Support OBJECT REFCOUNT

docs/ReleaseNotes.md

@@ -15,6 +15,7 @@
 - Adds: Support for `SINTERCARD` with `.SetIntersectionLength()`/`.SetIntersectionLengthAsync()` ([#2078 by Avital-Fine](https://github.com/StackExchange/StackExchange.Redis/pull/2078))
 - Adds: Support for `LPOS` with `.ListPosition()`/`.ListPositionAsync()` and `.ListPositions()`/`.ListPositionsAsync()` ([#2080 by slorello89](https://github.com/StackExchange/StackExchange.Redis/pull/2080))
 - Fix: For streams, properly hash `XACK`, `XCLAIM`, and `XPENDING` in cluster scenarios to eliminate `MOVED` retries ([#2085 by nielsderdaele](https://github.com/StackExchange/StackExchange.Redis/pull/2085))
+- Adds: Support for `OBJECT REFCOUNT` with `.KeyRefCount()`/`.KeyRefCountAsync()` ([#2087 by Avital-Fine](https://github.com/StackExchange/StackExchange.Redis/pull/2087))
 
 ## 2.5.61
 

src/StackExchange.Redis/Interfaces/IDatabase.cs

@@ -620,6 +620,15 @@ public interface IDatabase : IRedis, IDatabaseAsync
         /// <remarks>https://redis.io/commands/randomkey</remarks>
         RedisKey KeyRandom(CommandFlags flags = CommandFlags.None);
 
+        /// <summary>
+        /// Returns the reference count of the object stored at <paramref name="key"/>.
+        /// </summary>
+        /// <param name="key">The key to get a reference count for.</param>
+        /// <param name="flags">The flags to use for this operation.</param>
+        /// <returns>The number of references (0 if the key does not exist).</returns>
+        /// <remarks>https://redis.io/commands/object-refcount</remarks>
+        long? KeyRefCount(RedisKey key, CommandFlags flags = CommandFlags.None);
+
         /// <summary>
         /// Renames <paramref name="key"/> to <paramref name="newKey"/>.
         /// It returns an error when the source and destination names are the same, or when key does not exist.

src/StackExchange.Redis/Interfaces/IDatabaseAsync.cs

@@ -596,6 +596,15 @@ public interface IDatabaseAsync : IRedisAsync
         /// <remarks>https://redis.io/commands/randomkey</remarks>
         Task<RedisKey> KeyRandomAsync(CommandFlags flags = CommandFlags.None);
 
+        /// <summary>
+        /// Returns the reference count of the object stored at <paramref name="key"/>.
+        /// </summary>
+        /// <param name="key">The key to get a reference count for.</param>
+        /// <param name="flags">The flags to use for this operation.</param>
+        /// <returns>The number of references (0 if the key does not exist).</returns>
+        /// <remarks>https://redis.io/commands/object-refcount</remarks>
+        Task<long?> KeyRefCountAsync(RedisKey key, CommandFlags flags = CommandFlags.None);
+
         /// <summary>
         /// Renames <paramref name="key"/> to <paramref name="newKey"/>.
         /// It returns an error when the source and destination names are the same, or when key does not exist.

src/StackExchange.Redis/KeyspaceIsolation/DatabaseWrapper.cs

@@ -164,6 +164,9 @@ public bool KeyPersist(RedisKey key, CommandFlags flags = CommandFlags.None) =>
         public RedisKey KeyRandom(CommandFlags flags = CommandFlags.None) =>
             throw new NotSupportedException("RANDOMKEY is not supported when a key-prefix is specified");
 
+        public long? KeyRefCount(RedisKey key, CommandFlags flags = CommandFlags.None) =>
+            Inner.KeyRefCount(ToInner(key), flags);
+
         public bool KeyRename(RedisKey key, RedisKey newKey, When when = When.Always, CommandFlags flags = CommandFlags.None) =>
             Inner.KeyRename(ToInner(key), ToInner(newKey), when, flags);
 

src/StackExchange.Redis/KeyspaceIsolation/WrapperBase.cs

@@ -174,6 +174,9 @@ public Task<bool> KeyPersistAsync(RedisKey key, CommandFlags flags = CommandFlag
         public Task<RedisKey> KeyRandomAsync(CommandFlags flags = CommandFlags.None) =>
             throw new NotSupportedException("RANDOMKEY is not supported when a key-prefix is specified");
 
