Updated KeyExtractionFunc for all the modules

internal/acl/acl.go

@@ -410,8 +410,7 @@ func (acl *ACL) AuthorizeConnection(conn *net.Conn, cmd []string, command types.
 			return errors.New("not authorised to access any keys")
 		}
 
-		// 8. If @read is in the list of categories, check if keys are in IncludedReadKeys
+		// 8. Check if readKeys are in IncludedReadKeys
-		if slices.Contains(categories, constants.ReadCategory) {
 		if !slices.ContainsFunc(readKeys, func(key string) bool {
 			return slices.ContainsFunc(connection.User.IncludedReadKeys, func(readKeyGlob string) bool {
 				if acl.GlobPatterns[readKeyGlob].Match(key) {
@@ -423,10 +422,8 @@ func (acl *ACL) AuthorizeConnection(conn *net.Conn, cmd []string, command types.
 		}) {
 			return fmt.Errorf("not authorised to access the following keys %+v", notAllowed)
 		}
-		}
 
-		// 9. If @write is in the list of categories, check if keys are in IncludedWriteKeys
+		// 9. Check if keys are in IncludedWriteKeys
-		if slices.Contains(categories, constants.WriteCategory) {
 		if !slices.ContainsFunc(writeKeys, func(key string) bool {
 			return slices.ContainsFunc(connection.User.IncludedWriteKeys, func(writeKeyGlob string) bool {
 				if acl.GlobPatterns[writeKeyGlob].Match(key) {
@@ -439,7 +436,6 @@ func (acl *ACL) AuthorizeConnection(conn *net.Conn, cmd []string, command types.
 			return fmt.Errorf("not authorised to access the following keys %+v", notAllowed)
 		}
 	}
-	}
 
