Questions on UI for ASP.NET MVC Forum

2 questions

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69 views

Getting unable to cast the object of filecontectresult to string in kendo captcha

Hi,

I am trying to implement Kendo Captcha. I tried to implement same way as in this article.

ASP.NET MVC Captcha Component Validation - Telerik UI for ASP.NET MVC

But I am getting below error. what am I doing wrong?

My code is like this

@(Html.Kendo().Captcha()
                            .Name("Captcha")
                            .CaptchaImage((string)ViewData["Captcha"])
                            .CaptchaId((string)ViewData["CaptchaID"])
                            .DataCaptchaField("Captcha") // The field containing the Captcha from the server-side should be called Captcha.
                            .DataCaptchaIdField("CaptchaID") // The field containing the Captcha's ID from the server-side should be called CaptchaID.
                            .Handler(handler => handler.Action("Reset", "IUA"))
                            .ValidationHandler(handler => handler.Action("Validate", "IUA"))
                            .ValidateOnBlur(true)
                        )

namespace Portal.Controllers
{
    public class IuaController : Controller
    {
        // GET: Iua
        public ActionResult Index ( string pin )
        {
            var model = portalServices.getExistingData();


            if (string.IsNullOrEmpty(model.CaptchaID))
            {
                GenerateNewCaptcha();
            }
            else
            {
                CaptchaImage captchaImage = (CaptchaImage)Session["captcha" + model.CaptchaID];

                if (captchaImage != null && CaptchaHelper.Validate(captchaImage, model.Captcha.ToUpperInvariant()))
                {
                    ModelState.Clear();
                    GenerateNewCaptcha();
                }
            }

            //return View();

            return View(model);
        }

        private void GenerateNewCaptcha()
        {
            CaptchaImage captchaImage = CaptchaHelper.GetNewCaptcha();

            Session["captcha" + captchaImage.UniqueId] = captchaImage;

            ViewData["Captcha"] = GetCatchaImage(captchaImage.UniqueId);//Url.Action("image", "IUA", new { captchaId = captchaImage.UniqueId });
            ViewData["CaptchaID"] = captchaImage.UniqueId;
        }

        public ActionResult Reset()
        {
            CaptchaImage newCaptcha = CaptchaHelper.GetNewCaptcha();

            Session["captcha" + newCaptcha.UniqueId] = newCaptcha;

            return Json(new
            {
                captcha = GetCatchaImage(newCaptcha.UniqueId),//Url.Action("image", "IUA", new { captchaId = newCaptcha.UniqueId }),
                captchaId = newCaptcha.UniqueId
            }, JsonRequestBehavior.AllowGet);
        }

        public ActionResult Image(string captchaId)
        {
            CaptchaImage captcha = (CaptchaImage)Session["captcha" + captchaId];
            var image = CaptchaHelper.RenderCaptcha(captcha);
            byte[] bmpBytes;

            using (MemoryStream ms = new MemoryStream())
            {
                image.Save(ms, ImageFormat.Png);
                bmpBytes = ms.ToArray();
            }

            return File(bmpBytes, "image/png");
        }

        public ActionResult GetCatchaImage(string captchaId)
        {
            CaptchaImage captcha = (CaptchaImage)Session["captcha" + captchaId];
            var image = CaptchaHelper.RenderCaptcha(captcha);
            byte[] bmpBytes;

            using (MemoryStream ms = new MemoryStream())
            {
                image.Save(ms, ImageFormat.Png);
                bmpBytes = ms.ToArray();
            }

            return File(bmpBytes, "image/png");
        }

        public ActionResult Audio(string captchaId)
        {
            CaptchaImage captcha = (CaptchaImage)Session["captcha" + captchaId];
            byte[] bmpBytes;

            using (MemoryStream audio = CaptchaHelper.SpeakText(captcha))
            {
                bmpBytes = audio.ToArray();
            }

            return File(bmpBytes, "audio/wav");
        }

        public ActionResult Validate(string captchaId, string captcha)
        {
            CaptchaImage captchaImage = (CaptchaImage)Session["captcha" + captchaId];

            return Json(CaptchaHelper.Validate(captchaImage, captcha.ToUpperInvariant()), JsonRequestBehavior.AllowGet);
        }
    }
}

