//controller function to generate image
//returns image file (through url.action in img src attribute)
public ActionResult GetCaptcha(string prefix, bool noisy = true)
{
var rand = new Random((int)DateTime.Now.Ticks);
//generate new question
int a = rand.Next(10, 99);
int b = rand.Next(0, 9);
var captcha = string.Format("{0} + {1} = ?", a, b);
//store answer
Session["Captcha" + prefix] = a + b;
//image stream
FileContentResult img = null;
try
{
img = this.File(CaptchaHelper.GenerateCaptchaImg(captcha, true), "image/Jpeg");
}
catch (Exception e)
{
Logger.Error(e);
}
return(img);
}
