Add SmartEnumNameAttribute, a DataAnnotations ValidationAttribute

CONTRIBUTING.md

@@ -1,4 +1,4 @@
-# Contributing to Ardalis.GuardClauses
+# Contributing to Ardalis.SmartEnum
 
 We love your input! We want to make contributing to this project as easy and transparent as possible, whether it's:
 
@@ -31,15 +31,15 @@ You can just add a pull request out of the blue if you want, but it's much bette
 
 ## Getting Started
 
-Look for [issues marked with 'help wanted'](https://github.com/ardalis/guardclauses/issues?q=is%3Aissue+is%3Aopen+label%3A%22help+wanted%22) to find good places to start contributing.
+Look for [issues marked with 'help wanted'](https://github.com/ardalis/SmartEnum/issues?q=is%3Aissue+is%3Aopen+label%3A%22help+wanted%22) to find good places to start contributing.
 
 ## Any contributions you make will be under the MIT Software License
 
 In short, when you submit code changes, your submissions are understood to be under the same [MIT License](http://choosealicense.com/licenses/mit/) that covers this project.
 
-## Report bugs using Github's [issues](https://github.com/ardalis/guardclauses/issues)
+## Report bugs using Github's [issues](https://github.com/ardalis/SmartEnum/issues)
 
-We use GitHub issues to track public bugs. Report a bug by [opening a new issue](https://github.com/ardalis/GuardClauses/issues/new/choose); it's that easy!
+We use GitHub issues to track public bugs. Report a bug by [opening a new issue](https://github.com/ardalis/SmartEnum/issues/new/choose); it's that easy!
 
 ## Sponsor us
 

README.md

@@ -30,6 +30,7 @@
   * [Dapper support](#dapper-support)
   * [DapperSmartEnum](#dappersmartenum)
   * [Case Insensitive String Enum](#case-insensitive-string-enum)
+  * [Name Validation Attribute](#name-validation-attribute)
   * [Examples in the Real World](#examples-in-the-real-world)
   * [References](#references)
 
@@ -61,7 +62,7 @@ An implementation of a [type-safe object-oriented alternative](https://codeblog.
 
 ## Contributors
 
-Thanks to [Scott Depouw](https://github.com/sdepouw), [Antão Almada](https://github.com/aalmada), and [Nagasudhir Pulla](https://github.com/nagasudhirpulla) for help with this project!
+Thanks to [Scott DePouw](https://github.com/sdepouw), [Antão Almada](https://github.com/aalmada), and [Nagasudhir Pulla](https://github.com/nagasudhirpulla) for help with this project!
 
 # Install
 
@@ -828,7 +829,35 @@ var e2 = CaseInsensitiveEnum.FromValue("one");
 
