RESP 3 support

src/StackExchange.Redis/CommandMap.cs

@@ -7,7 +7,7 @@ namespace StackExchange.Redis
     /// <summary>
     /// Represents the commands mapped on a particular configuration.
     /// </summary>
-    public sealed class CommandMap
+    public sealed class CommandMap // TODO: (RESP3) add HELLO command here?
     {
         private readonly CommandBytes[] map;
 

src/StackExchange.Redis/Configuration/DefaultOptionsProvider.cs

@@ -141,6 +141,11 @@ public static void AddProvider(DefaultOptionsProvider provider)
         /// </summary>
         public virtual TimeSpan KeepAliveInterval => TimeSpan.FromSeconds(60);
 
+        /// <summary>
+        /// Which Resp protocol to use (default is RESP 2).
+        /// </summary>
+        public virtual string Protocol => "2";
+
         /// <summary>
         /// Type of proxy to use (if any); for example <see cref="Proxy.Twemproxy"/>.
         /// </summary>

src/StackExchange.Redis/ConfigurationOptions.cs

@@ -85,6 +85,7 @@ internal const string
                 User = "user",
                 Password = "password",
                 PreserveAsyncOrder = "preserveAsyncOrder",
+                Protocol = "protocol",
                 Proxy = "proxy",
                 ResolveDns = "resolveDns",
                 ResponseTimeout = "responseTimeout",
@@ -116,6 +117,7 @@ internal const string
                 User,
                 Password,
                 PreserveAsyncOrder,
+                Protocol,
                 Proxy,
                 ResolveDns,
                 ServiceName,
@@ -144,7 +146,7 @@ public static string TryNormalize(string value)
         private bool? allowAdmin, abortOnConnectFail, resolveDns, ssl, checkCertificateRevocation,
                       includeDetailInExceptions, includePerformanceCountersInExceptions;
 
-        private string? tieBreaker, sslHost, configChannel;
+        private string? tieBreaker, sslHost, configChannel, protocol;
 
         private TimeSpan? heartbeatInterval;
 
@@ -449,6 +451,15 @@ public bool PreserveAsyncOrder
             set { }
         }
 
+        /// <summary>
+        /// Which Resp protocol to use (default is RESP 2).
+        /// </summary>
+        public string Protocol
+        {
+            get => protocol ?? Defaults.Protocol;
+            set => protocol = value;
+        }
+
         /// <summary>
         /// Type of proxy to use (if any); for example <see cref="Proxy.Twemproxy"/>.
         /// </summary>
@@ -632,6 +643,7 @@ public static ConfigurationOptions Parse(string configuration, bool ignoreUnknow
             configChannel = configChannel,
             abortOnConnectFail = abortOnConnectFail,
             resolveDns = resolveDns,
+            protocol = protocol,
             proxy = proxy,
             commandMap = commandMap,
             CertificateValidationCallback = CertificateValidationCallback,
@@ -727,6 +739,7 @@ public string ToString(bool includePassword)
             Append(sb, OptionKeys.ResolveDns, resolveDns);
             Append(sb, OptionKeys.ChannelPrefix, (string?)ChannelPrefix);
             Append(sb, OptionKeys.ConnectRetry, connectRetry);
+            Append(sb, OptionKeys.Protocol, protocol);
             Append(sb, OptionKeys.Proxy, proxy);
             Append(sb, OptionKeys.ConfigCheckSeconds, configCheckSeconds);
             Append(sb, OptionKeys.ResponseTimeout, responseTimeout);
@@ -874,6 +887,9 @@ private ConfigurationOptions DoParse(string configuration, bool ignoreUnknown)
                         case OptionKeys.SslHost:
                             SslHost = value;
                             break;
+                        case OptionKeys.Protocol:
+                            Protocol = value;
+                            break;
                         case OptionKeys.Proxy:
                             Proxy = OptionKeys.ParseProxy(key, value);
                             break;

src/StackExchange.Redis/ConnectionMultiplexer.cs

@@ -110,6 +110,11 @@ public bool IncludePerformanceCountersInExceptions
         /// </summary>
         public string Configuration => RawConfig.ToString();
 
