/BlogEngine/DotNetSlave.BusinessLogic/Web/HttpHandlers/BlogMLExportHandler.cs

namespace BlogEngine.Core.Web.HttpHandlers

{

    using System;

    using System.Globalization;

    using System.Linq;

    using System.Text;

    using System.Threading;

    using System.Web;

    using System.Web.Security;

    using System.Xml;



    /// <summary>

    /// Exports all posts to the BlogML xml format.

    /// </summary>

    public class BlogMLExportHandler : IHttpHandler

    {

        #region Properties



        /// <summary>

        ///     Gets a value indicating whether another request can use the <see cref = "T:System.Web.IHttpHandler"></see> instance.

        /// </summary>

        /// <value></value>

        /// <returns>true if the <see cref = "T:System.Web.IHttpHandler"></see> instance is reusable; otherwise, false.</returns>

        public bool IsReusable

        {

            get

            {

                return false;

            }

        }



        #endregion



        #region Implemented Interfaces



        #region IHttpHandler



        /// <summary>

        /// Enables processing of HTTP Web requests by a custom HttpHandler that implements the <see cref="T:System.Web.IHttpHandler"></see> interface.

        /// </summary>

        /// <param name="context">

        /// An <see cref="T:System.Web.HttpContext"></see> object that provides references to the intrinsic server 

        ///     objects (for example, Request, Response, Session, and Server) used to service HTTP requests.

        /// </param>

        public void ProcessRequest(HttpContext context)

        {

            if (Security.IsAdministrator)

            {

                context.Response.ContentType = "text/xml";

                context.Response.AppendHeader("Content-Disposition", "attachment; filename=BlogML.xml");

                WriteXml(context);

            }

            else

            {

                context.Response.StatusCode = 403;

            }

        }



        #endregion



        #endregion



        #region Methods



        /// <summary>

        /// Add authors.

        /// </summary>

        /// <param name="writer">

        /// The writer.

        /// </param>

        private static void AddAuthors(XmlWriter writer)

        {

            writer.WriteStartElement("authors");



            foreach (MembershipUser user in Membership.GetAllUsers())

            {

                writer.WriteStartElement("author");



                writer.WriteAttributeString("id", user.UserName);

                writer.WriteAttributeString(

                    "date-created", user.CreationDate.ToString("yyyy-MM-ddTHH:mm:ss", CultureInfo.InvariantCulture));

                writer.WriteAttributeString(

                    "date-modified", user.CreationDate.ToString("yyyy-MM-ddTHH:mm:ss", CultureInfo.InvariantCulture));

                writer.WriteAttributeString("approved", "true");

                writer.WriteAttributeString("email", user.Email);



                writer.WriteStartElement("title");

                writer.WriteAttributeString("type", "text");

                writer.WriteCData(user.UserName);

                writer.WriteEndElement();



                writer.WriteEndElement();

            }



            writer.WriteEndElement();

        }



        /// <summary>

        /// Add categories.

        /// </summary>

        /// <param name="writer">

        /// The writer.

        /// </param>

        private static void AddCategories(XmlWriter writer)

        {

            writer.WriteStartElement("categories");



            foreach (var category in Category.Categories)

            {

                writer.WriteStartElement("category");



                writer.WriteAttributeString("id", category.Id.ToString());

                writer.WriteAttributeString(

                    "date-created", category.DateCreated.ToString("yyyy-MM-ddTHH:mm:ss", CultureInfo.InvariantCulture));

                writer.WriteAttributeString(

                    "date-modified", category.DateModified.ToString("yyyy-MM-ddTHH:mm:ss", CultureInfo.InvariantCulture));

                writer.WriteAttributeString("approved", "true");

                writer.WriteAttributeString("parentref", "0");



                if (!String.IsNullOrEmpty(category.Description))

                {

                    writer.WriteAttributeString("description", category.Description);

                }



                writer.WriteStartElement("title");

                writer.WriteAttributeString("type", "text");

                writer.WriteCData(category.Title);

                writer.WriteEndElement();



                writer.WriteEndElement();

            }



            writer.WriteEndElement();

        }



        /// <summary>

        /// Add extended properties.

        /// </summary>

        /// <param name="writer">

        /// The writer.

        /// </param>

        private static void AddExtendedProperties(XmlWriter writer)

        {

            writer.WriteStartElement("extended-properties");



            writer.WriteStartElement("property");

            writer.WriteAttributeString("name", "CommentModeration");

            writer.WriteAttributeString("value", "Anonymous");

            writer.WriteEndElement();



            writer.WriteStartElement("property");

            writer.WriteAttributeString("name", "SendTrackback");

            writer.WriteAttributeString("value", BlogSettings.Instance.EnableTrackBackSend ? "Yes" : "No");

            writer.WriteEndElement();



            writer.WriteEndElement();

        }



        /// <summary>

        /// Add post author.

        /// </summary>

        /// <param name="writer">

        /// The writer.

        /// </param>

        /// <param name="post">

        /// The post to add the author on.

