Request.cs

using System;
using System.Collections.Generic;
using System.Xml;
using System.Threading.Tasks;
using TAG.Simulator.ObjectModel;
using TAG.Simulator.ObjectModel.Activities;
using TAG.Simulator.ObjectModel.Values;
using TAG.Simulator.XMPP.Actors;
using Waher.Content.Xml;
using Waher.Script;
using Waher.Networking.XMPP;
using System.IO;
 
namespace TAG.Simulator.XMPP.Activities
{
    public enum RequestType
    {
        Get,
 
        Set
    }
 
    public class Request : ActivityNode, IValueRecipient
    {
        private IValue value;
        private RequestType type;
        private StringAttribute actor;
        private StringAttribute to;
        private string responseVariable;
 
        public Request(ISimulationNode Parent, Model Model)
            : base(Parent, Model)
        {
        }
 
        public override string LocalName => nameof(Request);
 
        public override string SchemaResource => XmppActor.XmppSchema;
 
        public override string Namespace => XmppActor.XmppNamespace;
 
        public override ISimulationNode Create(ISimulationNode Parent, Model Model)
        {
            return new Request(Parent, Model);
        }
 
        public override Task FromXml(XmlElement Definition)
        {
            this.actor = new StringAttribute(XML.Attribute(Definition, "actor"));
            this.to = new StringAttribute(XML.Attribute(Definition, "to"));
            this.type = (RequestType)XML.Attribute(Definition, "type", RequestType.Get);
            this.responseVariable = XML.Attribute(Definition, "responseVariable");
 
            return base.FromXml(Definition);
        }
 
        public void Register(IValue Value)
        {
            if (this.value is null)
                this.value = Value;
            else
                throw new Exception("Value already registered.");
        }
 
        public override async Task<LinkedListNode<IActivityNode>> Execute(Variables Variables)
        {
            string To = await this.to.GetValueAsync(Variables);
            object Content = this.value is null ? string.Empty : await this.value.EvaluateAsync(Variables) ?? string.Empty;
            string Xml;
 
            if (!(await this.GetActorObjectAsync(this.actor, Variables) is XmppActivityObject XmppActor))
                throw new Exception("Actor not an XMPP client.");
 
            if (Content is XmlDocument Doc)
                Xml = Doc.OuterXml;
            else if (Content is XmlElement E)
                Xml = E.OuterXml;
            else
                throw new Exception("Requests must be XML.");
 
            TaskCompletionSource<LinkedListNode<IActivityNode>> T = new TaskCompletionSource<LinkedListNode<IActivityNode>>();
 
            await XmppActor.Client.SendIq(string.Empty, To, Xml, this.type.ToString().ToLower(), (sender, e) =>
            {
                if (e.Ok)
                {
                    Variables[this.responseVariable] = e.FirstElement;
                    T.TrySetResult(null);
                }
                else
                    T.TrySetException(new XmppException(string.IsNullOrEmpty(e.ErrorText) ? "Error response returned." : e.ErrorText));
 
                return Task.CompletedTask;
            }, null, XmppActor.Client.DefaultRetryTimeout, XmppActor.Client.DefaultNrRetries, XmppActor.Client.DefaultDropOff, XmppActor.Client.DefaultMaxRetryTimeout);
 
            return await T.Task;
        }
 
        public override void ExportPlantUml(StreamWriter Output, int Indentation, char QuoteChar)
        {
            base.ExportPlantUml(Output, Indentation, QuoteChar);
 
            Indent(Output, Indentation);
            Output.Write(':');
            Output.Write(this.actor.Value);
            Output.Write(".Request");
            Output.Write("(");
 
            Indentation++;
 
            SendMessage.AppendArgument(Output, Indentation, "To", this.to.Value, true, QuoteChar);
            SendMessage.AppendArgument(Output, Indentation, "Type", this.type.ToString(), false, QuoteChar);
 
            if (!(this.value is null))
            {
                if (this.value is Xml Xml && !string.IsNullOrEmpty(Xml.RootName))
                    SendMessage.AppendArgument(Output, Indentation, "Content", Xml.RootName, false, QuoteChar);
                else
                    SendMessage.AppendArgument(Output, Indentation, "Content", this.value, QuoteChar);
            }
 
            Output.WriteLine(");");
        }
 
    }
}