Model class

    public class IuaModel
    {
        [Key]
        public string Pin { get; set; }

        [Display(Name = "Ticket #")]
        public long Id { get; set; }

        [Required]
        [Display(Name = "First Name")]
        public string FirstName { get; set; }

        [Display(Name = "Middle Initial")]
        public string MiddleInitial { get; set; }

        [Required]
        [Display(Name = "Last Name")]
        public string LastName { get; set; }

        [Display(Name = "Facility Name")]
        public string FacilityName { get; set; }

        private string _captchaValue;

        public string Captcha
        {
            get
            {
                return string.IsNullOrEmpty(_captchaValue) ? "" : _captchaValue;
            }
            set
            {
                _captchaValue = value;
            }
        }

        public string CaptchaID { get; set; }
    }

Captcha

answered on 20 Mar 2023

1 answer

646 views

Captcha Image not reloaded on Reset

I'm using Captcha for MVC.

I got everything working on ASP.Net 6, except for the Reset.

The Reset-Endpoint is called properly and gives back sucess with the CaptchaModel (captchaUrl, captchaId).

But the Url is not set in the src-Tag of the Captcha-Image, so the Endpoint for getting the rendered Captcha-Image is not called, instead the src-tag is just emptied and the field becomes grey.

When I set the Image-Url I got in the xhr-Request into the src-Tag manually it works as expected.

Audio and Validation working as expected.

XHR:

View Code:

  <p>Captcha:</p>
      @(Html.Kendo().Captcha()
                    .Name("captcha")
                    .CaptchaImage((string)ViewData["Captcha"])
                    .CaptchaId((string)ViewData["CaptchaID"])
                    .DataCaptchaField("Captcha") 
                    .DataCaptchaIdField("CaptchaID") 
                    .Handler(handler => handler.Action("Reset", "Captcha"))
                    .AudioHandlerFunction("audioHandler")
                    .ValidationHandler(handler => handler.Action("Validate", "Captcha"))
                    .ValidateOnBlur(true)
                    .ResetButton(true)
                    .AudioButton(true)
       )

<script>
  $(document).on("kendoReady",
  function() {
        $("#mailform").kendoValidator();
   });

  function audioHandler(args) {
         args.success("@Url.Action("Audio", "Captcha")?captchaId=" + args.data.CaptchaID);
  }
</script>

Controller:

  public class CaptchaController : Controller
    {
        public ActionResult Image(string captchaId)
        {
            CaptchaImage captcha = (CaptchaImage)HttpContext.Session.Get<CaptchaImage>("captcha" + captchaId);
            var image = CaptchaHelper.RenderCaptcha(captcha);
            byte[] bmpBytes;

            using (MemoryStream ms = new MemoryStream())
            {
                image.Save(ms, ImageFormat.Png);
                bmpBytes = ms.ToArray();
            }

            return File(bmpBytes, "image/png");
        }

        [HttpGet]
        public ActionResult Reset()
        {
            CaptchaImage newCaptcha = CaptchaHelper.GetNewCaptcha();

            HttpContext.Session.Set("captcha" + newCaptcha.UniqueId,  newCaptcha);

            return Json(new CaptchaModel { Captcha = Url.Action("image", "captcha", new { captchaID = newCaptcha.UniqueId }), CaptchaID = newCaptcha.UniqueId });
        }

        public ActionResult Audio(string captchaId)
        {
            CaptchaImage captcha = (CaptchaImage)HttpContext.Session.Get<CaptchaImage>("captcha" + captchaId);

            byte[] bmpBytes;

            using (MemoryStream audio = CaptchaHelper.SpeakText(captcha))
            {
                bmpBytes = audio.ToArray();
            }

            return File(bmpBytes, "audio/wav");
        }

        [HttpGet]
        public ActionResult Validate(CaptchaModel model)
        {
            CaptchaImage captchaImage = (CaptchaImage) HttpContext.Session.Get<CaptchaImage>("captcha" + model.CaptchaID);
            return Json(CaptchaHelper.Validate(captchaImage, model.Captcha.ToUpperInvariant()));
        }
    }