Cake build: access original command line arguments string?

Question

While trying to squeeze Mono.Options into my Cake script, I noticed I wasn't entirely sure how to give it the original arguments string from the command line call that launched the Cake script in the first place. Mono.Options Parse method takes what would be a typical console app's string[] args parameter, so I need to feed it something it can work with.

I know I can query the context for specific arguments with ArgumentAlias calls, but is there any way to access the entire original string calling string?

Answer 1

Cake scripts are essentially just a regular .NET Process to you can access it through System.Environment.GetCommandLineArgs()

Example PoC

Quick n dirty example of one way you could use Mono.Options with Cake below

#addin nuget:?package=Mono.Options&version=5.3.0.1
using Mono.Options;

public static class MyOptions
{
    public static bool ShouldShowHelp { get; set; } = false;
    public static List<string> Names { get; set; } = new List<string>();
    public static int Repeat { get; set; } = 1;
}

var p = new OptionSet {
            { "name=",    "the name of someone to greet.",                          n => MyOptions.Names.Add (n) },
            { "repeat=",  "the number of times to MyOptions.Repeat the greeting.",  (int r) => MyOptions.Repeat = r },
            // help is reserved cake command so using options instead
            { "options",     "show this message and exit",                             h => MyOptions.ShouldShowHelp = h != null },
        };

try {
    p.Parse (
        System.Environment.GetCommandLineArgs()
        // Skip Cake.exe and potential cake file.
        // i.e. "cake --name="Mattias""
        //  or "cake build.cake --name="Mattias""
        .SkipWhile(arg=>arg.EndsWith(".exe", StringComparison.OrdinalIgnoreCase)||arg.EndsWith(".cake", StringComparison.OrdinalIgnoreCase))
        .ToArray()
    );
}
catch (OptionException e) {
    Information("Options Sample: ");
    Information (e.Message);
    Information ("--options' for more information.");
    return;
}

if (MyOptions.ShouldShowHelp || MyOptions.Names.Count == 0)
{
    var sw = new StringWriter();
    p.WriteOptionDescriptions (sw);
    Information(
        "Usage: [OPTIONS]"
        );
    Information(sw);
    return;
}

string message = "Hello {0}!";

foreach (string name in MyOptions.Names) {
    for (int i = 0; i < MyOptions.Repeat; ++i)
        Information (message, name);
}

Example output

cake .\Mono.Options.cake will output help as no names specified

cake .\Mono.Options.cake --options will output "help"

cake .\Mono.Options.cake --name=Mattias will greet me

cake .\Mono.Options.cake --name="Mattias" --repeat=5 will greet me 5 times

cake .\Mono.Options.cake --name="Mattias" --repeat=sdss will fail and report because repeat not a number