maintenance expiration vs build date checking code

server/AyaNova/util/FileUtil.cs

@@ -8,6 +8,7 @@ using Microsoft.Extensions.Logging;
 using Microsoft.EntityFrameworkCore;
 using AyaNova.Models;
 using AyaNova.Biz;
+using System.Reflection;
 
 namespace AyaNova.Util
 {
@@ -481,7 +482,7 @@ namespace AyaNova.Util
                 AttachToAType = attachToObject.AType,
                 LastModified = lastModified,
                 Size = FileSize,
-                AttachedByUserId=attachedByUserId
+                AttachedByUserId = attachedByUserId
 
             };
 
@@ -828,7 +829,7 @@ namespace AyaNova.Util
             {
                 return string.Empty;
             }
-           
+
             //Linux ~ home folder special handling here
             if (path.Contains('~'))
             {
@@ -841,6 +842,34 @@ namespace AyaNova.Util
         }
         #endregion general utilities
 
+
+        #region licensing related utility to qualify upgradability
+        //https://www.meziantou.net/getting-the-date-of-build-of-a-dotnet-assembly-at-runtime.htm
+        public static DateTime GetLinkerTimestampUtc(Assembly assembly)
+        {
+            var location = assembly.Location;
+            return GetLinkerTimestampUtc(location);
+        }
+
+        public static DateTime GetLinkerTimestampUtc(string filePath)
+        {
+            const int peHeaderOffset = 60;
+            const int linkerTimestampOffset = 8;
+            var bytes = new byte[2048];
+
+            using (var file = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
+            {
+                file.Read(bytes, 0, bytes.Length);
+            }
+
+            var headerPos = BitConverter.ToInt32(bytes, peHeaderOffset);
+            var secondsSince1970 = BitConverter.ToInt32(bytes, headerPos + linkerTimestampOffset);
+            var dt = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+            return dt.AddSeconds(secondsSince1970);
+        }
+        #endregion
+
+
     }//eoc
 
 }//eons

server/AyaNova/util/ImportUtil.cs

@@ -1,8 +1,6 @@
 using System;
 using System.Reflection;
-using System.Linq;
 using System.Collections.Generic;
-using Newtonsoft.Json.Linq;
 
 namespace AyaNova.Util
 {
@@ -63,7 +61,8 @@ namespace AyaNova.Util
         }
 
 
-       
+
+
 
     }//eoc
 

server/AyaNova/util/License.cs

@@ -799,7 +799,7 @@ namespace AyaNova.Core
                     throw new ApplicationException("E1020 - Can't install a trial key into a non empty AyaNova database.  Erase the database first.");
                 }
 
-                //TODO: TECHCOUNT - new license causes exceeding count?  
+                //TECHCOUNT - new license causes exceeding count?  
                 long NewTechCount = ParsedNewKey.GetLicenseFeature(SERVICE_TECHS_FEATURE_NAME).Count;
                 if (await AyaNova.Biz.UserBiz.ActiveCountAsync() > NewTechCount)
                 {
@@ -925,6 +925,15 @@ EQIDAQAB
 
 
                 #endregion get values
+
+                //Check if attempting to use a build of AyaNova that is newer than maintenance subscription expiry 
+                if (MExBB(Util.FileUtil.GetLinkerTimestampUtc(System.Reflection.Assembly.GetExecutingAssembly()), key))
+                {
+                    Console.WriteLine("E1020 - Not licensed for this version of AyaNova. Fix: downgrade back to previous version in use or contact technical support for options.");                    
+                    
+                    //NOTE: VERSION-TOO-NEW  bit below is checked for in startup.cs DO NOT remove this without fixing the side effects
+                    throw new ApplicationException("E1020 VERSION-TOO-NEW - Not licensed for this version of AyaNova. Fix: downgrade back to previous version in use or contact technical support for options.");
+                }
                 //All is well return key
                 return key;
 
@@ -942,6 +951,12 @@ EQIDAQAB
 
 
 
+        #region Validate Build date against maintenance date in license
+        //MaintenanceExpirationBeforeBuild?
+        internal static bool MExBB(DateTime dtB, AyaNovaLicenseKey k) => k.MaintenanceExpiration < dtB;
+        #endregion
+
+
 
     }//eoc