hCaptcha Service for use with a Surface Controller or any MVC Controller (With light modifications)

AnySurfaceController.cs

public class AnySurfaceController : SurfaceController
{
    private readonly IhCaptchaService _hCaptchaService;
    public AnySurfaceController(IhCaptchaService hCaptchaService)
    {
        _hCaptchaService = hCaptchaService;
    }

    [ValidateAntiForgeryToken]
    [HttpPost]
    public async Task<ActionResult> FormPost(FormModel order)
    {
        var request = Request;
        var valid = _hCaptchaService.Validate(request.UserHostAddress, request.Form["h-captcha-response"]);
        if (!valid)
        {
            ModelState.AddModelError("hCaptcha", "You did not pass the human validation, please try again");
            return CurrentUmbracoPage();
        }
        return CurrentUmbracoPage();
    }
}

AppSettingsManager.cs

public static class AppSettingsManager
    {
        public static string hCaptchaSiteKey()
        {
            if (ConfigurationManager.AppSettings["hCaptchaSiteKey"] != null)
                return ConfigurationManager.AppSettings["hCaptchaSiteKey"];

            throw new Exception("\"hCaptchaSiteKey\" is missing in AppSettings.");
        }
        
        public static string hCaptchaSecretKey()
        {
            if (ConfigurationManager.AppSettings["hCaptchaSecretKey"] != null)
                return ConfigurationManager.AppSettings["hCaptchaSecretKey"];

            throw new Exception("\"hCaptchaSecretKey\" is missing in AppSettings.");
        }
    }

hCaptchaComposer.cs

public class hCaptchaComposer : IUserComposer
{
    public void Compose(Composition composition)
    {
        composition.Register<IhCaptchaService, hCaptchaService>(Lifetime.Request);
    }
}

hCaptchaService.cs

public class hCaptchaService : IhCaptchaService
{
    public bool Validate(string remoteIp, string responseText)
    {
        using (var client = new HttpClient())
        {
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/x-www-form-urlencoded"));
            client.DefaultRequestHeaders.Add("Accept", "*/*");

            var parameters = new List<KeyValuePair<string, string>>
            {
                new KeyValuePair<string, string>("response", responseText),
                new KeyValuePair<string, string>("secret", AppSettingsManager.hCaptchaSecretKey()),
                new KeyValuePair<string, string>("remoteip", remoteIp)
            };

            var request = new HttpRequestMessage(HttpMethod.Post, "https://hcaptcha.com/siteverify")
            {
                Content = new FormUrlEncodedContent(parameters)
            };

            var response = client.SendAsync(request).Result;

            if (response.IsSuccessStatusCode)
            {
                var jsonString = response.Content.ReadAsStringAsync();
                jsonString.Wait();

                var result = JsonConvert.DeserializeObject<hCaptchaVerifyResponse>(jsonString.Result);

                if (result.Success)
                {
                    return true;
                }
            }

            if (!response.IsSuccessStatusCode)
            {
                return false;
            }
        }

        return false;
    }
}

hCaptchaVerifyResponse.cs

using System;
using Newtonsoft.Json;

namespace UmbHost.Shared.Models.hCaptcha
{
    /// <summary>
    /// Response Model to get the verification result
    /// </summary>
    /// <remarks>https://docs.hcaptcha.com/#server</remarks>
    public class hCaptchaVerifyResponse
    {
        /// <summary>
        /// indicates if verify was successfully or not
        /// </summary>
        /// <remarks>https://docs.hcaptcha.com/#server</remarks>
        [JsonProperty("success")]
        public bool Success { get; set; }

        /// <summary>
        /// timestamp of the captcha (ISO format yyyy-MM-dd'T'HH:mm:ssZZ)
        /// </summary>
        /// <remarks>https://docs.hcaptcha.com/#server</remarks>
        [JsonProperty("challenge_ts")]
        public DateTimeOffset Timestamp { get; set; }

        /// <summary>
        /// the hostname of the site where the captcha was solved
        /// </summary>
        /// <remarks>https://docs.hcaptcha.com/#server</remarks>
        [JsonProperty("hostname")]
        public string Hostname { get; set; }

        /// <summary>
        /// optional: whether the response will be credited
        /// </summary>
        /// <remarks>https://docs.hcaptcha.com/#server</remarks>
        [JsonProperty("credit")]
        public bool Credit { get; set; }

        /// <summary>
        /// string based error code array
        /// </summary>
        /// <remarks>https://docs.hcaptcha.com/#server</remarks>
        [JsonProperty("error-codes")]
        public string[] ErrorCodes { get; set; }
    }
}

IhCaptchaService.cs

public interface IhCaptchaService
{
    bool Validate(string remoteIp, string responseText);
}

ViewWithForm.cshtml

@using (Html.BeginUmbracoForm("FormPost", "AnySurface", null, new {autocomplete = "off"}, FormMethod.Post))
{
    @Html.AntiForgeryToken()
    <div class="h-captcha" data-sitekey="@AppSettingsManager.hCaptchaSiteKey()"></div>
}

<script src="https://hcaptcha.com/1/api.js"></script>

Web.Config

Add the below app settings:

    <add key="hCaptchaSiteKey" value="" />
    <add key="hCaptchaSecretKey" value="" />