Initial Commit from Swagger-Gen

src/IO.Swagger/Attributes/ValidateModelStateAttribute.cs

@@ -0,0 +1,61 @@
+using System.ComponentModel.DataAnnotations;
+using System.Reflection;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.Controllers;
+using Microsoft.AspNetCore.Mvc.Filters;
+using Microsoft.AspNetCore.Mvc.ModelBinding;
+
+namespace IO.Swagger.Attributes
+{
+    /// <summary>
+    /// Model state validation attribute
+    /// </summary>
+    public class ValidateModelStateAttribute : ActionFilterAttribute
+    {
+        /// <summary>
+        /// Called before the action method is invoked
+        /// </summary>
+        /// <param name="context"></param>
+        public override void OnActionExecuting(ActionExecutingContext context)
+        {
+            // Per https://blog.markvincze.com/how-to-validate-action-parameters-with-dataannotation-attributes/
+            var descriptor = context.ActionDescriptor as ControllerActionDescriptor;
+            if (descriptor != null)
+            {
+                foreach (var parameter in descriptor.MethodInfo.GetParameters())
+                {
+                    object args = null;
+                    if (context.ActionArguments.ContainsKey(parameter.Name))
+                    { 
+                        args = context.ActionArguments[parameter.Name];
+                    }
+
+                    ValidateAttributes(parameter, args, context.ModelState);
+                }
+            }
+
+            if (!context.ModelState.IsValid)
+            {
+                context.Result = new BadRequestObjectResult(context.ModelState);
+            }
+        }
+
+        private void ValidateAttributes(ParameterInfo parameter, object args, ModelStateDictionary modelState)
+        {
+            foreach (var attributeData in parameter.CustomAttributes)
+            {
+                var attributeInstance = parameter.GetCustomAttribute(attributeData.AttributeType);
+
+                var validationAttribute = attributeInstance as ValidationAttribute;
+                if (validationAttribute != null)
+                {
+                    var isValid = validationAttribute.IsValid(args);
+                    if (!isValid)
+                    {
+                        modelState.AddModelError(parameter.Name, validationAttribute.FormatErrorMessage(parameter.Name));
+                    }
+                }
+            }
+        }
+    }
+}