Publish.cs

using System;
using System.Collections.Generic;
using System.Text;
using System.Xml;
using System.Threading.Tasks;
using TAG.Simulator.ObjectModel;
using TAG.Simulator.ObjectModel.Activities;
using TAG.Simulator.ObjectModel.Values;
using TAG.Simulator.MQTT.Actors;
using Waher.Content.Xml;
using Waher.Script;
using Waher.Networking.MQTT;
using System.IO;
using Waher.Content;
 
namespace TAG.Simulator.MQTT.Activities
{
    public class Publish : ActivityNode, IValueRecipient
    {
        private IValue value;
        private MqttQualityOfService qos;
        private StringAttribute actor;
        private StringAttribute topic;
        private bool retain;
 
        public Publish(ISimulationNode Parent, Model Model)
            : base(Parent, Model)
        {
        }
 
        public override string LocalName => nameof(Publish);
 
        public override string SchemaResource => MqttActorTcp.MqttSchema;
 
        public override string Namespace => MqttActorTcp.MqttNamespace;
 
        public override ISimulationNode Create(ISimulationNode Parent, Model Model)
        {
            return new Publish(Parent, Model);
        }
 
        public override Task FromXml(XmlElement Definition)
        {
            this.actor = new StringAttribute(XML.Attribute(Definition, "actor"));
            this.topic = new StringAttribute(XML.Attribute(Definition, "topic"));
            this.qos = (MqttQualityOfService)XML.Attribute(Definition, "qos", MqttQualityOfService.AtMostOnce);
            this.retain = XML.Attribute(Definition, "retain", false);
 
            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 Topic = await this.topic.GetValueAsync(Variables);
            object Content = this.value is null ? string.Empty : await this.value.EvaluateAsync(Variables) ?? string.Empty;
 
            if (!(Content is byte[] Bin))
            {
                KeyValuePair<byte[], string> P = await InternetContent.EncodeAsync(Content, Encoding.UTF8);
                Bin = P.Key;
            }
 
            if (!(await this.GetActorObjectAsync(this.actor, Variables) is MqttActivityObject MqttActor))
                throw new Exception("Actor not an MQTT actor.");
 
            await MqttActor.Client.PUBLISH(Topic, this.qos, this.retain, Bin);
 
            return null;
        }
 
        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(".Publish");
            Output.Write("(");
 
            Indentation++;
 
            this.AppendArgument(Output, Indentation, "Topic", this.topic.Value, true, QuoteChar);
            this.AppendArgument(Output, Indentation, "QoS", this.qos.ToString(), false, QuoteChar);
 
            if (!this.retain)
                this.AppendArgument(Output, Indentation, "Retain", "true", false, QuoteChar);
 
            if (!(this.value is null))
            {
                if (this.value is Xml Xml && !string.IsNullOrEmpty(Xml.RootName))
                    this.AppendArgument(Output, Indentation, "Content", Xml.RootName, false, QuoteChar);
                else
                    this.AppendArgument(Output, Indentation, "Content", this.value, QuoteChar);
            }
 
            Output.WriteLine(");");
        }
 
        private void AppendArgument(StreamWriter Output, int Indentation, string Name, string Value, bool Quotes, char QuoteChar)
        {
            this.AppendArgument(Output, Indentation, Name);
 
            if (Quotes)
                Eval.ExportPlantUml("\"" + Value.Replace("\"", "\\\"") + "\"", Output, Indentation, QuoteChar, false);
            else
                Eval.ExportPlantUml(Value, Output, Indentation, QuoteChar, false);
        }
 
        private void AppendArgument(StreamWriter Output, int Indentation, string Name, IValue Value, char QuoteChar)
        {
            this.AppendArgument(Output, Indentation, Name);
            Value.ExportPlantUml(Output, Indentation, QuoteChar);
        }
 
        private void AppendArgument(StreamWriter Output, int Indentation, string Name)
        {
            Output.WriteLine();
            Indent(Output, Indentation);
 
            Output.Write(Name);
            Output.Write(": ");
        }
 
    }
}