 	return nil
 }

pkg/modules/acl/commands.go

@@ -498,8 +498,12 @@ func Commands() []types.Command {
 			Categories:  []string{constants.ConnectionCategory, constants.SlowCategory},
 			Description: "(AUTH [username] password) Authenticates the connection",
 			Sync:        false,
-			KeyExtractionFunc: func(cmd []string) ([]string, error) {
+			KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
-				return []string{}, nil
+				return types.AccessKeys{
+					Channels:  make([]string, 0),
+					ReadKeys:  make([]string, 0),
+					WriteKeys: make([]string, 0),
+				}, nil
 			},
 			HandlerFunc: handleAuth,
 		},
@@ -509,8 +513,12 @@ func Commands() []types.Command {
 			Categories:  []string{},
 			Description: "Access-Control-List commands",
 			Sync:        false,
-			KeyExtractionFunc: func(cmd []string) ([]string, error) {
+			KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
-				return []string{}, nil
+				return types.AccessKeys{
+					Channels:  make([]string, 0),
+					ReadKeys:  make([]string, 0),
+					WriteKeys: make([]string, 0),
+				}, nil
 			},
 			SubCommands: []types.SubCommand{
 				{
@@ -520,8 +528,12 @@ func Commands() []types.Command {
 					Description: `(ACL CAT [category]) List all the categories. 
 If the optional category is provided, list all the commands in the category`,
 					Sync: false,
-					KeyExtractionFunc: func(cmd []string) ([]string, error) {
+					KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
-						return []string{}, nil
+						return types.AccessKeys{
+							Channels:  make([]string, 0),
+							ReadKeys:  make([]string, 0),
+							WriteKeys: make([]string, 0),
+						}, nil
 					},
 					HandlerFunc: handleCat,
 				},
@@ -531,8 +543,12 @@ If the optional category is provided, list all the commands in the category`,
 					Categories:  []string{constants.AdminCategory, constants.SlowCategory, constants.DangerousCategory},
 					Description: "(ACL USERS) List all usernames of the configured ACL users",
 					Sync:        false,
-					KeyExtractionFunc: func(cmd []string) ([]string, error) {
+					KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
-						return []string{}, nil
+						return types.AccessKeys{
+							Channels:  make([]string, 0),
+							ReadKeys:  make([]string, 0),
+							WriteKeys: make([]string, 0),
+						}, nil
 					},
 					HandlerFunc: handleUsers,
 				},
@@ -542,8 +558,12 @@ If the optional category is provided, list all the commands in the category`,
 					Categories:  []string{constants.AdminCategory, constants.SlowCategory, constants.DangerousCategory},
 					Description: "(ACL SETUSER) Configure a new or existing user",
 					Sync:        true,
-					KeyExtractionFunc: func(cmd []string) ([]string, error) {
+					KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
-						return []string{}, nil
+						return types.AccessKeys{
+							Channels:  make([]string, 0),
+							ReadKeys:  make([]string, 0),
+							WriteKeys: make([]string, 0),
+						}, nil
 					},
 					HandlerFunc: handleSetUser,
 				},
@@ -553,8 +573,12 @@ If the optional category is provided, list all the commands in the category`,
 					Categories:  []string{constants.AdminCategory, constants.SlowCategory, constants.DangerousCategory},
 					Description: "(ACL GETUSER username) List the ACL rules of a user",
 					Sync:        false,
-					KeyExtractionFunc: func(cmd []string) ([]string, error) {
+					KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
-						return []string{}, nil
+						return types.AccessKeys{
+							Channels:  make([]string, 0),
