RssDocument.cs

using System;
using System.Xml;
using Waher.Content.Xml;
using Waher.Runtime.Collections;
using Waher.Runtime.Inventory;

namespace Waher.Content.Rss
{
	/// <summary>
	/// Contains information from an RSS feed.
	/// </summary>
	public class RssDocument
	{
		private readonly XmlDocument xml;

		/// <summary>
		/// Contains information from an RSS feed.
		/// </summary>
		/// <param name="Xml">RSS XML document.</param>
		/// <param name="BaseUri">Base Uri</param>
		public RssDocument(XmlDocument Xml, Uri BaseUri)
		{
			if (Xml is null)
				throw new ArgumentNullException(nameof(Xml));

			if (Xml.DocumentElement is null)
				throw new ArgumentException("Missing XML.", nameof(Xml));

			if (Xml.DocumentElement.LocalName != "rss")
				throw new ArgumentException("Not an RSS document.", nameof(Xml));

			this.xml = Xml;
			this.Version = XML.Attribute(Xml.DocumentElement, "version", 0.0);

			ChunkedList<RssChannel> Channels = new ChunkedList<RssChannel>();
			ChunkedList<RssWarning> Warnings = new ChunkedList<RssWarning>();
			ChunkedList<IRssExtension> Extensions = new ChunkedList<IRssExtension>();

			foreach (XmlNode N in Xml.DocumentElement.ChildNodes)
			{
				if (!(N is XmlElement E))
					continue;

				if (E.NamespaceURI == Xml.NamespaceURI)
				{
					switch (E.LocalName)
					{
						case "channel":
							RssChannel Channel = new RssChannel(E, BaseUri);
							Channels.Add(Channel);
							Warnings.AddRange(Channel.Warnings);
							break;

						default:
							Warnings.Add(new RssWarning(E));
							break;
					}
				}
				else
				{
					IRssExtension Extension = Types.FindBest<IRssExtension, XmlElement>(E);
					if (Extension is null)
						Warnings.Add(new RssWarning(E));
					else
						Extensions.Add(Extension.Create(E, BaseUri));
				}
			}

			this.Channels = Channels.ToArray();
			this.Warnings = Warnings.ToArray();
			this.Extensions = Extensions.ToArray();
		}

		/// <summary>
		/// RSS XML document.
		/// </summary>
		public XmlDocument Xml => this.xml;

		/// <summary>
		/// Version of RSS document.
		/// </summary>
		public double Version { get; }

		/// <summary>
		/// Channels
		/// </summary>
		public RssChannel[] Channels { get; }

		/// <summary>
		/// Any warning messages created during parsing.
		/// </summary>
		public RssWarning[] Warnings { get; }

		/// <summary>
		/// Extensions
		/// </summary>
		public IRssExtension[] Extensions { get; } = null;
	}
}