+        /// <summary>
+        /// Gets the RESP protocol in use.
+        /// </summary>
+        public string Protocol => RawConfig.Protocol;
+
         /// <summary>
         /// Indicates whether any servers are connected.
         /// </summary>

src/StackExchange.Redis/Enums/RedisCommand.cs

@@ -64,6 +64,7 @@ internal enum RedisCommand
     GETSET,
 
     HDEL,
+    HELLO,
     HEXISTS,
     HGET,
     HGETALL,
@@ -279,6 +280,7 @@ internal static bool IsPrimaryOnly(this RedisCommand command)
             case RedisCommand.GETEX:
             case RedisCommand.GETSET:
             case RedisCommand.HDEL:
+            case RedisCommand.HELLO:
             case RedisCommand.HINCRBY:
             case RedisCommand.HINCRBYFLOAT:
             case RedisCommand.HMSET:

src/StackExchange.Redis/Interfaces/IConnectionMultiplexer.cs

@@ -34,6 +34,11 @@ public interface IConnectionMultiplexer : IDisposable, IAsyncDisposable
         /// </summary>
         string Configuration { get; }
 
+        /// <summary>
+        /// Gets the RESP protocol in use.
+        /// </summary>
+        public string Protocol { get; }
+
         /// <summary>
         /// Gets the timeout associated with the connections.
         /// </summary>

src/StackExchange.Redis/PublicAPI/PublicAPI.Shipped.txt

@@ -242,6 +242,8 @@ StackExchange.Redis.ConfigurationOptions.Password.get -> string?
 StackExchange.Redis.ConfigurationOptions.Password.set -> void
 StackExchange.Redis.ConfigurationOptions.PreserveAsyncOrder.get -> bool
 StackExchange.Redis.ConfigurationOptions.PreserveAsyncOrder.set -> void
+StackExchange.Redis.ConfigurationOptions.Protocol.get -> string!
+StackExchange.Redis.ConfigurationOptions.Protocol.set -> void
 StackExchange.Redis.ConfigurationOptions.Proxy.get -> StackExchange.Redis.Proxy
 StackExchange.Redis.ConfigurationOptions.Proxy.set -> void
 StackExchange.Redis.ConfigurationOptions.ReconnectRetryPolicy.get -> StackExchange.Redis.IReconnectRetryPolicy!
@@ -349,6 +351,7 @@ StackExchange.Redis.ConnectionMultiplexer.IsConnecting.get -> bool
 StackExchange.Redis.ConnectionMultiplexer.OperationCount.get -> long
 StackExchange.Redis.ConnectionMultiplexer.PreserveAsyncOrder.get -> bool
 StackExchange.Redis.ConnectionMultiplexer.PreserveAsyncOrder.set -> void
+StackExchange.Redis.ConnectionMultiplexer.Protocol.get -> string!
 StackExchange.Redis.ConnectionMultiplexer.PublishReconfigure(StackExchange.Redis.CommandFlags flags = StackExchange.Redis.CommandFlags.None) -> long
 StackExchange.Redis.ConnectionMultiplexer.PublishReconfigureAsync(StackExchange.Redis.CommandFlags flags = StackExchange.Redis.CommandFlags.None) -> System.Threading.Tasks.Task<long>!
 StackExchange.Redis.ConnectionMultiplexer.ReconfigureAsync(string! reason) -> System.Threading.Tasks.Task<bool>!
@@ -488,6 +491,7 @@ StackExchange.Redis.IConnectionMultiplexer.IsConnecting.get -> bool
 StackExchange.Redis.IConnectionMultiplexer.OperationCount.get -> long
 StackExchange.Redis.IConnectionMultiplexer.PreserveAsyncOrder.get -> bool
 StackExchange.Redis.IConnectionMultiplexer.PreserveAsyncOrder.set -> void
+StackExchange.Redis.IConnectionMultiplexer.Protocol.get -> string!
 StackExchange.Redis.IConnectionMultiplexer.PublishReconfigure(StackExchange.Redis.CommandFlags flags = StackExchange.Redis.CommandFlags.None) -> long
 StackExchange.Redis.IConnectionMultiplexer.PublishReconfigureAsync(StackExchange.Redis.CommandFlags flags = StackExchange.Redis.CommandFlags.None) -> System.Threading.Tasks.Task<long>!
 StackExchange.Redis.IConnectionMultiplexer.RegisterProfiler(System.Func<StackExchange.Redis.Profiling.ProfilingSession!>! profilingSessionProvider) -> void
@@ -1781,6 +1785,7 @@ virtual StackExchange.Redis.Configuration.DefaultOptionsProvider.IncludeDetailIn
 virtual StackExchange.Redis.Configuration.DefaultOptionsProvider.IncludePerformanceCountersInExceptions.get -> bool
 virtual StackExchange.Redis.Configuration.DefaultOptionsProvider.IsMatch(System.Net.EndPoint! endpoint) -> bool
 virtual StackExchange.Redis.Configuration.DefaultOptionsProvider.KeepAliveInterval.get -> System.TimeSpan
+virtual StackExchange.Redis.Configuration.DefaultOptionsProvider.Protocol.get -> string!
 virtual StackExchange.Redis.Configuration.DefaultOptionsProvider.Proxy.get -> StackExchange.Redis.Proxy
 virtual StackExchange.Redis.Configuration.DefaultOptionsProvider.ReconnectRetryPolicy.get -> StackExchange.Redis.IReconnectRetryPolicy?
 virtual StackExchange.Redis.Configuration.DefaultOptionsProvider.ResolveDns.get -> bool

