/BlogEngine/BlogEngine.NET/App_Code/Extensions/SimpleCaptcha/SimpleCaptchaControl.cs

// Inspired by and interface heavily borrowed from Filip Stanek's ( http://www.bloodforge.com ) Recaptcha extension for blogengine.net

// SimpleCaptcha created by Aaron Stannard (http://www.aaronstannard.com )



namespace App_Code.Controls

{

    using System;

    using System.Web.UI;

    using System.Web.UI.WebControls;

    using BlogEngine.Core;

    using BlogEngine.Core.Web.Extensions;



    /// <summary>

    /// This is the IValidator control that gets embedded on the comment form if the SimpleCaptcha extension is enabled.

    /// </summary>

    public class SimpleCaptchaControl : WebControl, IValidator

    {

        #region Constants and Fields



        /// <summary>

        /// The simple captcha answer field.

        /// </summary>

        private const string SimpleCaptchaAnswerField = "simpleCaptchaValue";



        /// <summary>

        /// The error message.

        /// </summary>

        private string errorMessage;



        /// <summary>

        /// Whether is valid.

        /// </summary>

        private bool valid;



        /// <summary>

        /// The simple captcha answer.

        /// </summary>

        private string simpleCaptchaAnswer;



        /// <summary>

        /// The simple captcha label.

        /// </summary>

        private string simpleCaptchaLabel;



        /// <summary>

        /// The skip simple captcha.

        /// </summary>

        private bool skipSimpleCaptcha = true;



        #endregion



        #region Properties



        /// <summary>

        ///     Gets or sets ErrorMessage.

        /// </summary>

        public string ErrorMessage

        {

            get

            {

                return this.errorMessage ?? Resources.labels.incorrectSimpleCaptcha;

            }



            set

            {

                this.errorMessage = value;

            }

        }



        /// <summary>

        ///     Gets or sets a value indicating whether valid.

        /// </summary>

        public bool IsValid

        {

            get

            {

                return this.valid;

            }



            set

            {

            }

        }



        /// <summary>

        ///     Gets a value indicating whether the control has been enabled via the Extension Manager

        /// </summary>

        public bool SimpleCaptchaEnabled

        {

            get

            {

                var captchaExtension = ExtensionManager.GetExtension("SimpleCaptcha");

                return captchaExtension.Enabled;

            }

        }



        /// <summary>

        ///     Gets a value indicating whether the recaptcha needs to be displayed for the current user

        /// </summary>

        public bool SimpleCaptchaNecessary

        {

            get

            {

                var settings = ExtensionManager.GetSettings("SimpleCaptcha");

                return !Security.IsAuthenticated ||

                       Convert.ToBoolean(settings.GetSingleValue("ShowForAuthenticatedUsers"));

            }

        }



        #endregion



        #region Public Methods



        /// <summary>

        /// The validate.

        /// </summary>

        /// <param name="simpleCaptchaChallenge">

        /// The simple captcha challenge.

        /// </param>

        public void Validate(string simpleCaptchaChallenge)

        {

            this.valid = this.skipSimpleCaptcha || this.simpleCaptchaAnswer.Equals(simpleCaptchaChallenge);

        }



        #endregion



        #region Implemented Interfaces



        #region IValidator



        /// <summary>

        /// The validate.

        /// </summary>

        public void Validate()

        {

            var simpleCaptchaChallenge = this.Context.Request.Form[SimpleCaptchaAnswerField];

            this.Validate(simpleCaptchaChallenge);

        }



        #endregion



        #endregion



        #region Methods



        /// <summary>

        /// Raises the <see cref="E:System.Web.UI.Control.Init"/> event.

        /// </summary>

        /// <param name="e">

        /// An <see cref="T:System.EventArgs"/> object that contains the event data.

        /// </param>

        protected override void OnInit(EventArgs e)

        {

            base.OnInit(e);



            var settings = ExtensionManager.GetSettings("SimpleCaptcha");

            this.simpleCaptchaAnswer = settings.GetSingleValue("CaptchaAnswer");

            this.simpleCaptchaLabel = settings.GetSingleValue("CaptchaLabel");



            if (this.SimpleCaptchaEnabled && this.SimpleCaptchaNecessary)

            {

                this.skipSimpleCaptcha = false;

            }



            if (String.IsNullOrEmpty(this.simpleCaptchaAnswer) || String.IsNullOrEmpty(this.simpleCaptchaLabel))

            {

                throw new ApplicationException(

                    "SimpleCaptcha needs to be configured with an appropriate captcha label and a captcha value.");

            }

        }



        /// <summary>

        /// Renders the control to the specified HTML writer.

        /// </summary>

        /// <param name="writer">

        /// The <see cref="T:System.Web.UI.HtmlTextWriter"/> object that receives the control content.

        /// </param>

        protected override void Render(HtmlTextWriter writer)

        {

            if (!this.skipSimpleCaptcha)

            {

                this.RenderContents(writer);

            }

        }



        /// <summary>

        /// Renders the contents.

        /// </summary>

        /// <param name="output">

        /// The output.

        /// </param>

        protected override void RenderContents(HtmlTextWriter output)

        {

            output.RenderBeginTag(HtmlTextWriterTag.P);

            output.AddAttribute(HtmlTextWriterAttribute.For, SimpleCaptchaAnswerField);

            output.RenderBeginTag(HtmlTextWriterTag.Label);

            output.Write(this.simpleCaptchaLabel);

            output.RenderEndTag();



            output.AddAttribute(HtmlTextWriterAttribute.Id, SimpleCaptchaAnswerField);

            output.AddAttribute(HtmlTextWriterAttribute.Name, SimpleCaptchaAnswerField);

            output.AddAttribute(HtmlTextWriterAttribute.Type, "text");

            output.AddAttribute(HtmlTextWriterAttribute.Tabindex, this.TabIndex.ToString());

            output.AddAttribute(HtmlTextWriterAttribute.Maxlength, Convert.ToString(SimpleCaptcha.MaxCaptchaLength));

            output.AddAttribute(HtmlTextWriterAttribute.Value, string.Empty);

            output.RenderBeginTag(HtmlTextWriterTag.Input);

            output.RenderEndTag();



            output.AddAttribute(HtmlTextWriterAttribute.Id, "spnSimpleCaptchaIncorrect");

            output.AddStyleAttribute(HtmlTextWriterStyle.Display, "none");

            output.AddStyleAttribute(HtmlTextWriterStyle.Color, "Red");

            output.RenderBeginTag(HtmlTextWriterTag.Span);

            output.WriteLine(this.ErrorMessage);

            output.RenderEndTag();

            output.RenderEndTag();

        }



        #endregion

    }

}