OpmlProvider.cs :  » Bloggers » SubText » Subtext » Web » Admin » C# / CSharp Open Source

#region Disclaimer/Info

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// weblog system.
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// This project is licensed under the BSD license.  See the License.txt file for more information.
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#endregion

using System;
using System.Collections.Generic;
using System.IO;
using System.Xml;
using System.Xml.Serialization;
using System.Xml.XPath;
using Subtext.Framework.Components;

namespace Subtext.Web.Admin{
    public static class OpmlProvider
    {
        public static IXPathNavigable Export(ICollection<Link> items)
        {
            var doc = new XmlDocument();
            XmlDeclaration declaration = doc.CreateXmlDeclaration("1.0", "utf-8", null);
            doc.AppendChild(declaration);

            XmlNode rootNode = doc.CreateElement("opml");
            doc.AppendChild(rootNode);

            XmlNode headNode = doc.CreateElement("head");
            rootNode.AppendChild(headNode);

            XmlNode bodyNode = doc.CreateElement("body");
            rootNode.AppendChild(bodyNode);

            foreach(Link currentItem in items)
            {
                XmlNode outline = doc.CreateElement("outline");

                XmlAttribute title = doc.CreateAttribute("title");
                title.Value = currentItem.Title;
                outline.Attributes.Append(title);

                XmlAttribute description = doc.CreateAttribute("description");
                description.Value = currentItem.Title;
                outline.Attributes.Append(description);

                XmlAttribute htmlurl = doc.CreateAttribute("htmlurl");
                htmlurl.Value = currentItem.Url;
                outline.Attributes.Append(htmlurl);

                XmlAttribute xmlurl = doc.CreateAttribute("xmlurl");
                xmlurl.Value = currentItem.Rss;
                outline.Attributes.Append(xmlurl);

                bodyNode.AppendChild(outline);
            }

            return doc;

            //doc.LoadXml(sw.ToString());
            //return doc.CreateNavigator();
        }

        public static void WriteOpmlItem(OpmlItem item, XmlWriter writer)
        {
            item.RenderOpml(writer);

            foreach(OpmlItem childItem in item.ChildItems)
            {
                WriteOpmlItem(childItem, writer);
            }
        }

        public static OpmlItemCollection Import(Stream fileStream)
        {
            var _currentBatch = new OpmlItemCollection();

            XmlReader reader = new XmlTextReader(fileStream);
            var doc = new XPathDocument(reader);
            XPathNavigator nav = doc.CreateNavigator();

            XPathNodeIterator outlineItems = nav.Select("/opml/body/outline");

            while(outlineItems.MoveNext())
            {
                _currentBatch.AddRange(DeserializeItem(outlineItems.Current));
            }

            return _currentBatch;
        }

        public static IEnumerable<OpmlItem> DeserializeItem(XPathNavigator nav)
        {
            var items = new List<OpmlItem>();

            if(nav.HasAttributes)
            {
                string title = nav.GetAttribute("title", "");
                if(String.IsNullOrEmpty(title))
                {
                    title = nav.GetAttribute("text", "");
                }

                string htmlUrl = nav.GetAttribute("htmlurl", "");
                if(String.IsNullOrEmpty(htmlUrl))
                {
                    htmlUrl = nav.GetAttribute("htmlUrl", "");
                }

                string xmlUrl = nav.GetAttribute("xmlurl", "");
                if(String.IsNullOrEmpty(xmlUrl))
                {
                    xmlUrl = nav.GetAttribute("xmlUrl", "");
                }

                OpmlItem currentItem = null;
                string description = nav.GetAttribute("description", "");
                if(!String.IsNullOrEmpty(title) && !String.IsNullOrEmpty(htmlUrl))
                {
                    currentItem = new OpmlItem(title, description, xmlUrl, htmlUrl);
                }

                if(null != currentItem)
                {
                    items.Add(currentItem);
                }
            }

            if(nav.HasChildren)
            {
                XPathNodeIterator childItems = nav.SelectChildren("outline", "");
                while(childItems.MoveNext())
                {
                    IEnumerable<OpmlItem> children = DeserializeItem(childItems.Current);
                    if(null != children)
                    {
                        items.InsertRange(items.Count, children);
                    }
                }
            }

            return items;
        }
    }

    [Serializable]
    [XmlRoot(ElementName = "outline", IsNullable = true)]
    public class OpmlItem
    {
        private OpmlItemCollection _childItems;
        private string _description;
        private string _htmlurl;
        private string _title;
        private string _xmlurl;

        public OpmlItem()
        {
            _childItems = new OpmlItemCollection();
        }

        public OpmlItem(string title, string description, string xmlUrl, string htmlUrl)
            : this()
        {
            _title = title;
            _description = description;
            _xmlurl = xmlUrl;
            _htmlurl = htmlUrl;
        }

        [XmlAttribute("title")]
        public string Title
        {
            get { return _title; }
            set { _title = value; }
        }

        [XmlAttribute("description")]
        public string Description
        {
            get { return _description; }
            set { _description = value; }
        }

        [XmlAttribute("xmlurl")]
        public string XmlUrl
        {
            get { return _xmlurl; }
            set { _xmlurl = value; }
        }

        [XmlAttribute("htmlurl")]
        public string HtmlUrl
        {
            get { return _htmlurl; }
            set { _htmlurl = value; }
        }

        public OpmlItemCollection ChildItems
        {
            get { return _childItems; }
            set { _childItems = value; }
        }

        internal void RenderOpml(XmlWriter writer)
        {
            writer.WriteStartElement("outline");
            writer.WriteAttributeString("title", Title);
            writer.WriteAttributeString("description", Description);
            writer.WriteAttributeString("htmlurl", HtmlUrl);
            writer.WriteAttributeString("xmlurl", XmlUrl);
            writer.WriteEndElement();
        }
    }
}