+        public Task<long?> KeyRefCountAsync(RedisKey key, CommandFlags flags = CommandFlags.None) =>
+            Inner.KeyRefCountAsync(ToInner(key), flags);
+
         public Task<bool> KeyRenameAsync(RedisKey key, RedisKey newKey, When when = When.Always, CommandFlags flags = CommandFlags.None) =>
             Inner.KeyRenameAsync(ToInner(key), ToInner(newKey), when, flags);
 

src/StackExchange.Redis/PublicAPI.Shipped.txt

@@ -531,6 +531,7 @@ StackExchange.Redis.IDatabase.KeyMigrate(StackExchange.Redis.RedisKey key, Syste
 StackExchange.Redis.IDatabase.KeyMove(StackExchange.Redis.RedisKey key, int database, StackExchange.Redis.CommandFlags flags = StackExchange.Redis.CommandFlags.None) -> bool
 StackExchange.Redis.IDatabase.KeyPersist(StackExchange.Redis.RedisKey key, StackExchange.Redis.CommandFlags flags = StackExchange.Redis.CommandFlags.None) -> bool
 StackExchange.Redis.IDatabase.KeyRandom(StackExchange.Redis.CommandFlags flags = StackExchange.Redis.CommandFlags.None) -> StackExchange.Redis.RedisKey
+StackExchange.Redis.IDatabase.KeyRefCount(StackExchange.Redis.RedisKey key, StackExchange.Redis.CommandFlags flags = StackExchange.Redis.CommandFlags.None) -> long?
 StackExchange.Redis.IDatabase.KeyRename(StackExchange.Redis.RedisKey key, StackExchange.Redis.RedisKey newKey, StackExchange.Redis.When when = StackExchange.Redis.When.Always, StackExchange.Redis.CommandFlags flags = StackExchange.Redis.CommandFlags.None) -> bool
 StackExchange.Redis.IDatabase.KeyRestore(StackExchange.Redis.RedisKey key, byte[]! value, System.TimeSpan? expiry = null, StackExchange.Redis.CommandFlags flags = StackExchange.Redis.CommandFlags.None) -> void
 StackExchange.Redis.IDatabase.KeyTimeToLive(StackExchange.Redis.RedisKey key, StackExchange.Redis.CommandFlags flags = StackExchange.Redis.CommandFlags.None) -> System.TimeSpan?
@@ -731,6 +732,7 @@ StackExchange.Redis.IDatabaseAsync.KeyMigrateAsync(StackExchange.Redis.RedisKey
 StackExchange.Redis.IDatabaseAsync.KeyMoveAsync(StackExchange.Redis.RedisKey key, int database, StackExchange.Redis.CommandFlags flags = StackExchange.Redis.CommandFlags.None) -> System.Threading.Tasks.Task<bool>!
 StackExchange.Redis.IDatabaseAsync.KeyPersistAsync(StackExchange.Redis.RedisKey key, StackExchange.Redis.CommandFlags flags = StackExchange.Redis.CommandFlags.None) -> System.Threading.Tasks.Task<bool>!
 StackExchange.Redis.IDatabaseAsync.KeyRandomAsync(StackExchange.Redis.CommandFlags flags = StackExchange.Redis.CommandFlags.None) -> System.Threading.Tasks.Task<StackExchange.Redis.RedisKey>!
+StackExchange.Redis.IDatabaseAsync.KeyRefCountAsync(StackExchange.Redis.RedisKey key, StackExchange.Redis.CommandFlags flags = StackExchange.Redis.CommandFlags.None) -> System.Threading.Tasks.Task<long?>!
 StackExchange.Redis.IDatabaseAsync.KeyRenameAsync(StackExchange.Redis.RedisKey key, StackExchange.Redis.RedisKey newKey, StackExchange.Redis.When when = StackExchange.Redis.When.Always, StackExchange.Redis.CommandFlags flags = StackExchange.Redis.CommandFlags.None) -> System.Threading.Tasks.Task<bool>!
 StackExchange.Redis.IDatabaseAsync.KeyRestoreAsync(StackExchange.Redis.RedisKey key, byte[]! value, System.TimeSpan? expiry = null, StackExchange.Redis.CommandFlags flags = StackExchange.Redis.CommandFlags.None) -> System.Threading.Tasks.Task!
 StackExchange.Redis.IDatabaseAsync.KeyTimeToLiveAsync(StackExchange.Redis.RedisKey key, StackExchange.Redis.CommandFlags flags = StackExchange.Redis.CommandFlags.None) -> System.Threading.Tasks.Task<System.TimeSpan?>!

