IsContent.cs

using System;
using System.IO;
using System.Threading.Tasks;
using System.Xml;
using Waher.Content.Xml;
using Waher.Content.Xml.Attributes;
using Waher.Events;
using Waher.Networking.HTTP.Interfaces;
 
namespace Waher.Security.WAF.Model.Comparisons
{
    public class IsContent : WafComparison
    {
        private readonly StringAttribute manifestFile;
 
        public IsContent()
            : base()
        {
        }
 
        public IsContent(XmlElement Xml, WafAction Parent, WebApplicationFirewall Document)
            : base(Xml, Parent, Document)
        {
            this.manifestFile = new StringAttribute(Xml, "manifestFile");
        }
 
        public override string LocalName => nameof(IsContent);
 
        public override WafAction Create(XmlElement Xml, WafAction Parent, WebApplicationFirewall Document) => new IsContent(Xml, Parent, Document);
 
        public override async Task<WafResult?> Review(ProcessingState State)
        {
            if (!State.Request.Server.TryGetFileName(State.Request.Header.ResourcePart,
                false, out string ResourceFileName))
            {
                return null;
            }
 
            string ManifestFileName = await this.manifestFile.EvaluateAsync(State.Variables, string.Empty);
            string Key = ResourceFileName + "|C|" + ManifestFileName;
 
            if (!State.TryGetCachedObject(Key, out bool IsMatch))
            {
                if (!File.Exists(ManifestFileName))
                    ManifestFileName = Path.Combine(State.Firewall.AppDataFolder, ManifestFileName);
 
                if (ResourceFileName.StartsWith(State.Firewall.AppDataFolder, StringComparison.OrdinalIgnoreCase))
                    ResourceFileName = ResourceFileName[State.Firewall.AppDataFolder.Length..];
 
                if (ResourceFileName.StartsWith('/'))
                    ResourceFileName = ResourceFileName[1..];
 
                IsMatch = CheckMatch(ManifestFileName, ResourceFileName);
 
                State.AddToCache(Key, IsMatch, fiveMinutes);
            }
 
            return IsMatch ? await this.ReviewChildren(State) : null;
        }
 
        private static bool CheckMatch(string ManifestFileName, string ContentFileName)
        {
            try
            {
                if (!File.Exists(ManifestFileName))
                    return false;
 
                XmlDocument Doc = XML.LoadFromFile(ManifestFileName);
 
                if (Doc.DocumentElement is null ||
                    Doc.DocumentElement.LocalName != "Module" ||
                    Doc.DocumentElement.NamespaceURI != "http://waher.se/Schema/ModuleManifest.xsd")
                {
                    return false;
                }
 
                XmlElement Loop = Doc.DocumentElement;
                string[] Parts = ContentFileName.Split(pathSeparators);
                int i, c = Parts.Length;
 
                for (i = string.IsNullOrEmpty(Parts[0]) ? 1 : 0; i < c; i++)
                {
                    XmlElement Found = null;
 
                    foreach (XmlNode N in Loop.ChildNodes)
                    {
                        if (!(N is XmlElement E))
                            continue;
 
                        if (i == c - 1)
                        {
                            if (E.LocalName == "Content" &&
                                E.HasAttribute("fileName") &&
                                E.GetAttribute("fileName").Equals(Parts[i], StringComparison.CurrentCultureIgnoreCase))
                            {
                                Found = E;
                                break;
                            }
                        }
                        else
                        {
                            if (E.LocalName == "Folder" &&
                                E.HasAttribute("name") &&
                                E.GetAttribute("name").Equals(Parts[i], StringComparison.CurrentCultureIgnoreCase))
                            {
                                Found = E;
                                break;
                            }
                        }
                    }
 
                    if (Found is null)
                        return false;
                    else
                        Loop = Found;
                }
 
                return true;
            }
            catch (Exception ex)
            {
                Log.Exception(ex, ManifestFileName);
                return false;
            }
        }
 
        private static readonly char[] pathSeparators = new char[] { '/', '\\' };
    }
}