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CLArgs - A .NET Command-Line Parser

CLArgs is a Command-Line Parser or Command-Line Interpreter, which comes as a NuGet Package for .NET Console Applications.

Application.exe [Verbs] [Options] [Targets]

CLArgs turns your .NET Console Application into a modern command-line application with minimal coding effort while providing maximum flexibility and extensibility.

Documentation

Verbs [optional] represent different actions or commands your application can execute.

Options represent are the parameters you want to pass to your command.

Targets [optional] represent the items on which you want to perform an action, like a list of files.

Read the full documentation on GitPages.

Installation

Add the latest MSPro.CLArgs NuGet package to your .NET project .

image-20200810090003001

Examples

Data Converter

> DataConverterApp.exe XMLtoJSON --NullValueHandling=Default File1.xml Files2.xml

XMLToJSON would be the Verb - the Command that determines what should be done. NullValueHandlingis an option that is passed as a Parameter to the XMLtoJSON Command. And the two files are the Targets which would be passed to the Command.

Time converter

This application converts a given datetime (incl. time-zone) into UTC. The application does not support Verbs or Targets, it simply uses Options. Sample Code

> ConvertToUtc.exe --LocalDateTime='2020-08-01 08:10:00' --LocalTimeZone='Pacific Standard Time'

Code

void Main()
private static void Main(string[] args)
{
	// ...
	Commander.ExecuteCommand( args);
	// ...
}
The functionality -> the Command
// Implement your functionality 
// as a Command that takes Parameters (see below)

[Command("ConvertToUtc")]
class ConvertToUtcCommand : CommandBase<ConvertToUtcParameters>
{
    protected override void Execute(ConvertToUtcParameters ps)
    {
        // Time Zone checking - inline: string to TimeZone
        var localTimeZone=     TimeZoneInfo.FindSystemTimeZoneById(ps.LocalTimeZone);
        Console.WriteLine($"LocalDateTime={ps.LocalDateTime} "+
                          $"in TimeZone ''{ps.LocalTimeZone}''");
        
        DateTime utc = TimeZoneInfo.ConvertTimeToUtc( 
            ps.LocalDateTime, localTimeZone);
        
        Console.WriteLine($"is UTC: {utc}");
    }
}

Output

LocalDateTime=01.08.2020 08:10:00 in 'TimeZonePacific Standard' Time
is UTC: 01.08.2020 15:10:00
The Options -> the Parameters
//
// The parameters class. Command-line options will be turned into Parameters
//
class ConvertToUtcParameters
{
    [OptionDescriptor("LocalDateTime", required:true, 
             helpText:"A local date and time that should be converted into UTC.")]
    public DateTime LocalDateTime { get; set; }

    [OptionDescriptor("LocalTimeZone", required:true, 
             helpText:"Specify the LocalDateTime's time zone")]
    public string LocalTimeZone { get; set; }
}

Note: There are a couple of more options how to handle the LocalTimeZone option. In the example above it is simply defined as string. However, you could replace it with an Enum to enforce certain values, or you can even provide your own converter and/or validators.

All Samples on GitHub

Feature List

  • Simple but powerful to use
    • Probably only one single line of code in your app: Commander.ExecuteCommand( args);
  • Zero dependencies of the NuGet package
  • Any dotnet version
  • Unlimited number of Verbs
  • Plug-In concept: Automatic Command resolution based on Verbs
  • Different argument-sets for each Command
    • Sub-Classes (inheritance) for parameter objects

See Command-Runner for an extensible skeleton to use CLArgs.

  • Flexible argument validation and completion
  • Clean error-handling to report all errors instead of only the first one
    • When using a console application, It can be frustrating to see "Param1 is missing" and once you fixed it you get: "Param2 is missing".
    • CLArgs reports all errors in a single run.
  • Support for command and argument help-text
    • Help-Texts and argument definitions can be loaded from files, from Resources or they can be build-in by code or a combination of these.
    • This includes support for localized help-messages.
  • Support for custom property types and enums in your parameter classes
  • Support converting custom value converters
    • to convert any command-line string-value into any Type
  • Dynamic default values (not only static, like True, "abc")
    • Including depend default values, e. g. on other values
  • ...

Markus Schmidt (PRO), Munich (DE), 2020-07-10