+							ReadKeys:  make([]string, 0),
+							WriteKeys: make([]string, 0),
+						}, nil
 					},
 					HandlerFunc: handleGetUser,
 				},
@@ -564,8 +588,12 @@ If the optional category is provided, list all the commands in the category`,
 					Categories:  []string{constants.AdminCategory, constants.SlowCategory, constants.DangerousCategory},
 					Description: "(ACL DELUSER username [username ...]) Deletes users and terminates their connections. Cannot delete default user",
 					Sync:        true,
-					KeyExtractionFunc: func(cmd []string) ([]string, error) {
+					KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
-						return []string{}, nil
+						return types.AccessKeys{
+							Channels:  make([]string, 0),
+							ReadKeys:  make([]string, 0),
+							WriteKeys: make([]string, 0),
+						}, nil
 					},
 					HandlerFunc: handleDelUser,
 				},
@@ -575,8 +603,12 @@ If the optional category is provided, list all the commands in the category`,
 					Categories:  []string{constants.FastCategory},
 					Description: "(ACL WHOAMI) Returns the authenticated user of the current connection",
 					Sync:        true,
-					KeyExtractionFunc: func(cmd []string) ([]string, error) {
+					KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
-						return []string{}, nil
+						return types.AccessKeys{
+							Channels:  make([]string, 0),
+							ReadKeys:  make([]string, 0),
+							WriteKeys: make([]string, 0),
+						}, nil
 					},
 					HandlerFunc: handleWhoAmI,
 				},
@@ -586,8 +618,12 @@ If the optional category is provided, list all the commands in the category`,
 					Categories:  []string{constants.AdminCategory, constants.SlowCategory, constants.DangerousCategory},
 					Description: "(ACL LIST) Dumps effective acl rules in acl config file format",
 					Sync:        true,
-					KeyExtractionFunc: func(cmd []string) ([]string, error) {
+					KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
-						return []string{}, nil
+						return types.AccessKeys{
+							Channels:  make([]string, 0),
+							ReadKeys:  make([]string, 0),
+							WriteKeys: make([]string, 0),
+						}, nil
 					},
 					HandlerFunc: handleList,
 				},
@@ -600,8 +636,12 @@ If the optional category is provided, list all the commands in the category`,
 When 'MERGE' is passed, users from config file who share a username with users in memory will be merged.
 When 'REPLACE' is passed, users from config file who share a username with users in memory will replace the user in memory.`,
 					Sync: true,
-					KeyExtractionFunc: func(cmd []string) ([]string, error) {
+					KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
-						return []string{}, nil
+						return types.AccessKeys{
+							Channels:  make([]string, 0),
+							ReadKeys:  make([]string, 0),
+							WriteKeys: make([]string, 0),
+						}, nil
 					},
 					HandlerFunc: handleLoad,
 				},
@@ -611,8 +651,12 @@ When 'REPLACE' is passed, users from config file who share a username with users
 					Categories:  []string{constants.AdminCategory, constants.SlowCategory, constants.DangerousCategory},
 					Description: "(ACL SAVE) Saves the effective ACL rules the configured ACL config file",
 					Sync:        true,
-					KeyExtractionFunc: func(cmd []string) ([]string, error) {
+					KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
-						return []string{}, nil
+						return types.AccessKeys{
+							Channels:  make([]string, 0),
+							ReadKeys:  make([]string, 0),
+							WriteKeys: make([]string, 0),
+						}, nil
 					},
 					HandlerFunc: handleSave,
 				},

