URL Rewrite

using System;

using System.IO;

using System.Threading;

using System.Web;



using Com.Website.Configuration;

using Com.Website.WebModel.Resource;

using Com.Website.DomainModel;



namespace Com.Website.HttpModule.UrlRewriter

{

    /// <summary>

    /// Url rewrite http module

    /// </summary>

    public class UrlRewriteHttpModule : IHttpModule

    {

        private UrlHelper urlHelper;

        private RewriteRuleCollection rewriteRuleList = new RewriteRuleCollection();



        public UrlRewriteHttpModule()

        {

            this.urlHelper = new UrlHelper();

        }



        #region IHttpModule Members



        public void Init(HttpApplication context)

        {

            context.BeginRequest += new EventHandler(OnBeginRequest);

        }



        public void Dispose()

        {



        }



        #endregion



        private void InitialSetting()

        {

            rewriteRuleList.Clear();

            foreach (RewriteSetting rewriteSetting in ConfigurationManager.UrlRewriterConfiguration.RewriteConfiguration.RewriteSettingCollection)

            {

                RewriteRule rewrite = null;

                string providerName = rewriteSetting.Provider;

                if (string.IsNullOrEmpty(providerName))

                {

                    rewrite = UrlRewrite.CreateRewriteRule();

                }

                else

                {

                    rewrite = UrlRewrite.CreateRewriteRule(providerName);

                }

                rewrite.Initialize(rewriteSetting);

                rewriteRuleList.Add(rewrite);

            }

        }



        private void OnBeginRequest(object sender, EventArgs e)

        {

            HttpApplication application = sender as HttpApplication;



            if (File.Exists(application.Request.PhysicalPath)) return;



            if (!(ConfigurationManager.BizConfiguration != null 

                    && ConfigurationManager.UrlRewriterConfiguration != null

                    && ConfigurationManager.UrlRewriterConfiguration.RewriteConfiguration != null

                    && ConfigurationManager.UrlRewriterConfiguration.RewriteConfiguration.RewriteSettingCollection != null))

                return;



            string pageName = string.Empty;

            if (HttpContext.Current != null && 

                HttpContext.Current.Request != null &&

                HttpContext.Current.Request.Url != null)

            {

                pageName = HttpContext.Current.Request.Url.AbsolutePath;

            }

            PageUrlAlias currentAlias = PageUrlAlias.InvalidUrl;

            if (!string.IsNullOrWhiteSpace(pageName))

            {

                currentAlias = ConfigurationManager.WebPageConfiguration.GetPageUrlAlias(pageName);

            }



            if (ConfigurationManager.UrlRewriterConfiguration.ExceptPage != null

                && ConfigurationManager.UrlRewriterConfiguration.ExceptPage.Pages != null

                && ConfigurationManager.UrlRewriterConfiguration.ExceptPage.Pages.Exists(d => d == currentAlias))

            {

                return;

            }



            InitialSetting();

            string requestUrl = application.Request.RawUrl;

            string requestQuerystring = string.Empty;

            string virtualUrl = requestUrl;

            int pos = requestUrl.IndexOf('?');

            if (pos >= 0)

            {

                requestQuerystring = requestUrl.Substring(pos + 1);

                virtualUrl = requestUrl.Substring(0, pos);

            }

            virtualUrl = virtualUrl.TrimEnd('/');



            RewriteRule rewriteRule = rewriteRuleList.Find(new Predicate<RewriteRule>(delegate(RewriteRule rule) { return rule.IsRewrite(virtualUrl); }));

            if (rewriteRule == null) return;



            string destinationUrl = rewriteRule.RewriteUrl(virtualUrl);

            destinationUrl = urlHelper.JoinUrlParameter(urlHelper.HandleRootOperator(destinationUrl), requestQuerystring);



            HttpContext.Current.RewritePath(destinationUrl);

        }

    }

}