Added plain ValidationAttribute for model-based validation

reCAPTCHA.AspNetCore.Example/Controllers/SomeAPIControlelr.cs

@@ -0,0 +1,23 @@
+using Microsoft.AspNetCore.Mvc;
+using reCAPTCHA.AspNetCore.Attributes;
+using reCAPTCHA.AspNetCore.Example.Models;
+using System.ComponentModel.DataAnnotations;
+
+namespace reCAPTCHA.AspNetCore.Example.Controllers
+{
+    [ApiController]
+    public class SomeApiController : Controller
+    {
+        [HttpGet]
+        public ActionResult SomeAction(string someValue, [Required, RecaptchaResponse] string reCaptchaResponseCode)
+        {
+            return Ok($"I have done something with {someValue} after reCaptcha was validated");
+        }
+
+        [HttpPost]
+        public ActionResult SomeAction(OtherModel model)
+        {
+            return Ok($"I have done something after reCaptcha was validated");
+        }
+    }
+}

reCAPTCHA.AspNetCore.Example/Models/OtherModel.cs

@@ -0,0 +1,10 @@
+using reCAPTCHA.AspNetCore.Attributes;
+
+namespace reCAPTCHA.AspNetCore.Example.Models
+{
+    public class OtherModel
+    {
+        [RecaptchaResponse(MinimumScore = 0.5)]
+        public string ReCaptchaResponseCode { get; set; }
+    }
+}

reCAPTCHA.AspNetCore/Attributes/RecaptchaResponseAttribute.cs

@@ -0,0 +1,62 @@
+using System;
+using System.ComponentModel.DataAnnotations;
+using System.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace reCAPTCHA.AspNetCore.Attributes
+{
+    /// <summary>
+    /// Validates reCaptcha response code bound to a property, parameter or field.
+    /// </summary>
+    /// <seealso cref="ValidationAttribute" />
+    /// <seealso cref="IRecaptchaService.Validate(string)"/>
+    [AttributeUsage(AttributeTargets.Parameter | AttributeTargets.Property | AttributeTargets.Field)]
+	public class RecaptchaResponseAttribute : ValidationAttribute
+	{
+		/// <summary>
+		/// Gets a value that indicates whether the attribute requires validation context.
+		/// </summary>
+		public override bool RequiresValidationContext => true;
+
+        /// <summary>
+        /// Gets or sets the minimum score.
+        /// </summary>
+        /// <value>
+        /// The minimum score.
+        /// </value>
+        /// <seealso cref="ValidateRecaptchaAttribute._minimumScore"/>
+        public double MinimumScore { get; set; }
+
+        /// <summary>
+        /// Returns wether the captcha validation was deemed successful based on the value of a member to attribute has been applied to.
+        /// </summary>
+        /// <param name="value">The value to validate.</param>
+        /// <param name="validationContext">The context information about the validation operation.</param>
+        /// <returns>
+        /// An instance of the <see cref="System.ComponentModel.DataAnnotations.ValidationResult" /> class.
+        /// </returns>
+        /// <exception cref="ConfigurationErrorsException">When reCaptcha has not been configured.</exception>
+        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
+		{
+			if (!(value is string responseCode)
+					|| string.IsNullOrWhiteSpace(responseCode))
+				return null;
+
+			var validationservice = validationContext.GetService<IRecaptchaService>();
+
+            if(validationservice is null)
+                throw new ConfigurationErrorsException($"{typeof(IRecaptchaService).Assembly.GetName().Name} has not been configured");
+
+			var response = validationservice.Validate(responseCode).Result;
+
+            if (response.success 
+                && (response.score == 0 || response.score >= MinimumScore))
+
+                return ValidationResult.Success;
+
+            else
+
+                return new ValidationResult(FormatErrorMessage(validationContext.DisplayName));
+        }
+	}
+}

reCAPTCHA.AspNetCore/Attributes/ValidateRecaptchaAttribute.cs

@@ -4,6 +4,7 @@
 
 namespace reCAPTCHA.AspNetCore.Attributes
 {
+
     /// <summary>
     /// Validates Recaptcha submitted by a form using: @Html.Recaptcha(RecaptchaSettings.Value)
     /// </summary>

reCAPTCHA.AspNetCore/reCAPTCHA.AspNetCore.csproj

@@ -58,4 +58,8 @@
       <PackagePath></PackagePath>
     </None>
   </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="System.Configuration.ConfigurationManager" Version="5.0.0" />
+  </ItemGroup>
 </Project>