 //e1 is equal to e2
 ```
+## Name Validation Attribute
+The DataAnnotations ValidationAttribute `SmartEnumNameAttribute` allows you to validate your models, mandating that when provided a value it must be matching the name of a given `SmartEnum`. This attribute allows `null` values (use `[Required]` to disallow nulls).
 
+In addition to specifying the `SmartEnum` to match, you may also pass additional parameters:
+- `allowCaseInsensitiveMatch` (default `false`)
+- `errorMessage` (default `"{0} must be one of: {1}"`): A format string to customize the error
+  - `{0}` is the name of the property being validated
+  - `{1}` is the comma-separated list of valid `SmartEnum` names
+
+### Example of Name Validation Attribute
+```csharp
+public sealed class ExampleSmartEnum : SmartEnum<ExampleSmartEnum>
+{
+    public static readonly ExampleSmartEnum Foo = new ExampleSmartEnum(nameof(Foo), 1);
+    public static readonly ExampleSmartEnum Bar = new ExampleSmartEnum(nameof(Bar), 2);
+
+    private ExampleSmartEnum(string name, int value) : base(name, value) { }
+}
+
+public class ExampleModel
+{
+    [Required]
+    [SmartEnumName(typeof(ExampleSmartEnum)]
+    public string MyExample { get; set; } // must be "Foo" or "Bar"
+
+    [SmartEnumName(typeof(ExampleSmartEnum), allowCaseInsensitiveMatch: true)]
+    public string CaseInsensitiveExample { get; set; } // "Foo", "foo", etc. allowed; null also allowed here
+}
+```
 
 ## Examples in the Real World
 

src/SmartEnum/SmartEnumNameAttribute.cs

@@ -0,0 +1,81 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.Linq;
+using System.Reflection;
+using System.Runtime.CompilerServices;
+
+namespace Ardalis.SmartEnum
+{
+    /// <summary>
+    /// A <see cref="ValidationAttribute"/> that ensures the provided value matches the
+    /// <see cref="SmartEnum{TEnum}.Name"/> of a <see cref="SmartEnum{TEnum}"/>/<see cref="SmartEnum{TEnum,TValue}"/>.
+    /// Nulls and non-<see cref="string"/> values are considered valid
+    /// (add <see cref="RequiredAttribute"/> if you want the field to be required).
+    /// </summary>
+    public class SmartEnumNameAttribute : ValidationAttribute
+    {
+        private readonly bool _allowCaseInsensitiveMatch;
+        private readonly Type _smartEnumType;
+
+        /// <param name="smartEnumType">The expected SmartEnum type.</param>
+        /// <param name="propertyName">The name of the property that the attribute is being used on.</param>
+        /// <param name="allowCaseInsensitiveMatch">
+        ///     Unless this is true, only exact case matching the
+        ///     <see cref="SmartEnum{TEnum}" /> Name will validate.
+        /// </param>
+        /// <param name="errorMessage">
+        ///     Message template to show when validation fails. {0} is <paramref name="propertyName" /> and
+        ///     {1} is the comma-separated list of SmartEnum names.
+        /// </param>
+        /// <exception cref="ArgumentNullException">When any of the constructor parameters are null.</exception>
+        /// <exception cref="InvalidOperationException">
+        ///     When <paramref name="smartEnumType" /> is not a
+        ///     <see cref="SmartEnum{TEnum}" /> or <see cref="SmartEnum{TEnum,TValue}" />
+        /// </exception>
+        public SmartEnumNameAttribute(
+            Type smartEnumType,
+            [CallerMemberName] string propertyName = null,
+            bool allowCaseInsensitiveMatch = false,
+            string errorMessage = "{0} must be one of: {1}"
+        )
+        {
+            if (smartEnumType is null) throw new ArgumentNullException(nameof(smartEnumType));
+            if (propertyName is null) throw new ArgumentNullException(nameof(propertyName));
+            if (errorMessage is null) throw new ArgumentNullException(nameof(errorMessage));
+            List<string> smartEnumBaseTypes = new() { typeof(SmartEnum<>).Name, typeof(SmartEnum<,>).Name };
+            if (smartEnumType.BaseType == null || !smartEnumBaseTypes.Contains(smartEnumType.BaseType.Name))
+                throw new InvalidOperationException($"{nameof(smartEnumType)} must be a SmartEnum.");
+            _smartEnumType = smartEnumType;
+            _allowCaseInsensitiveMatch = allowCaseInsensitiveMatch;
+            ErrorMessage = string.Format(errorMessage, propertyName, string.Join(", ", GetValidSmartEnumNames()));
+        }
+
+        public override bool IsValid(object value)
+        {
+            if (value is not string name) return true;
+
+            return _allowCaseInsensitiveMatch
+                ? GetValidSmartEnumNames().Contains(name, StringComparer.InvariantCultureIgnoreCase)
+                : GetValidSmartEnumNames().Contains(name);
+        }
+
+        private List<string> GetValidSmartEnumNames()
+        {
+            List<string> validNames = new();
+            var typeWithList = _smartEnumType.BaseType!.Name == typeof(SmartEnum<>).Name
+                ? _smartEnumType.BaseType.BaseType!
+                : _smartEnumType.BaseType!;
+            var listProp = typeWithList.GetProperty("List", BindingFlags.Public | BindingFlags.Static);
+            var rawValue = listProp!.GetValue(null);
+            foreach (var val in (IEnumerable)rawValue!)
+            {
+                var namePropInfo = val.GetType().GetProperty("Name", BindingFlags.Public | BindingFlags.Instance);
+                var value = namePropInfo!.GetValue(val);
+                if (value is string name) validNames.Add(name);
+            }
+            return validNames;
+        }
+    }
+}

test/SmartEnum.UnitTests/SmartEnumNameAttributeTests.cs

@@ -0,0 +1,177 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.Linq;
+using FluentAssertions;
+using FluentAssertions.Execution;
+using Xunit;
+
+namespace Ardalis.SmartEnum.UnitTests
+{
+    public class SmartEnumNameAttributeTests
+    {
+        [Fact]
+        public void ThrowsWhenCtorGetsNullType()
+        {
