BlogRequestModule.cs :  » Bloggers » SubText » Subtext » Framework » Web » HttpModules » C# / CSharp Open Source

#region Disclaimer/Info

///////////////////////////////////////////////////////////////////////////////////////////////////
// Subtext WebLog
// 
// Subtext is an open source weblog system that is a fork of the .TEXT
// weblog system.
//
// For updated news and information please visit http://subtextproject.com/
// Subtext is hosted at Google Code at http://code.google.com/p/subtext/
// The development mailing list is at subtext@googlegroups.com 
//
// This project is licensed under the BSD license.  See the License.txt file for more information.
///////////////////////////////////////////////////////////////////////////////////////////////////

#endregion

using System;
using System.Web;
using Subtext.Framework.Providers;
using Subtext.Framework.Services;

namespace Subtext.Framework.Web.HttpModules{
    /// <summary>
    /// Examines incoming http requests and adds Subtext specific as well as blog 
    /// specific information to the context.
    /// </summary>
    public class BlogRequestModule : IHttpModule
    {
        public BlogRequestModule()
            : this(new BlogLookupService(ObjectProvider.Instance(), HostInfo.Instance))
        {
        }

        public BlogRequestModule(IBlogLookupService blogLookup)
        {
            BlogLookup = blogLookup;
        }

        protected IBlogLookupService BlogLookup { get; private set; }

        /// <summary>
        /// Initializes a module and prepares it to handle
        /// requests.
        /// </summary>
        /// <param name="context">An <see cref="T:System.Web.HttpApplication"/> that provides access to the methods, properties, and events common to all application objects within an ASP.NET application</param>
        public void Init(HttpApplication context)
        {
            context.BeginRequest += MapUrlToBlogStatus;
        }

        /// <summary>
        /// Disposes of the resources (other than memory) used by the
        /// module that implements <see langword="IHttpModule."/>
        /// </summary>
        public void Dispose()
        {
            //Do Nothing.
        }

        /// <summary>
        /// Maps the incoming URL to the corresponding blog. If no blog matches, then 
        /// makes sure any host application settings are still set.
        /// </summary>
        /// <param name="sender">The sender.</param>
        /// <param name="e">The <see cref="System.EventArgs"/> instance containing the event data.</param>
        private void MapUrlToBlogStatus(object sender, EventArgs e)
        {
            BlogRequest.Current = ConvertRequestToBlogRequest(new HttpContextWrapper(HttpContext.Current));
        }

        public BlogRequest ConvertRequestToBlogRequest(HttpContextBase httpContext)
        {
            string redirectUrl = httpContext.Request.GetFileNotFoundRedirectUrl(HttpRuntime.UsingIntegratedPipeline);
            if(!String.IsNullOrEmpty(redirectUrl))
            {
                httpContext.Response.Redirect(redirectUrl);
            }

            // REVIEW: Maybe the BlogLookup.Lookup should take in an HttpContextBase 
            // and return the BlogRequest as part of the result.
            var blogRequest = new BlogRequest(httpContext.Request);
            if(blogRequest.BlogNotRequired)
            {
                return blogRequest;
            }
            BlogLookupResult result = BlogLookup.Lookup(blogRequest);

            if(result == null)
            {
                if(blogRequest.RequestLocation != RequestLocation.LoginPage)
                {
                    httpContext.Response.Redirect("~/install/BlogNotConfiguredError.aspx", true);
                }
                return blogRequest;
            }

            if(result.Blog == null && result.AlternateUrl != null)
            {
                httpContext.Response.RedirectPermanent(result.AlternateUrl.ToString());
                return null;
            }

            if(result.Blog != null && !result.Blog.IsActive && blogRequest.RequestLocation == RequestLocation.Blog)
            {
                httpContext.Response.Redirect("~/SystemMessages/BlogNotActive.aspx", true);
                return null;
            }

            blogRequest.Blog = result.Blog;
            return blogRequest;
        }
    }
}