Mahamudra.Guard

A simple package with guard extensions that uses the Railway Oriented Programming, a powerful Functional Programming pattern.

Usage

#region isnull private static Result<T, Error> IsNull<T>(T input, string parameter) where T : class { if (input == null) return new Failure<T, Error>(new ValidationError(422, $"Required input {parameter} was null.")); else return new Success<T, Error>(input); } public static Result<object, Error> IsNull(this IGuard guard, object input, string parameter) { return IsNull(input, parameter); } #endregion

Extend:

public static class FubarGuard { private static Result<Option<string>, Error> IsFubar(string input, string parameter) { if (input.ToLower() == "fubar") return new Failure<Option<string>, Error>(new ValidationError(422, $"Parameter {parameter} should not be f***ed up beyond all repair!")); else return new Success<Option<string>, Error>(Option<string>.Some(input)); } public static Result<Option<string>, Error> IsFubar(this IGuard guard, string input, string parameter) { var _ = Guard.Check.IsNullOrEmpty(input, parameter); if (_ is Failure<string, Error>) return new Success<Option<string>, Error>(Option<string>.None); else return IsFubar(input, parameter); } }

Test

[TestMethod] public void IsFubar_ShouldFailValidation_True() { var check = Guard.Check.IsFubar("fubar", "string"); Assert.IsTrue(check is Failure<Option<string>, Error>); } [TestMethod] public void IsFubar_ShouldSuccedNull_True() { var check = Guard.Check.IsFubar(null, "string"); Assert.IsTrue(check is Success<Option<string>, Error>); }