src/StackExchange.Redis/RedisDatabase.cs

@@ -827,6 +827,18 @@ public Task<RedisKey> KeyRandomAsync(CommandFlags flags = CommandFlags.None)
             return ExecuteAsync(msg, ResultProcessor.RedisKey);
         }
 
+        public long? KeyRefCount(RedisKey key, CommandFlags flags = CommandFlags.None)
+        {
+            var msg = Message.Create(Database, flags, RedisCommand.OBJECT, RedisLiterals.REFCOUNT, key);
+            return ExecuteSync(msg, ResultProcessor.NullableInt64);
+        }
+
+        public Task<long?> KeyRefCountAsync(RedisKey key, CommandFlags flags = CommandFlags.None)
+        {
+            var msg = Message.Create(Database, flags, RedisCommand.OBJECT, RedisLiterals.REFCOUNT, key);
+            return ExecuteAsync(msg, ResultProcessor.NullableInt64);
+        }
+
         public bool KeyRename(RedisKey key, RedisKey newKey, When when = When.Always, CommandFlags flags = CommandFlags.None)
         {
             WhenAlwaysOrNotExists(when);

src/StackExchange.Redis/RedisLiterals.cs

@@ -92,12 +92,13 @@ public static readonly RedisValue
             PX = "PX",
             PXAT = "PXAT",
             RANK = "RANK",
-            RIGHT = "RIGHT",
+            REFCOUNT = "REFCOUNT",
             REPLACE = "REPLACE",
             RESET = "RESET",
             RESETSTAT = "RESETSTAT",
             REV = "REV",
             REWRITE = "REWRITE",
+            RIGHT = "RIGHT",
             SAVE = "SAVE",
             SEGFAULT = "SEGFAULT",
             SET = "SET",

tests/StackExchange.Redis.Tests/DatabaseWrapperTests.cs

@@ -317,6 +317,13 @@ public void KeyRandom()
             Assert.Throws<NotSupportedException>(() => wrapper.KeyRandom());
         }
 
+        [Fact]
+        public void KeyRefCount()
+        {
+            wrapper.KeyRefCount("key", CommandFlags.None);
+            mock.Verify(_ => _.KeyRefCount("prefix:key", CommandFlags.None));
+        }
+
         [Fact]
         public void KeyRename()
         {

tests/StackExchange.Redis.Tests/Keys.cs

@@ -264,5 +264,22 @@ public async Task TouchIdleTimeAsync()
                 Assert.True(idleTime1 < idleTime);
             }
         }
+
+        [Fact]
+        public async Task KeyRefCount()
+        {
+            using var muxer = Create();
+            var key = Me();
+            var db = muxer.GetDatabase();
+            db.KeyDelete(key, CommandFlags.FireAndForget);
+            db.StringSet(key, "new value", flags: CommandFlags.FireAndForget);
+
+            Assert.Equal(1, db.KeyRefCount(key));
+            Assert.Equal(1, await db.KeyRefCountAsync(key));
+
+            var keyNotExists = key + "no-exist";
+            Assert.Null(db.KeyRefCount(keyNotExists));
+            Assert.Null(await db.KeyRefCountAsync(keyNotExists));
+        }
     }
 }

tests/StackExchange.Redis.Tests/WrapperBaseTests.cs

@@ -277,6 +277,13 @@ public Task KeyRandomAsync()
             return Assert.ThrowsAsync<NotSupportedException>(() => wrapper.KeyRandomAsync());
         }
 
+        [Fact]
+        public void KeyRefCountAsync()
+        {
+            wrapper.KeyRefCountAsync("key", CommandFlags.None);
+            mock.Verify(_ => _.KeyRefCountAsync("prefix:key", CommandFlags.None));
+        }
+
         [Fact]
         public void KeyRenameAsync()
         {