pkg/modules/admin/commands.go

@@ -26,7 +26,7 @@ import (
 	"strings"
 )
 
-func handleGetAllCommands(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
+func handleGetAllCommands(_ context.Context, _ []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	commands := server.GetAllCommands()
 
 	res := ""
@@ -199,7 +199,13 @@ func Commands() []types.Command {
 			Categories:  []string{constants.AdminCategory, constants.SlowCategory},
 			Description: "Get a list of all the commands in available on the echovault with categories and descriptions",
 			Sync:        false,
-			KeyExtractionFunc: func(cmd []string) ([]string, error) { return []string{}, nil },
+			KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
+				return types.AccessKeys{
+					Channels:  make([]string, 0),
+					ReadKeys:  make([]string, 0),
+					WriteKeys: make([]string, 0),
+				}, nil
+			},
 			HandlerFunc: handleGetAllCommands,
 		},
 		{
@@ -208,8 +214,12 @@ func Commands() []types.Command {
 			Categories:  []string{},
 			Description: "Commands pertaining to echovault commands",
 			Sync:        false,
-			KeyExtractionFunc: func(cmd []string) ([]string, error) {
+			KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
-				return []string{}, nil
+				return types.AccessKeys{
+					Channels:  make([]string, 0),
+					ReadKeys:  make([]string, 0),
+					WriteKeys: make([]string, 0),
+				}, nil
 			},
 			SubCommands: []types.SubCommand{
 				{
@@ -218,7 +228,13 @@ func Commands() []types.Command {
 					Categories:  []string{constants.SlowCategory, constants.ConnectionCategory},
 					Description: "Get command documentation",
 					Sync:        false,
-					KeyExtractionFunc: func(cmd []string) ([]string, error) { return []string{}, nil },
+					KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
+						return types.AccessKeys{
+							Channels:  make([]string, 0),
+							ReadKeys:  make([]string, 0),
+							WriteKeys: make([]string, 0),
+						}, nil
+					},
 					HandlerFunc: handleCommandDocs,
 				},
 				{
@@ -227,7 +243,13 @@ func Commands() []types.Command {
 					Categories:  []string{constants.SlowCategory},
 					Description: "Get the dumber of commands in the echovault",
 					Sync:        false,
-					KeyExtractionFunc: func(cmd []string) ([]string, error) { return []string{}, nil },
+					KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
+						return types.AccessKeys{
+							Channels:  make([]string, 0),
+							ReadKeys:  make([]string, 0),
+							WriteKeys: make([]string, 0),
+						}, nil
+					},
 					HandlerFunc: handleCommandCount,
 				},
 				{
@@ -237,7 +259,13 @@ func Commands() []types.Command {
 					Description: `(COMMAND LIST [FILTERBY <ACLCAT category | PATTERN pattern | MODULE module>]) Get the list of command names.
 Allows for filtering by ACL category or glob pattern.`,
 					Sync: false,
-					KeyExtractionFunc: func(cmd []string) ([]string, error) { return []string{}, nil },
+					KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
+						return types.AccessKeys{
+							Channels:  make([]string, 0),
+							ReadKeys:  make([]string, 0),
+							WriteKeys: make([]string, 0),
+						}, nil
+					},
 					HandlerFunc: handleCommandList,
 				},
 			},
@@ -248,8 +276,12 @@ Allows for filtering by ACL category or glob pattern.`,
 			Categories:  []string{constants.AdminCategory, constants.SlowCategory, constants.DangerousCategory},
 			Description: "(SAVE) Trigger a snapshot save",
 			Sync:        true,
-			KeyExtractionFunc: func(cmd []string) ([]string, error) {
+			KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
-				return []string{}, nil
+				return types.AccessKeys{
+					Channels:  make([]string, 0),
+					ReadKeys:  make([]string, 0),
+					WriteKeys: make([]string, 0),
+				}, nil
 			},
 			HandlerFunc: func(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
 				if err := server.TakeSnapshot(); err != nil {
@@ -264,8 +296,12 @@ Allows for filtering by ACL category or glob pattern.`,
 			Categories:  []string{constants.AdminCategory, constants.FastCategory, constants.DangerousCategory},
 			Description: "(LASTSAVE) Get unix timestamp for the latest snapshot in milliseconds.",
 			Sync:        false,
-			KeyExtractionFunc: func(cmd []string) ([]string, error) {
+			KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
-				return []string{}, nil
+				return types.AccessKeys{
+					Channels:  make([]string, 0),
+					ReadKeys:  make([]string, 0),
+					WriteKeys: make([]string, 0),
+				}, nil
 			},
 			HandlerFunc: func(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
 				msec := server.GetLatestSnapshotTime()
@@ -281,8 +317,12 @@ Allows for filtering by ACL category or glob pattern.`,
 			Categories:  []string{constants.AdminCategory, constants.SlowCategory, constants.DangerousCategory},
 			Description: "(REWRITEAOF) Trigger re-writing of append process",
 			Sync:        false,
-			KeyExtractionFunc: func(cmd []string) ([]string, error) {
+			KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
-				return []string{}, nil
+				return types.AccessKeys{
+					Channels:  make([]string, 0),
+					ReadKeys:  make([]string, 0),
+					WriteKeys: make([]string, 0),
+				}, nil
 			},
 			HandlerFunc: func(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
 				if err := server.RewriteAOF(); err != nil {

