Maintain ttl on update (#340)

Author: zulander1

src/Redis.OM/Scripts.cs

@@ -81,8 +81,12 @@ local second_op
         /// Unlinks a JSON object and sets the key again with a fresh new JSON object.
         /// </summary>
         internal const string UnlinkAndSendJson = @"
+local expiry = tonumber(redis.call('PTTL', KEYS[1]))
 redis.call('UNLINK', KEYS[1])
 redis.call('JSON.SET', KEYS[1], '.', ARGV[1])
+    if expiry > 0 then
+        redis.call('PEXPIRE', KEYS[1], expiry)
+    end
 return 0
 ";
 
@@ -100,8 +104,8 @@ local second_op
     redis.call('HSET', KEYS[1], unpack(hashArgs))
     if expiry > 0 then
         redis.call('PEXPIRE', KEYS[1], expiry)
-    end 
-    return 1    
+    end
+    return 1
 end
 return 0
 ";
@@ -151,7 +155,7 @@ local second_op
         /// <summary>
         /// The scripts.
         /// </summary>
-        internal static readonly Dictionary<string, string> ScriptCollection = new ()
+        internal static readonly Dictionary<string, string> ScriptCollection = new()
         {
             { nameof(JsonDiffResolution), JsonDiffResolution },
             { nameof(HashDiffResolution), HashDiffResolution },
@@ -166,6 +170,6 @@ local second_op
         /// <summary>
         /// Gets or sets collection of SHAs.
         /// </summary>
-        internal static ConcurrentDictionary<string, string> ShaCollection { get; set; } = new ();
+        internal static ConcurrentDictionary<string, string> ShaCollection { get; set; } = new();
     }
-}
+}