RssChannel.cs

using System;
using System.Collections.Generic;
using System.Xml;
using Waher.Runtime.Inventory;
 
namespace Waher.Content.Rss
{
    public class RssChannel
    {
        public RssChannel(XmlElement Xml, Uri BaseUri)
        {
            if (Xml is null)
                throw new ArgumentNullException(nameof(Xml));
 
            List<RssWarning> Warnings = new List<RssWarning>();
            List<RssItem> Items = new List<RssItem>();
            List<RssCategory> Categories = new List<RssCategory>();
            List<IRssExtension> Extensions = new List<IRssExtension>();
 
            foreach (XmlNode N in Xml.ChildNodes)
            {
                if (!(N is XmlElement E))
                    continue;
 
                if (E.NamespaceURI == Xml.NamespaceURI)
                {
                    switch (E.LocalName)
                    {
                        case "title":
                            this.Title = E.InnerText;
                            break;
 
                        case "link":
                            if (Uri.TryCreate(BaseUri, E.InnerText, out Uri Link))
                                this.Link = Link;
                            else
                                Warnings.Add(new RssWarning(E, "Invalid URI: " + E.InnerText));
                            break;
 
                        case "description":
                            this.Description = E.InnerText;
                            break;
 
                        case "language":
                            this.Language = E.InnerText;
                            break;
 
                        case "copyright":
                            this.Copyright = E.InnerText;
                            break;
 
                        case "managingEditor":
                            this.ManagingEditor = E.InnerText;
                            break;
 
                        case "webMaster":
                            this.WebMaster = E.InnerText;
                            break;
 
                        case "pubDate":
                            if (CommonTypes.TryParseRfc822(E.InnerText, out DateTimeOffset PubDate))
                                this.PublicationDate = PubDate;
                            else
                                Warnings.Add(new RssWarning(E, "Unable to parse publication date: " + E.InnerText));
                            break;
 
                        case "lastBuildDate":
                            if (CommonTypes.TryParseRfc822(E.InnerText, out DateTimeOffset LastBuildDate))
                                this.LastBuildDate = LastBuildDate;
                            else
                                Warnings.Add(new RssWarning(E, "Unable to parse last build date: " + E.InnerText));
                            break;
 
                        case "category":
                            RssCategory Category = new RssCategory(E, BaseUri);
                            Warnings.AddRange(Category.Warnings);
                            Categories.Add(Category);
                            break;
 
                        case "generator":
                            this.Generator = E.InnerText;
                            break;
 
                        case "docs":
                            if (Uri.TryCreate(BaseUri, E.InnerText, out Uri Documentation))
                                this.Documentation = Documentation;
                            else
                                Warnings.Add(new RssWarning(E, "Invalid URI: " + E.InnerText));
                            break;
 
                        case "ttl":
                            if (int.TryParse(E.InnerText, out int Ttl))
                                this.TimeToLive = TimeSpan.FromMinutes(Ttl);
                            else
                                Warnings.Add(new RssWarning(E, "Unable to parse TTL: " + E.InnerText));
                            break;
 
                        case "image":
                            if (!(this.Image is null))
                                Warnings.Add(new RssWarning(E, "Image already defined for channel."));
                            else
                            {
                                this.Image = new RssImage(E, BaseUri);
                                Warnings.AddRange(this.Image.Warnings);
                            }
                            break;
 
                        case "item":
                            RssItem Item = new RssItem(E, BaseUri);
                            Warnings.AddRange(Item.Warnings);
                            Items.Add(Item);
                            break;
 
                        case "cloud":
                            if (!(this.Cloud is null))
                                Warnings.Add(new RssWarning(E, "Cloud service already defined for channel."));
                            else
                                this.Cloud = new RssCloud(E, BaseUri);
                            break;
 
                        case "rating":      // TODO
                        case "textInput":   // TODO
                        case "skipHours":   // TODO
                        case "skipDays":    // TODO
                        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.Categories = Categories.ToArray();
            this.Items = Items.ToArray();
            this.Warnings = Warnings.ToArray();
            this.Extensions = Extensions.ToArray();
        }
 
        public RssWarning[] Warnings { get; } = null;
 
        public string Title { get; } = null;
 
        public Uri Link { get; } = null;
 
        public string Description { get; } = null;
 
        public string Language { get; } = null;
 
        public string Copyright { get; } = null;
 
        public string ManagingEditor { get; } = null;
 
        public string WebMaster { get; } = null;
 
        public DateTimeOffset? PublicationDate { get; } = null;
 
        public DateTimeOffset? LastBuildDate { get; } = null;
 
        public RssCategory[] Categories { get; } = null;
 
        public string Generator { get; } = null;
 
        public Uri Documentation { get; } = null;
 
        public RssCloud Cloud { get; } = null;
 
        public TimeSpan TimeToLive { get; } = TimeSpan.FromMinutes(60);
 
        public RssImage Image { get; } = null;
 
        public RssItem[] Items { get; } = null;
 
        public IRssExtension[] Extensions { get; } = null;
    }
}