pkg/modules/connection/commands.go

@@ -42,8 +42,12 @@ func Commands() []types.Command {
 			Categories:  []string{constants.FastCategory, constants.ConnectionCategory},
 			Description: "(PING [value]) Ping the echovault. If a value is provided, the value will be echoed.",
 			Sync:        false,
-			KeyExtractionFunc: func(cmd []string) ([]string, error) {
+			KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
-				return []string{}, nil
+				return types.AccessKeys{
+					Channels:  make([]string, 0),
+					ReadKeys:  make([]string, 0),
+					WriteKeys: make([]string, 0),
+				}, nil
 			},
 			HandlerFunc: handlePing,
 		},

pkg/modules/generic/commands.go

@@ -39,7 +39,7 @@ func handleSet(ctx context.Context, cmd []string, server types.EchoVault, _ *net
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 	value := cmd[2]
 	res := []byte(constants.OkResponse)
 	clock := server.GetClock()
@@ -99,7 +99,8 @@ func handleSet(ctx context.Context, cmd []string, server types.EchoVault, _ *net
 }
 
 func handleMSet(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
-	if _, err := msetKeyFunc(cmd); err != nil {
+	_, err := msetKeyFunc(cmd)
+	if err != nil {
 		return nil, err
 	}
 
@@ -159,7 +160,7 @@ func handleGet(ctx context.Context, cmd []string, server types.EchoVault, _ *net
 	if err != nil {
 		return nil, err
 	}
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	if !server.KeyExists(ctx, key) {
 		return []byte("$-1\r\n"), nil
@@ -185,7 +186,7 @@ func handleMGet(ctx context.Context, cmd []string, server types.EchoVault, _ *ne
 	values := make(map[string]string)
 
 	locks := make(map[string]bool)
-	for _, key := range keys {
+	for _, key := range keys.ReadKeys {
 		if _, ok := values[key]; ok {
 			// Skip if we have already locked this key
 			continue
@@ -232,7 +233,7 @@ func handleDel(ctx context.Context, cmd []string, server types.EchoVault, _ *net
 		return nil, err
 	}
 	count := 0
-	for _, key := range keys {
+	for _, key := range keys.WriteKeys {
 		err = server.DeleteKey(ctx, key)
 		if err != nil {
 			log.Printf("could not delete key %s due to error: %+v\n", key, err)
@@ -249,7 +250,7 @@ func handlePersist(ctx context.Context, cmd []string, server types.EchoVault, _
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 
 	if !server.KeyExists(ctx, key) {
 		return []byte(":0\r\n"), nil
@@ -276,7 +277,7 @@ func handleExpireTime(ctx context.Context, cmd []string, server types.EchoVault,
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	if !server.KeyExists(ctx, key) {
 		return []byte(":-2\r\n"), nil
@@ -307,7 +308,7 @@ func handleTTL(ctx context.Context, cmd []string, server types.EchoVault, _ *net
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	clock := server.GetClock()
 
@@ -344,7 +345,7 @@ func handleExpire(ctx context.Context, cmd []string, server types.EchoVault, _ *
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 
 	// Extract time
 	n, err := strconv.ParseInt(cmd[2], 10, 64)
@@ -412,7 +413,7 @@ func handleExpireAt(ctx context.Context, cmd []string, server types.EchoVault, _
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 
 	// Extract time
 	n, err := strconv.ParseInt(cmd[2], 10, 64)

pkg/modules/generic/key_funcs.go

@@ -17,18 +17,23 @@ package generic
 import (
 	"errors"
 	"github.com/echovault/echovault/pkg/constants"
+	"github.com/echovault/echovault/pkg/types"
 )
 
-func setKeyFunc(cmd []string) ([]string, error) {
+func setKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 || len(cmd) > 7 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func msetKeyFunc(cmd []string) ([]string, error) {
+func msetKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd[1:])%2 != 0 {
-		return nil, errors.New("each key must be paired with a value")
+		return types.AccessKeys{}, errors.New("each key must be paired with a value")
 	}
 	var keys []string
 	for i, key := range cmd[1:] {
@@ -36,61 +41,97 @@ func msetKeyFunc(cmd []string) ([]string, error) {
 			keys = append(keys, key)
 		}
 	}
-	return keys, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: keys,
+	}, nil
 }
 
-func getKeyFunc(cmd []string) ([]string, error) {
+func getKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func mgetKeyFunc(cmd []string) ([]string, error) {
+func mgetKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func delKeyFunc(cmd []string) ([]string, error) {
+func delKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:],
+	}, nil
 }
 
-func persistKeyFunc(cmd []string) ([]string, error) {
+func persistKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:],
+	}, nil
 }
 
-func expireTimeKeyFunc(cmd []string) ([]string, error) {
+func expireTimeKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func ttlKeyFunc(cmd []string) ([]string, error) {
+func ttlKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func expireKeyFunc(cmd []string) ([]string, error) {
+func expireKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 || len(cmd) > 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func expireAtKeyFunc(cmd []string) ([]string, error) {
+func expireAtKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 || len(cmd) > 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }

pkg/modules/hash/commands.go

@@ -34,7 +34,7 @@ func handleHSET(ctx context.Context, cmd []string, server types.EchoVault, _ *ne
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 	entries := make(map[string]interface{})
 
 	if len(cmd[2:])%2 != 0 {
@@ -92,7 +92,7 @@ func handleHGET(ctx context.Context, cmd []string, server types.EchoVault, _ *ne
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 	fields := cmd[2:]
 
 	if !server.KeyExists(ctx, key) {
@@ -143,7 +143,7 @@ func handleHSTRLEN(ctx context.Context, cmd []string, server types.EchoVault, _
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 	fields := cmd[2:]
 
