readme.md

CommandLineParser.DependencyInjection

This is a simple wrapper around the amazing commandlineparser/commandline library which adds support for Microsoft's DI with help from Scrutor. This is done by allow the following interfaces to be implemented which DI will find and user for executing the commandlineparser.

Interface	Description
ICommandLineOptions	This is an empty interface that is used solely for DI to find options! Make a class with Options just like the CommandLineParser library instructs!
ICommandLineParser< TResult >	This is the DI Service you will use to access the Parser and execute the relevant DI Service for IExecuteCommandLineOptions/IExecuteCommandLineOptionsAsync. It has the ability to run both synchronously or asynchronously.
IExecuteCommandLineOptions<TCommandLineOptions, TResult>	Interface that implements Execute(options) synchronously with the Parser's Command Line Options.
IExecuteCommandLineOptionsAsync<TCommandLineOptions, TResult>	Interface that implements ExecuteAsync(options) asynchronously with the Parser's Command Line Options.
IExecuteParsingFailure	If no Options/Handler found, this is called synchronously with the executed arguments array and parser errors to handle the inability to handle the command line input arguments.
IExecuteParsingFailureAsync< TResult >	If no Options/Handler found, this is called asynchronously with the executed arguments array and parser errors to handle the inability to handle the command line input arguments.

Example

Here is an example of the QuickStart from commandlineparser/commandline implemented using DI. In this case though, we're writing to Microsoft's Logging ILogger that is getting injected using DI instead of writing directly to console!

using CommandLine;
using CommandLineParser.DependencyInjection.Interfaces;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
 
new ServiceCollection() // Create Service Collection
        .AddCommandLineParser(typeof(Options).Assembly) // Add CommandLineParser registrations to DI
        .AddLogging(c => c.AddConsole()) // Add Console Logging
    .BuildServiceProvider() // Build Service Provider
        .GetRequiredService<ICommandLineParser<int>>() // Get Parser Service
            .ParseArguments(args, -1) // Call Parser with Arguments (Options and ExecuteOptions will be loaded from DI as needed)
    ;
 
public class Options: ICommandLineOptions
{
    [Option('v', "verbose", Required = false, HelpText = "Set output to verbose messages.")]
    public bool Verbose { get; set; }
}
 
public class ExecuteOptions(ILogger<ExecuteOptions> log) : IExecuteCommandLineOptions<Options, int>
{
    #region Implementation of IExecuteCommandLineOptions<in Options,out int>
 
    /// <summary>
    /// Execute Command Synchronously.
    /// </summary>
    /// <param name="options">Command Line Options</param>
    /// <returns>Result</returns>
    public int Execute(Options options)
    {
        if (options.Verbose)
        {
            log.LogInformation($"Verbose output enabled. Current Arguments: -v {options.Verbose}");
            log.LogWarning("Quick Start Example! App is in Verbose mode!");
        }
        else
        {
            log.LogInformation($"Current Arguments: -v {options.Verbose}");
            log.LogInformation("Quick Start Example!");
        }
 
        return 0;
    }
 
    #endregion
}

Unit Tests

See the Test's project for example.

The Tests project has 3 folders:

• Options: These are the CommandLineOptions, exactly how the commandlineparser/commandline library defines them, with the ICommandLineOptions interface added for DI discovering. The only difference is that one is used for calling async instead of sync in tests.
• ExecuteAskOptions: These are both Sync and Async dummy implementations of services that handle the AskOptions as well as handle Parsing failures.
• Services: Dummy service that returns a string based on the arguments provided.