        /// </param>

        private static void AddPostAuthor(XmlWriter writer, Post post)

        {

            writer.WriteStartElement("authors");

            writer.WriteStartElement("author");

            writer.WriteAttributeString("ref", post.Author);

            writer.WriteEndElement();

            writer.WriteEndElement();

        }



        /// <summary>

        /// Add post categories.

        /// </summary>

        /// <param name="writer">

        /// The writer.

        /// </param>

        /// <param name="post">

        /// The post to add categories to.

        /// </param>

        private static void AddPostCategories(XmlWriter writer, Post post)

        {

            if (post.Categories.Count == 0)

            {

                return;

            }



            writer.WriteStartElement("categories");

            foreach (var category in post.Categories)

            {

                writer.WriteStartElement("category");

                writer.WriteAttributeString("ref", category.Id.ToString());

                writer.WriteEndElement();

            }



            writer.WriteEndElement();

        }



        /// <summary>

        /// Add post comments.

        /// </summary>

        /// <param name="writer">

        /// The writer.

        /// </param>

        /// <param name="post">

        /// The post to add comments to.

        /// </param>

        private static void AddPostComments(XmlWriter writer, Post post)

        {

            if (post.Comments.Count == 0)

            {

                return;

            }



            writer.WriteStartElement("comments");

            foreach (var comment in

                post.Comments.Where(comment => comment.Email != "trackback" && comment.Email != "pingback"))

            {

                writer.WriteStartElement("comment");

                writer.WriteAttributeString("id", comment.Id.ToString());

                writer.WriteAttributeString("parentid", comment.ParentId.ToString());

                writer.WriteAttributeString(

                    "date-created", comment.DateCreated.ToString("yyyy-MM-ddTHH:mm:ss", CultureInfo.InvariantCulture));

                writer.WriteAttributeString(

                    "date-modified", comment.DateCreated.ToString("yyyy-MM-ddTHH:mm:ss", CultureInfo.InvariantCulture));

                writer.WriteAttributeString("approved", comment.IsApproved.ToString().ToLowerInvariant());

                writer.WriteAttributeString("user-name", comment.Author);

                writer.WriteAttributeString("user-email", comment.Email);

                writer.WriteAttributeString("user-ip", comment.IP);



                if (comment.Website != null)

                {

                    writer.WriteAttributeString("user-url", comment.Website.ToString());

                }

                else

                {

                    writer.WriteAttributeString("user-url", string.Empty);

                }



                writer.WriteStartElement("title");

                writer.WriteAttributeString("type", "text");

                writer.WriteCData("re: " + post.Title);

                writer.WriteEndElement();



                writer.WriteStartElement("content");

                writer.WriteAttributeString("type", "text");

                writer.WriteCData(comment.Content);

                writer.WriteEndElement();



                writer.WriteEndElement();

            }



            writer.WriteEndElement();

        }



        /// <summary>

        /// Add post content.

        /// </summary>

        /// <param name="writer">

        /// The writer.

        /// </param>

        /// <param name="post">

        /// The post to add content to.

        /// </param>

        private static void AddPostContent(XmlWriter writer, Post post)

        {

            writer.WriteStartElement("content");

            writer.WriteAttributeString("type", "text");

            writer.WriteCData(post.Content);

            writer.WriteEndElement();

        }



        /// <summary>

        /// Adds the post excerpt.

        /// </summary>

        /// <param name="writer">The writer.</param>

        /// <param name="post">The post to add the excerpt to.</param>

        private static void AddPostExcerpt(XmlWriter writer, Post post)

        {

            if (String.IsNullOrEmpty(post.Description))

            {

                return;

            }



            writer.WriteStartElement("excerpt");

            writer.WriteAttributeString("type", "text");

            writer.WriteCData(post.Description);

            writer.WriteEndElement();

        }



        /// <summary>

        /// The post-name element contains the same as the title.

        /// </summary>

        /// <param name="writer">

        /// The writer.

        /// </param>

        /// <param name="post">

        /// The post to add a name to.

        /// </param>

        private static void AddPostName(XmlWriter writer, Post post)

        {

            writer.WriteStartElement("post-name");

            writer.WriteAttributeString("type", "text");

            writer.WriteCData(post.Title);

            writer.WriteEndElement();

        }



        /// <summary>

        /// Adds the post tags.

        /// </summary>

        /// <param name="writer">The writer.</param>

        /// <param name="post">The post to add tags to.</param>

        private static void AddPostTags(XmlWriter writer, Post post)

        {

            if (post.Tags.Count == 0)

            {

                return;

            }



            writer.WriteStartElement("tags");

            foreach (var tag in post.Tags)

            {

                writer.WriteStartElement("tag");

                writer.WriteAttributeString("ref", tag);

                writer.WriteEndElement();

            }



            writer.WriteEndElement();

        }



        /// <summary>

        /// Adds the post title.