 	if !server.KeyExists(ctx, key) {
@@ -194,7 +194,7 @@ func handleHVALS(ctx context.Context, cmd []string, server types.EchoVault, _ *n
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	if !server.KeyExists(ctx, key) {
 		return []byte("*0\r\n"), nil
@@ -235,7 +235,7 @@ func handleHRANDFIELD(ctx context.Context, cmd []string, server types.EchoVault,
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	count := 1
 	if len(cmd) >= 3 {
@@ -351,7 +351,7 @@ func handleHLEN(ctx context.Context, cmd []string, server types.EchoVault, _ *ne
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	if !server.KeyExists(ctx, key) {
 		return []byte(":0\r\n"), nil
@@ -376,7 +376,7 @@ func handleHKEYS(ctx context.Context, cmd []string, server types.EchoVault, _ *n
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	if !server.KeyExists(ctx, key) {
 		return []byte("*0\r\n"), nil
@@ -406,7 +406,7 @@ func handleHINCRBY(ctx context.Context, cmd []string, server types.EchoVault, _
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 	field := cmd[2]
 
 	var intIncrement int
@@ -498,7 +498,7 @@ func handleHGETALL(ctx context.Context, cmd []string, server types.EchoVault, _
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	if !server.KeyExists(ctx, key) {
 		return []byte("*0\r\n"), nil
@@ -538,7 +538,7 @@ func handleHEXISTS(ctx context.Context, cmd []string, server types.EchoVault, _
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 	field := cmd[2]
 
 	if !server.KeyExists(ctx, key) {
@@ -568,7 +568,7 @@ func handleHDEL(ctx context.Context, cmd []string, server types.EchoVault, _ *ne
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 	fields := cmd[2:]
 
 	if !server.KeyExists(ctx, key) {

pkg/modules/hash/key_funcs.go

@@ -17,91 +17,144 @@ package hash
 import (
 	"errors"
 	"github.com/echovault/echovault/pkg/constants"
+	"github.com/echovault/echovault/pkg/types"
 )
 
-func hsetKeyFunc(cmd []string) ([]string, error) {
+func hsetKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func hsetnxKeyFunc(cmd []string) ([]string, error) {
+func hsetnxKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func hgetKeyFunc(cmd []string) ([]string, error) {
+func hgetKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func hstrlenKeyFunc(cmd []string) ([]string, error) {
+func hstrlenKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func hvalsKeyFunc(cmd []string) ([]string, error) {
+func hvalsKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func hrandfieldKeyFunc(cmd []string) ([]string, error) {
+func hrandfieldKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 2 || len(cmd) > 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
 	if len(cmd) == 2 {
-		return cmd[1:], nil
+		return types.AccessKeys{
+			Channels:  make([]string, 0),
+			ReadKeys:  cmd[1:],
+			WriteKeys: make([]string, 0),
+		}, nil
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func hlenKeyFunc(cmd []string) ([]string, error) {
+func hlenKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func hkeysKeyFunc(cmd []string) ([]string, error) {
+func hkeysKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func hincrbyKeyFunc(cmd []string) ([]string, error) {
+func hincrbyKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func hgetallKeyFunc(cmd []string) ([]string, error) {
+func hgetallKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func hexistsKeyFunc(cmd []string) ([]string, error) {
+func hexistsKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func hdelKeyFunc(cmd []string) ([]string, error) {
+func hdelKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }

pkg/modules/list/commands.go

@@ -33,7 +33,7 @@ func handleLLen(ctx context.Context, cmd []string, server types.EchoVault, _ *ne
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	if !server.KeyExists(ctx, key) {
 		// If key does not exist, return 0
@@ -52,13 +52,13 @@ func handleLLen(ctx context.Context, cmd []string, server types.EchoVault, _ *ne
 	return nil, errors.New("LLEN command on non-list item")
 }
 
