arsanjani / Easy-Captcha

An efficient and secured alternative of Google reCAPTCHA for .NET

Easy Captcha

An efficient and secured alternative of Google reCAPTCHA for ASP.NET which has been written with C#. If you are being tired of struggling with Google reCAPTCHA and also worried about performance and banning issue with it, just take a minute to go through it for your consideration. I am certain that you won't be regret.

How to use

• Install it from Nuget:

  Install-Package EasyCaptchaCore -Version 1.0.1
  

• Add ICaptchaService to your Statrup like this:

  services.AddTransient<ICaptchaService, CaptchaService>();

• Enable Session in Configure method like this:

  app.UseSession();

• Enable session IdleTimeout in your ConfigureServices. You can change the session timeout if you want. It uses to store the Captcha in the user session securely.

  services.AddSession(options =>
            {
                options.IdleTimeout = TimeSpan.FromMinutes(10);
            });

• Use the code below in your View Layout:

  <img src="~/Captcha" alt="Captcha" />

• In order to randomly change the Captcha text by clicking on it, you can use the code below:

  <img src="~/Captcha" alt="Captcha" style="cursor: pointer;" onclick="refreshImage(this);" />

  <script type="text/javascript">
            refreshImage = function (img) {
                var source = img.src;
                img.src = '';
  
                source = source.split('?')[0];
                source = source + '?' + new Date().getTime();
  
                img.src = source;
            }
  </script>

• Use the code below to compare the real Captcha with the user input:

  [HttpPost]
  public ActionResult Index(CaptchaModel model)
  {
      var realCaptcha = HttpContext.Session.GetString("captcha").ToLower();
      if (realCaptcha != model.Captcha)
          model.Message = "Ops...Wrong captcha!";
      else
          model.Message = "Congrats! Captcha has been matched!";
      return View(model);
  }

• You can change the length of the captcha by the code below. (Default value is 5):

  <img src="~/Captcha?l=6" alt="Captcha" />

• You can change the background color of the captcha by the code below either by writting the color name or the keyword random. (Default is transparent):

  <img src="~/Captcha?bc=black" alt="Captcha" />

  <img src="~/Captcha?bc=random" alt="Captcha" />

• You can change the forecolor of the captcha by the code below either by writting the color name or the keyword random. (Default is random):

  <img src="~/Captcha?fc=green" alt="Captcha" />

• You can change type of the characters. num for numeric characters or mix for alphanumeric characters. (Default is mix):

  <img src="~/Captcha?t=num" alt="Captcha" />