        /// </summary>

        /// <param name="writer">The writer.</param>

        /// <param name="post">The post to add the title to.</param>

        private static void AddPostTitle(XmlWriter writer, Post post)

        {

            writer.WriteStartElement("title");

            writer.WriteAttributeString("type", "text");

            writer.WriteCData(post.Title);

            writer.WriteEndElement();

        }



        /// <summary>

        /// Adds the post trackbacks.

        /// </summary>

        /// <param name="writer">The writer.</param>

        /// <param name="post">The post to add trackbacks for.</param>

        private static void AddPostTrackbacks(XmlWriter writer, Post post)

        {

            if (post.Comments.Count == 0)

            {

                return;

            }



            writer.WriteStartElement("trackbacks");

            foreach (var comment in

                post.Comments.Where(comment => comment.Email == "trackback" || comment.Email == "pingback"))

            {

                writer.WriteStartElement("trackback");

                writer.WriteAttributeString("id", comment.Id.ToString());

                writer.WriteAttributeString(

                    "date-created", comment.DateCreated.ToString("yyyy-MM-ddTHH:mm:ss", CultureInfo.InvariantCulture));

                writer.WriteAttributeString(

                    "date-modified", comment.DateCreated.ToString("yyyy-MM-ddTHH:mm:ss", CultureInfo.InvariantCulture));

                writer.WriteAttributeString("approved", comment.IsApproved.ToString().ToLowerInvariant());



                if (comment.Website != null)

                {

                    writer.WriteAttributeString("url", comment.Website.ToString());

                }



                writer.WriteStartElement("title");

                writer.WriteAttributeString("type", "text");

                writer.WriteCData(comment.Content);

                writer.WriteEndElement();



                writer.WriteEndElement();

            }



            writer.WriteEndElement();

        }



        /// <summary>

        /// Adds the posts.

        /// </summary>

        /// <param name="writer">The writer.</param>

        private static void AddPosts(XmlWriter writer)

        {

            writer.WriteStartElement("posts");



            foreach (var post in Post.Posts)

            {

                writer.WriteStartElement("post");



                writer.WriteAttributeString("id", post.Id.ToString());

                writer.WriteAttributeString(

                    "date-created", post.DateCreated.ToString("yyyy-MM-ddTHH:mm:ss", CultureInfo.InvariantCulture));

                writer.WriteAttributeString(

                    "date-modified", post.DateModified.ToString("yyyy-MM-ddTHH:mm:ss", CultureInfo.InvariantCulture));

                writer.WriteAttributeString("approved", "true");

                writer.WriteAttributeString("post-url", post.RelativeLink);

                writer.WriteAttributeString("type", "normal");

                writer.WriteAttributeString(

                    "hasexcerpt", (!string.IsNullOrEmpty(post.Description)).ToString().ToLowerInvariant());

                writer.WriteAttributeString("views", "0");

                writer.WriteAttributeString("is-published", post.IsPublished.ToString());



                AddPostTitle(writer, post);

                AddPostContent(writer, post);

                AddPostName(writer, post);

                AddPostExcerpt(writer, post);

                AddPostAuthor(writer, post);

                AddPostCategories(writer, post);

                AddPostTags(writer, post);

                AddPostComments(writer, post);

                AddPostTrackbacks(writer, post);



                writer.WriteEndElement();

            }



            writer.WriteEndElement();

        }



        /// <summary>

        /// Adds the sub title.

        /// </summary>

        /// <param name="writer">The writer.</param>

        private static void AddSubTitle(XmlWriter writer)

        {

            writer.WriteStartElement("sub-title");

            writer.WriteAttributeString("type", "text");

            writer.WriteCData(BlogSettings.Instance.Description);

            writer.WriteEndElement();

        }



        /// <summary>

        /// Adds the title.

        /// </summary>

        /// <param name="writer">The writer.</param>

        private static void AddTitle(XmlWriter writer)

        {

            writer.WriteStartElement("title");

            writer.WriteAttributeString("type", "text");

            writer.WriteCData(BlogSettings.Instance.Name);

            writer.WriteEndElement();

        }



        /// <summary>

        /// Writes the BlogML to the output stream.

        /// </summary>

        /// <param name="context">

        /// The context.

        /// </param>

        private static void WriteXml(HttpContext context)

        {

            var settings = new XmlWriterSettings { Encoding = Encoding.UTF8, Indent = true };



            using (var writer = XmlWriter.Create(context.Response.OutputStream, settings))

            {

                writer.WriteStartElement("blog", "http://www.blogml.com/2006/09/BlogML");

                writer.WriteAttributeString("root-url", Utils.RelativeWebRoot);

                writer.WriteAttributeString(

                    "date-created", DateTime.Now.ToString("yyyy-MM-ddTHH:mm:ss", CultureInfo.InvariantCulture));

                writer.WriteAttributeString("xmlns", "xs", null, "http://www.w3.org/2001/XMLSchema");



                AddTitle(writer);

                AddSubTitle(writer);

                AddAuthors(writer);

                AddExtendedProperties(writer);

                AddCategories(writer);

                AddPosts(writer);



                writer.WriteEndElement();

            }

        }



        #endregion

    }

}