WafAction.cs

using System;
using System.Collections.Generic;
using System.Reflection;
using System.Threading.Tasks;
using System.Xml;
using Waher.Content.Xml;
using Waher.Events;
using Waher.Networking.HTTP.Interfaces;
using Waher.Runtime.Inventory;
 
namespace Waher.Security.WAF.Model
{
    public abstract class WafAction : IWafAction
    {
        private static readonly Dictionary<string, IWafAction> actionTypes = GetActionTypes();
 
        private readonly string id;
        private readonly WafAction parent;
        private readonly WebApplicationFirewall document;
 
        public WafAction()
        {
        }
 
        public WafAction(XmlElement Xml, WafAction Parent, WebApplicationFirewall Document)
        {
            this.id = XML.Attribute(Xml, "id");
            this.parent = Parent;
            this.document = Document;
 
            if (!string.IsNullOrEmpty(this.id))
                Document.RegisterAction(this);
        }
 
        public abstract string LocalName { get; }
 
        public string Id => this.id;
 
        public WebApplicationFirewall Document => this.document;
 
        public abstract WafAction Create(XmlElement Xml, WafAction Parent, WebApplicationFirewall Document);
 
        private static Dictionary<string, IWafAction> GetActionTypes()
        {
            Dictionary<string, IWafAction> Result = new Dictionary<string, IWafAction>();
 
            foreach (Type ActionType in Types.GetTypesImplementingInterface(typeof(IWafAction)))
            {
                ConstructorInfo CI = Types.GetDefaultConstructor(ActionType);
                if (CI is null)
                    continue;
 
                IWafAction Action = (IWafAction)CI.Invoke(Array.Empty<object>());
 
                if (Result.ContainsKey(Action.LocalName))
                    Log.Error("Duplicate WAF action definition: " + Action.LocalName);
                else
                    Result[Action.LocalName] = Action;
            }
 
            return Result;
        }
 
        public static WafAction Parse(XmlElement Xml, WafAction Parent, WebApplicationFirewall Document)
        {
            if (Xml is null)
                throw new ArgumentNullException(nameof(Xml));
 
            if (Xml.NamespaceURI != WebApplicationFirewall.Namespace)
                throw new Exception("Invalid WAF namespace.");
 
            if (!actionTypes.TryGetValue(Xml.LocalName, out IWafAction Action))
                throw new Exception("Unrecognized WAF action: " + Xml.LocalName);
 
            return Action.Create(Xml, Parent, Document);
        }
 
        public virtual void Prepare()
        {
            // Do nothing by default.
        }
 
        public abstract Task<WafResult?> Review(ProcessingState State);
 
        protected static readonly TimeSpan fiveMinutes = TimeSpan.FromMinutes(5);
    }
}