PublicNodes.cs

using System;
using System.Collections.Generic;
using System.Text;
using System.Threading.Tasks;
using System.Web;
using Waher.Content;
using Waher.Content.Xml;
using Waher.Content.Xml.Text;
using Waher.Networking.HTTP;
using Waher.Persistence;
using Waher.Persistence.Filters;
using Waher.Service.IoTBroker.PubSub;
 
namespace Waher.Service.IoTBroker.WebServices
{
    public class PublicNodes : HttpSynchronousResource, IHttpGetMethod
    {
        public PublicNodes()
            : base("/PubSub")
        {
        }
 
        public override bool HandlesSubPaths => true;
        public override bool UserSessions => true;
        public bool AllowsGET => true;
 
        public async Task GET(HttpRequest Request, HttpResponse Response)
        {
            if (string.IsNullOrEmpty(Request.SubPath))
                throw new BadRequestException("Sub-path must be specified for this request.");
 
            int i = Request.SubPath.IndexOf('/', 1);
            string NodeName = HttpUtility.UrlDecode(i < 0 ? Request.SubPath[1..] : Request.SubPath[1..i]);
            CaseInsensitiveString ItemId = i < 0 ? string.Empty : HttpUtility.UrlDecode(Request.SubPath[i..]);
 
            PubSubNode Node = await XmppServerModule.GetPubSubNodeAsync(NodeName)
                ?? throw new NotFoundException("PubSub node `" + NodeName + "` not found.");
 
            if (Node.AccessModel != NodeAccessModel.open)
                throw new ForbiddenException("Node is not configured for open public access.");
 
            string Xml;
 
            if (CaseInsensitiveString.IsNullOrEmpty(ItemId))
            {
                StringBuilder sb = new StringBuilder();
                string Url = Request.Header.GetURL();
                bool First;
 
                sb.AppendLine("<?xml version=\"1.0\" encoding=\"UTF-8\" ?>");
                sb.AppendLine("<rss version=\"2.0\">");
                sb.AppendLine("<channel>");
                sb.Append("<title>");
                sb.Append(XML.Encode(string.IsNullOrEmpty(Node.Title) ? NodeName : Node.Title));
                sb.AppendLine("</title>");
                sb.Append("<link>");
                sb.Append(XML.Encode(Url));
                sb.AppendLine("</link>");
                sb.Append("<description>");
                
                if (!(Node.Description is null))
                {
                    First = true;
                    foreach (string s in Node.Description)
                    {
                        if (First)
                            First = false;
                        else
                            sb.AppendLine();
 
                        sb.Append(s);
                    }
                }
 
                sb.AppendLine("</description>");
 
                if (!string.IsNullOrEmpty(Node.Language))
                {
                    sb.Append("<language>");
                    sb.Append(XML.Encode(Node.Language));
                    sb.AppendLine("</language>");
                }
 
                IEnumerable<PubSubItem> Items = await Database.Find<PubSubItem>(0, 20, 
                    new FilterAnd(
                    new FilterFieldEqualTo("Service", CaseInsensitiveString.Empty),
                    new FilterFieldEqualTo("Node", NodeName)), 
                    "-Service", "-Node", "-Created");
 
                First = true;
 
                foreach (PubSubItem Item in Items)
                {
                    if (First)
                    {
                        First = false;
                        sb.Append("<pubDate>");
                        sb.Append(CommonTypes.EncodeRfc822(Item.Updated == DateTime.MinValue ? Item.Created : Item.Updated));
                        sb.AppendLine("</pubDate>");
                    }
 
                    sb.AppendLine("<item>");
                    sb.Append("<title>");
                    sb.Append(XML.Encode(Item.ItemId));
                    sb.AppendLine("</title>");
                    sb.Append("<author>");
                    sb.Append(Item.Publisher.Value);
                    sb.AppendLine("</author>");
                    sb.Append("<pubDate>");
                    sb.Append(CommonTypes.EncodeRfc822(Item.Updated == DateTime.MinValue ? Item.Created : Item.Updated));
                    sb.AppendLine("</pubDate>");
                    sb.AppendLine("<description>Published item</description>");
                    sb.Append("<link>");
                    sb.Append(XML.Encode(Url));
                    if (!Item.ItemId.StartsWith("/"))
                        sb.Append('/');
                    sb.Append(XML.Encode(Item.ItemId));
                    sb.AppendLine("</link>");
                    sb.Append("<guid isPermaLink=\"false\">");
                    sb.Append(XML.Encode(Item.ObjectId));
                    sb.AppendLine("</guid>");
                    sb.AppendLine("</item>");
                }
 
                sb.AppendLine("</channel>");
                sb.AppendLine("</rss>");
 
                Xml = sb.ToString();
            }
            else
            {
                PubSubItem Item = await XmppServerModule.PubSub.LoadItem(CaseInsensitiveString.Empty, NodeName, ItemId);
 
                if (Item is null && ItemId.StartsWith("/"))
                    Item = await XmppServerModule.PubSub.LoadItem(CaseInsensitiveString.Empty, NodeName, ItemId.Substring(1));
                    
                if (Item is null)
                    throw new NotFoundException("PubSub item `" + ItemId + "` on node `" + NodeName + "` not found.");
 
                Xml = Item.Payload;
            }
 
            Response.ContentType = XmlCodec.DefaultContentType;
            await Response.Write(Xml);
        }
    }
}