-func handleLIndex(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleLIndex(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := lindexKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 	index, ok := internal.AdaptType(cmd[2]).(int)
 
 	if !ok {
@@ -86,13 +86,13 @@ func handleLIndex(ctx context.Context, cmd []string, server types.EchoVault, con
 	return []byte(fmt.Sprintf("+%s\r\n", list[index])), nil
 }
 
-func handleLRange(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleLRange(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := lrangeKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 	start, startOk := internal.AdaptType(cmd[2]).(int)
 	end, endOk := internal.AdaptType(cmd[3]).(int)
 
@@ -165,13 +165,13 @@ func handleLRange(ctx context.Context, cmd []string, server types.EchoVault, con
 	return bytes, nil
 }
 
-func handleLSet(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleLSet(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := lsetKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 
 	index, ok := internal.AdaptType(cmd[2]).(int)
 	if !ok {
@@ -204,13 +204,13 @@ func handleLSet(ctx context.Context, cmd []string, server types.EchoVault, conn
 	return []byte(constants.OkResponse), nil
 }
 
-func handleLTrim(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleLTrim(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := ltrimKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 	start, startOk := internal.AdaptType(cmd[2]).(int)
 	end, endOk := internal.AdaptType(cmd[3]).(int)
 
@@ -253,13 +253,13 @@ func handleLTrim(ctx context.Context, cmd []string, server types.EchoVault, conn
 	return []byte(constants.OkResponse), nil
 }
 
-func handleLRem(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleLRem(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := lremKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 	value := cmd[3]
 
 	count, ok := internal.AdaptType(cmd[2]).(int)
@@ -321,14 +321,13 @@ func handleLRem(ctx context.Context, cmd []string, server types.EchoVault, conn
 	return []byte(constants.OkResponse), nil
 }
 
-func handleLMove(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleLMove(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := lmoveKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	source := keys[0]
+	source, destination := keys.WriteKeys[0], keys.WriteKeys[1]
-	destination := keys[1]
 	whereFrom := strings.ToLower(cmd[3])
 	whereTo := strings.ToLower(cmd[4])
 
@@ -394,7 +393,7 @@ func handleLPush(ctx context.Context, cmd []string, server types.EchoVault, _ *n
 		newElems = append(newElems, internal.AdaptType(elem))
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 
 	if !server.KeyExists(ctx, key) {
 		switch strings.ToLower(cmd[0]) {
@@ -428,13 +427,13 @@ func handleLPush(ctx context.Context, cmd []string, server types.EchoVault, _ *n
 	return []byte(constants.OkResponse), nil
 }
 
-func handleRPush(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleRPush(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := rpushKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 
 	var newElems []interface{}
 
@@ -482,7 +481,7 @@ func handlePop(ctx context.Context, cmd []string, server types.EchoVault, _ *net
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 
 	if !server.KeyExists(ctx, key) {
 		return nil, fmt.Errorf("%s command on non-list item", strings.ToUpper(cmd[0]))

pkg/modules/list/key_funcs.go

@@ -17,74 +17,115 @@ package list
 import (
 	"errors"
 	"github.com/echovault/echovault/pkg/constants"
+	"github.com/echovault/echovault/pkg/types"
 )
 
-func lpushKeyFunc(cmd []string) ([]string, error) {
+func lpushKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func popKeyFunc(cmd []string) ([]string, error) {
+func popKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:],
+	}, nil
 }
 
-func llenKeyFunc(cmd []string) ([]string, error) {
+func llenKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func lrangeKeyFunc(cmd []string) ([]string, error) {
+func lrangeKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func lindexKeyFunc(cmd []string) ([]string, error) {
+func lindexKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func lsetKeyFunc(cmd []string) ([]string, error) {
+func lsetKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func ltrimKeyFunc(cmd []string) ([]string, error) {
+func ltrimKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func lremKeyFunc(cmd []string) ([]string, error) {
+func lremKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func rpushKeyFunc(cmd []string) ([]string, error) {
+func rpushKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func lmoveKeyFunc(cmd []string) ([]string, error) {
+func lmoveKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 5 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1], cmd[2]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:3],
+	}, nil
 }