+            Action ctorCall = () => new SmartEnumNameAttribute(null);
+
+            ctorCall.Should().ThrowExactly<ArgumentNullException>();
+        }
+
+        [Fact]
+        public void ThrowsWhenCtorGetsNullPropertyName()
+        {
+            Action ctorCall = () => new SmartEnumNameAttribute(typeof(TestSmartEnum), propertyName: null, errorMessage: "Some Error Message");
+
+            ctorCall.Should().ThrowExactly<ArgumentNullException>();
+        }
+
+        [Fact]
+        public void ThrowsWhenCtorGetsNullErrorMessage()
+        {
+            Action ctorCall = () => new SmartEnumNameAttribute(typeof(TestSmartEnum), errorMessage: null);
+
+            ctorCall.Should().ThrowExactly<ArgumentNullException>();
+        }
+
+        [Fact]
+        public void ThrowsWhenCtorGetsNonSmartEnumType()
+        {
+            Action ctorCall = () => new SmartEnumNameAttribute(typeof(SmartEnumNameAttributeTests));
+
+            ctorCall.Should().ThrowExactly<InvalidOperationException>();
+        }
+
+        [Fact]
+        public void DoesNotThrowWhenCtorForSmartEnumWithDifferentKeyType()
+        {
+            Action ctorCall = () => new SmartEnumNameAttribute(typeof(TestSmartEnumWithStringKeyType));
+
+            ctorCall.Should().NotThrow();
+        }
+
+        [Fact]
+        public void ReturnsErrorMessageContainingPropertyNameAndAllPossibleSmartEnumValues()
+        {
+            var model = new TestValidationModel { SomeProp = "foo" };
+            var validationContext = new ValidationContext(model, null, null);
+            List<ValidationResult> validationResults = new List<ValidationResult>();
+
+            Validator.TryValidateObject(model, validationContext, validationResults, true);
+
+            using (new AssertionScope())
+            {
+                validationResults.Should().HaveCount(1);
+                string errorMessage = validationResults.Single().ErrorMessage;
+                errorMessage.Should().Contain(nameof(TestValidationModel.SomeProp));
+                errorMessage.Should().Contain(TestSmartEnum.TestFoo.Name);
+                errorMessage.Should().Contain(TestSmartEnum.TestBar.Name);
+                errorMessage.Should().Contain(TestSmartEnum.TestFizz.Name);
+                errorMessage.Should().Contain(TestSmartEnum.TestBuzz.Name);
+            }
+        }
+
+        [Fact]
+        public void IsValidGivenNonString()
+        {
+            var attribute = new SmartEnumNameAttribute(typeof(TestSmartEnum));
+            object nonString = new { };
+
+            bool isValid = attribute.IsValid(nonString);
+
+            isValid.Should().BeTrue();
+        }
+
+        [Fact]
+        public void IsValidGivenNullString()
+        {
+            var attribute = new SmartEnumNameAttribute(typeof(TestSmartEnum));
+            string nullString = null;
+
+            bool isValid = attribute.IsValid(nullString);
+
+            isValid.Should().BeTrue();
+        }
+
+        [Fact]
+        public void IsValidGivenNullNonString()
+        {
+            var attribute = new SmartEnumNameAttribute(typeof(TestSmartEnum));
+            object nullObject = null;
+
+            bool isValid = attribute.IsValid(nullObject);
+
+            isValid.Should().BeTrue();
+        }
+
+        [Fact]
+        public void IsValidForEachMemberOfAGivenSmartEnum()
+        {
+            var attribute = new SmartEnumNameAttribute(typeof(TestSmartEnum));
+            using (new AssertionScope())
+            {
+                foreach (var name in TestSmartEnum.List.Select(at => at.Name))
+                {
+                    bool isValid = attribute.IsValid(name);
+                    isValid.Should().BeTrue();
+                }
+            }
+        }
+
+        [Fact]
+        public void IsValidForCaseInsensitiveStringWhenCaseInsensitiveMatchingEnabled()
+        {
+            var attribute = new SmartEnumNameAttribute(typeof(TestSmartEnum), allowCaseInsensitiveMatch: true);
+            var caseInsensitiveSource = TestSmartEnum.TestFoo.Name.ToLower();
+
+            bool isValid = attribute.IsValid(caseInsensitiveSource);
+
+            isValid.Should().BeTrue();
+        }
+
+        [Fact]
+        public void IsNotValidForCaseInsensitiveStringWhenCaseInsensitiveMatchingDisabled()
+        {
+            var attribute = new SmartEnumNameAttribute(typeof(TestSmartEnum));
+            var caseInsensitiveSource = TestSmartEnum.TestFoo.Name.ToLower();
+
+            bool isValid = attribute.IsValid(caseInsensitiveSource);
+
+            isValid.Should().BeFalse();
+        }
+
+        [Theory]
+        [InlineData("   ")]
+        [InlineData("Some Wrong Value")]
+        [InlineData("25")]
+        public void IsNotValidGivenNonSmartEnumNames(string invalidName)
+        {
+            var attribute = new SmartEnumNameAttribute(typeof(TestSmartEnum));
+
+            bool isValid = attribute.IsValid(invalidName);
+
+            isValid.Should().BeFalse();
+        }
+
+        private class TestValidationModel
+        {
+            [SmartEnumName(typeof(TestSmartEnum))]
+            public string SomeProp { get; set; }
+        }
+
+        private class TestSmartEnum : SmartEnum<TestSmartEnum>
+        {
+            public static readonly TestSmartEnum TestFoo = new TestSmartEnum(nameof(TestFoo), 1);
+            public static readonly TestSmartEnum TestBar = new TestSmartEnum(nameof(TestBar), 2);
+            public static readonly TestSmartEnum TestFizz = new TestSmartEnum(nameof(TestFizz), 3);
+            public static readonly TestSmartEnum TestBuzz = new TestSmartEnum(nameof(TestBuzz), 4);
+
+            private TestSmartEnum(string name, int value) : base(name, value) { }
+        }
+
+        private class TestSmartEnumWithStringKeyType : SmartEnum<TestSmartEnumWithStringKeyType, string>
+        {
+            private TestSmartEnumWithStringKeyType(string name, string value) : base(name, value) { }
+        }
+    }
+}