As a web developer we know what is captcha is. It’s way to confirm users as they are human.Following is captcha definition per WikiPedia.

A CAPTCHA ( /ˈkæptʃə/) is a type of challenge-response test used in computing as an attempt to ensure that the response is generated by a person. The process usually involves one computer (a server) asking a user to complete a simple test which the computer is able to generate and grade. Because other computers are assumed to be unable to solve the CAPTCHA, any user entering a correct solution is presumed to be human. Thus, it is sometimes described as a reverse Turing test, because it is administered by a machine and targeted to a human, in contrast to the standard Turing test that is typically administered by a human and targeted to a machine. A common type of CAPTCHA requires the user to type letters or digits from a distorted image that appears on the screen.

You can find more details about that on following link.

http://en.wikipedia.org/wiki/CAPTCHA.

Google ReCaptcha Service:

Google provide Recaptcha service free of charge to confirm users whether they are human or computer. We can directly use the recaptcha service with there api. You have to create a private key for that and that key will validate domains against it. Even we can create the global key for all the keys. You can find more information about it from below link.

http://www.google.com/recaptcha/learnmore

ReCaptcha Web helpers in ASP.NET MVC 3:

As per I have also written in my previous post. ASP.NET Web helpers from Microsoft comes inbuilt with tools update. If you not installed it then you have to download NuGet package for it. You can refer my previous post for this.

Now we have all things ready its time to write ReCaptcha code in ASP.NET MVC. First we have create key for recaptcha service. I have created it via following link. It’s very easy.

https://www.google.com/recaptcha

Now let’s start coding. Recaptcha web helper renders a captcha control in your web form so you can validate this. Following is code which will render captcha control.
@ReCaptcha.GetHtml(theme: "red")
It's take four argument

1. Theme- theme specify the color and look for ReCaptcha control. You can have to put theme name over there
2. Language- You need to specify the captcha challenge language
3. TabIndex- Tab Index for this control
4. PublicKey- A unique public key which we have created for our domain.

Following is a code how to use above code in real time. I have updated standard logon control template for ASP.NET MVC.

@model CodeSimplifiedTest.Models.LogOnModel

@{
    ViewBag.Title = "Log On";
    ReCaptcha.PublicKey=@"6LedqMcSAAAAAJgiIjKlyzzV2czbGOPvij1tc39A";
}

<h2>Log On</h2>
<p>
    Please enter your user name and password. @Html.ActionLink("Register", "Register") if you don't have an account.
</p>

<script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script>
<script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>
<script src="@Url.Content("~/Scripts/jquery-1.5.1.min.js")" type="text/javascript"></script>
@Html.ValidationSummary(true, "Login was unsuccessful. Please correct the errors and try again.")

@using (Html.BeginForm()) {
    <div>
        <fieldset>
            <legend>Account Information</legend>

            <div class="editor-label">
                @Html.LabelFor(m => m.UserName)
            </div>
            <div class="editor-field">
                @Html.TextBoxFor(m => m.UserName)
                @Html.ValidationMessageFor(m => m.UserName)
            </div>

            <div class="editor-label">
                @Html.LabelFor(m => m.Password)
            </div>
            <div class="editor-field">
                @Html.PasswordFor(m => m.Password)
                @Html.ValidationMessageFor(m => m.Password)
            </div>

            <div class="editor-label">
                @Html.CheckBoxFor(m => m.RememberMe)
                @Html.LabelFor(m => m.RememberMe)
            </div>

            <p>
               @ReCaptcha.GetHtml(theme: "red")
            </p>
           
        </fieldset>
    </div>
}

As you can see in above code for recaptcha public key and Recaptcha.GetHtml part. Now its time to captcha validation in server side code in controller. As I have used standard logon template for this.I have modified Logon Action Result in Account controller like following.

[HttpPost]
public ActionResult LogOn(LogOnModel model, string returnUrl)
{
    if(!ReCaptcha.Validate(privateKey:"6LedqMcSAAAAAJgiIjKlyzzV2czbGOPvij1tc39A"))
    {
        return Content("Failed");
    }
  
    if (ModelState.IsValid)
    {
        if (Membership.ValidateUser(model.UserName, model.Password))
        {
            FormsAuthentication.SetAuthCookie(model.UserName, model.RememberMe);
            if (Url.IsLocalUrl(returnUrl) && returnUrl.Length > 1 && returnUrl.StartsWith("/")
                && !returnUrl.StartsWith("//") && !returnUrl.StartsWith("/\\"))
            {
                return Redirect(returnUrl);
            }
            else
            {
                return RedirectToAction("Index", "Home");
            }
        }
        else
        {
            ModelState.AddModelError("", "The user name or password provided is incorrect.");
        }
    }

    // If we got this far, something failed, redisplay form
    return View(model);
}

Here I have validated the captcha control with public key and if validation failed then it will sent failed message. Now it’s time to run that in browser and let’s see output.



That’s it. Its easy to integrate. Hope you like it..Stay tuned for more.. Till then Happy Programing..Namaste!!

I am exploring ASP.NET MVC3 and everyday I am learning something new. In today’s post I am going to explain how we can create chart with ASP.NET MVC3.

Chart is one of greatest way of expressing figures. We all need that functionality in any commercial application. I am still remembering old days with ASP.NET  where we have to use the third party controls for charts or we have to create it with the use of CSS and Server side controls. But now with ASP.NET MVC Helpers you can very easily create chart in few lines of code.

ASP.NET MVC Chart helper and other helpers comes inbuilt with the latest ASP.NET Tools update. If you don’t have ASP.NET MVC Chart helpers then you can find more information about it from here.

http://haacked.com/archive/2011/04/12/introducing-asp-net-mvc-3-tools-update.aspx

But still if you have not updated it then don’t worry about it. There is nuget package called “ASP.NET Webhelper Library”. You can add that package like following and still use same functionality.



Now once you have all set for reference. We can start working on coding part. So draw a chart I have taken simple example like number of records vs time take chart. This Chart Helper support there types of cjart.

1. Bar Chart
2. Pie Chart
3. Column Chart

In this example we are going to use Bar Chart. Following is code for that. I have create one simple action result called “DrawChart” which will return chart as PNG format.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Web.Helpers;

namespace CodeSimplifiedTest.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
        {
            ViewBag.Message = "Welcome to ASP.NET MVC!";

            return View();
        }

        public ActionResult About()
        {
            return View();
        }

        public ActionResult DrawChart()
        {
            var chart = new Chart(width: 300, height: 200)
                .AddSeries(
                            chartType: "bar",
                            xValue: new[] { "10 Records", "20 Records", "30 Records", "40 Records" },
                            yValues: new[] { "50", "60", "78", "80" })
                            .GetBytes("png");
            return File(chart, "image/bytes");
        }
    }
}

Here you can see that first I have included System.Web.Helper name space on top and then in DrawChart Action Result I have created chart variable where I have specified the height and width of chart and in add series method of it I have provided the chart type and x axis and y axis value. Now as we have to display it as image so for that I have used @URL.Action to point src to our Action Result DrawChart like following.

<img src="@Url.Action("DrawChart")" alt="Drawing chart with HTML Helper" />

Now let’s run this application in browser via pressing Ctrl+F5 and following is the output as expected.



That’s it. You can see its very to create any kind of chart with Chart Helpers in ASP.NET MVC 3. Hope you like it. Stay tuned for more.. Till then happy programming and Namaste!!