src/StackExchange.Redis/ServerEndPoint.cs

@@ -931,6 +931,14 @@ private async Task HandshakeAsync(PhysicalConnection connection, LogProxy? log)
                 }
             }
 
+            if (Multiplexer.Protocol == "3")
+            {
+                log?.WriteLine($"{Format.ToString(this)}: Setting RESP protocol to RESP {Multiplexer.Protocol}");
+                msg = Message.Create(-1, CommandFlags.FireAndForget, RedisCommand.HELLO, (RedisValue)Multiplexer.Protocol);
+                msg.SetInternalCall();
+                await WriteDirectOrQueueFireAndForgetAsync(connection, msg, ResultProcessor.DemandOK).ForAwait();
+            }
+
             var bridge = connection.BridgeCouldBeNull;
             if (bridge == null)
             {

tests/StackExchange.Redis.Tests/ConfigTests.cs

@@ -458,6 +458,20 @@ public void ThreadPoolManagerIsDetected()
         Assert.Same(PipeScheduler.ThreadPool, conn.SocketManager?.Scheduler);
     }
 
+    [Fact]
+    public void Resp3Test()
+    {
+        var config = new ConfigurationOptions
+        {
+            Protocol = "3"
+        };
+
+        var conn = ConnectionMultiplexer.Connect(config);
+        var db = conn.GetDatabase();
+        db.Ping();
+        db.Ping();
+    }
+
     [Fact]
     public void DefaultThreadPoolManagerIsDetected()
     {

tests/StackExchange.Redis.Tests/Helpers/SharedConnectionFixture.cs

@@ -59,6 +59,8 @@ public bool IgnoreConnect
 
         public string Configuration => _inner.Configuration;
 
+        public string Protocol => _inner.Protocol;
+
         public int TimeoutMilliseconds => _inner.TimeoutMilliseconds;
 
         public long OperationCount => _inner.OperationCount;