a verb in the CommandLineParser.
/// </summary>
/// <remarks>
/// Derived types are created by the CommandLineParser and their Run method is called when parsing was successful.
/// Using this interface makes it possible to automatically parse all verbs in the assembly without having to
/// define them individually by hand.
/// </remarks>
[UsedImplicitly(ImplicitUseTargetFlags.WithInheritors | ImplicitUseTargetFlags.Members)]
public interface ICommand
{
	public void Run();

	/// <summary>
	/// Run this in the program's entry point to parse the command line arguments and execute the appropriate command.
	/// </summary>
	/// <param name="args">
	/// The arguments passed in the main method.
	/// Do not use Environment.GetCommandLineArgs() because it includes the path to the executable.
	/// </param>
	public static void Parse(IEnumerable<string> args)
	{
		// Find all commands in the executing program.
		var commandTypes = Assembly.GetEntryAssembly()
			.GetTypes()
			.Where(t => typeof(ICommand).IsAssignableFrom(t) && !t.IsInterface && !t.IsAbstract)
			.ToArray();

		// Parse the arguments with customized help text.
		var parser = new Parser(with => with.HelpWriter = null);
		var parserResult = parser.ParseArguments(args, commandTypes);
		parserResult
			.WithParsed(command => ((ICommand)command).Run())
			.WithNotParsed(_ =>
			{
				var helpText = HelpText.AutoBuild(parserResult, h =>
				{
					h.AutoVersion = false; // hides --version
					h.Copyright = string.Empty;
					return HelpText.DefaultParsingErrorsHandler(parserResult, h);
				}, e => e);
				Console.WriteLine(helpText);
			});
	}
}