Add optional filter to AddFluentValidationAutoValidation() (#20)

src/FluentValidation.AspNetCore/FluentValidationModelValidatorProvider.cs

@@ -37,22 +37,31 @@ namespace FluentValidation.AspNetCore;
 public class FluentValidationModelValidatorProvider : IModelValidatorProvider {
 	private readonly bool _implicitValidationEnabled;
 	private readonly bool _implicitRootCollectionElementValidationEnabled;
+	private readonly Func<Type, bool> _filter;
 
 	public FluentValidationModelValidatorProvider(bool implicitValidationEnabled)
-		: this(implicitValidationEnabled, false) {
+		: this(implicitValidationEnabled, false, default) {
 	}
 
 	public FluentValidationModelValidatorProvider(
 		bool implicitValidationEnabled,
-		bool implicitRootCollectionElementValidationEnabled) {
+		bool implicitRootCollectionElementValidationEnabled)
+		: this(implicitValidationEnabled, implicitRootCollectionElementValidationEnabled, default) {
+	}
+
+	public FluentValidationModelValidatorProvider(
+		bool implicitValidationEnabled,
+		bool implicitRootCollectionElementValidationEnabled,
+		Func<Type, bool> filter) {
 		_implicitValidationEnabled = implicitValidationEnabled;
 		_implicitRootCollectionElementValidationEnabled = implicitRootCollectionElementValidationEnabled;
+		_filter = filter;
 	}
 
 	public virtual void CreateValidators(ModelValidatorProviderContext context) {
 		context.Results.Add(new ValidatorItem {
 			IsReusable = false,
-			Validator = new FluentValidationModelValidator(_implicitValidationEnabled, _implicitRootCollectionElementValidationEnabled),
+			Validator = new FluentValidationModelValidator(_implicitValidationEnabled, _implicitRootCollectionElementValidationEnabled, _filter),
 		});
 	}
 }
@@ -63,16 +72,25 @@ public virtual void CreateValidators(ModelValidatorProviderContext context) {
 public class FluentValidationModelValidator : IModelValidator {
 	private readonly bool _implicitValidationEnabled;
 	private readonly bool _implicitRootCollectionElementValidationEnabled;
+	private readonly Func<Type, bool> _filter;
 
 	public FluentValidationModelValidator(bool implicitValidationEnabled)
-		: this(implicitValidationEnabled, false) {
+		: this(implicitValidationEnabled, false, default) {
 	}
 
 	public FluentValidationModelValidator(
 		bool implicitValidationEnabled,
-		bool implicitRootCollectionElementValidationEnabled) {
+		bool implicitRootCollectionElementValidationEnabled)
+		: this(implicitValidationEnabled, implicitRootCollectionElementValidationEnabled, default) {
+	}
+
+	public FluentValidationModelValidator(
+		bool implicitValidationEnabled,
+		bool implicitRootCollectionElementValidationEnabled,
+		Func<Type, bool> filter) {
 		_implicitValidationEnabled = implicitValidationEnabled;
 		_implicitRootCollectionElementValidationEnabled = implicitRootCollectionElementValidationEnabled;
+		_filter = filter;
 	}
 
 	public virtual IEnumerable<ModelValidationResult> Validate(ModelValidationContext mvContext) {
@@ -140,6 +158,12 @@ public virtual IEnumerable<ModelValidationResult> Validate(ModelValidationContex
 	}
 
 	protected bool ShouldSkip(ModelValidationContext mvContext) {
+		//Apply custom filter (if specified)
+		//validation will be skipped unless we match on this filter
+		if (_filter != null && !_filter.Invoke(mvContext.ModelMetadata.ModelType)) {
+			return true;
+		}
+
 		// Skip if there's nothing to process.
 		if (mvContext.Model == null) {
 			return true;

src/FluentValidation.AspNetCore/FluentValidationMvcConfiguration.cs

@@ -60,6 +60,15 @@ public class FluentValidationAutoValidationConfiguration {
 	/// Setting this to true will disable DataAnnotations and only run FluentValidation.
 	/// </summary>
 	public bool DisableDataAnnotationsValidation { get; set; }
+
+
+	/// <summary>
+	/// When specified, automatic validation will only apply to the types matched by the filter.
+	/// If the filter does not match, automatic validation will not be applied.  This can be useful
+	/// for specific situations where you want to opt in/out of automatic validation
+	/// Example: Filter = type => type == typeof(Model)
+	/// </summary>
+	public Func<Type, bool> Filter { get; set; }
 }
 
 /// <summary>

src/FluentValidation.AspNetCore/FluentValidationMvcExtensions.cs

@@ -139,7 +139,8 @@ public static IServiceCollection AddFluentValidationAutoValidation(this IService
 			if (!options.ModelValidatorProviders.Any(x => x is FluentValidationModelValidatorProvider)) {
 				options.ModelValidatorProviders.Insert(0, new FluentValidationModelValidatorProvider(
 					config.ImplicitlyValidateChildProperties,
-					config.ImplicitlyValidateRootCollectionElements));
+					config.ImplicitlyValidateRootCollectionElements,
+					config.Filter));
 			}
 		});
 

src/FluentValidation.Tests.AspNetCore/Controllers/TestController.cs

@@ -206,6 +206,22 @@ public async Task<ActionResult> UpdateModel() {
 		return TestResult();
 	}
 
+	public ActionResult AutoFilter(AutoFilterModel test) { 
+		return TestResult(); 
+	}
+
+	public ActionResult AutoFilterParent(AutoFilterParentModel test) { 
+		return TestResult(); 
+	}
+
+	public ActionResult AutoFilterRootCollection(List<AutoFilterModel> test) { 
+		return TestResult(); 
+	}
+
+	public ActionResult AutoFilterParentWithCollection(AutoFilterParentWithCollectionModel test) { 
+		return TestResult(); 
+	}
+
 	private ActionResult TestResult() {
 		var errors = new List<SimpleError>();