pkg/modules/pubsub/commands.go

@@ -111,12 +111,16 @@ func Commands() []types.Command {
 			Categories:  []string{constants.PubSubCategory, constants.ConnectionCategory, constants.SlowCategory},
 			Description: "(SUBSCRIBE channel [channel ...]) Subscribe to one or more channels.",
 			Sync:        false,
-			KeyExtractionFunc: func(cmd []string) ([]string, error) {
+			KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
 				// Treat the channels as keys
 				if len(cmd) < 2 {
-					return nil, errors.New(constants.WrongArgsResponse)
+					return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 				}
-				return cmd[1:], nil
+				return types.AccessKeys{
+					Channels:  cmd[1:],
+					ReadKeys:  make([]string, 0),
+					WriteKeys: make([]string, 0),
+				}, nil
 			},
 			HandlerFunc: handleSubscribe,
 		},
@@ -126,12 +130,16 @@ func Commands() []types.Command {
 			Categories:  []string{constants.PubSubCategory, constants.ConnectionCategory, constants.SlowCategory},
 			Description: "(PSUBSCRIBE pattern [pattern ...]) Subscribe to one or more glob patterns.",
 			Sync:        false,
-			KeyExtractionFunc: func(cmd []string) ([]string, error) {
+			KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
 				// Treat the patterns as keys
 				if len(cmd) < 2 {
-					return nil, errors.New(constants.WrongArgsResponse)
+					return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 				}
-				return cmd[1:], nil
+				return types.AccessKeys{
+					Channels:  cmd[1:],
+					ReadKeys:  make([]string, 0),
+					WriteKeys: make([]string, 0),
+				}, nil
 			},
 			HandlerFunc: handleSubscribe,
 		},
@@ -141,12 +149,16 @@ func Commands() []types.Command {
 			Categories:  []string{constants.PubSubCategory, constants.FastCategory},
 			Description: "(PUBLISH channel message) Publish a message to the specified channel.",
 			Sync:        true,
-			KeyExtractionFunc: func(cmd []string) ([]string, error) {
+			KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
 				// Treat the channel as a key
 				if len(cmd) != 3 {
-					return nil, errors.New(constants.WrongArgsResponse)
+					return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 				}
-				return []string{cmd[1]}, nil
+				return types.AccessKeys{
+					Channels:  cmd[1:2],
+					ReadKeys:  make([]string, 0),
+					WriteKeys: make([]string, 0),
+				}, nil
 			},
 			HandlerFunc: handlePublish,
 		},
@@ -158,9 +170,13 @@ func Commands() []types.Command {
 If the channel list is not provided, then the connection will be unsubscribed from all the channels that
 it's currently subscribe to.`,
 			Sync: false,
-			KeyExtractionFunc: func(cmd []string) ([]string, error) {
+			KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
 				// Treat the channels as keys
-				return cmd[1:], nil
+				return types.AccessKeys{
+					Channels:  cmd[1:],
+					ReadKeys:  make([]string, 0),
+					WriteKeys: make([]string, 0),
+				}, nil
 			},
 			HandlerFunc: handleUnsubscribe,
 		},
@@ -172,9 +188,12 @@ it's currently subscribe to.`,
 If the pattern list is not provided, then the connection will be unsubscribed from all the patterns that
 it's currently subscribe to.`,
 			Sync: false,
-			KeyExtractionFunc: func(cmd []string) ([]string, error) {
+			KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
-				// Treat the channels as keys
+				return types.AccessKeys{
-				return cmd[1:], nil
+					Channels:  cmd[1:],
+					ReadKeys:  make([]string, 0),
+					WriteKeys: make([]string, 0),
+				}, nil
 			},
 			HandlerFunc: handleUnsubscribe,
 		},
@@ -184,7 +203,13 @@ it's currently subscribe to.`,
 			Categories:  []string{},
 			Description: "",
 			Sync:        false,
-			KeyExtractionFunc: func(cmd []string) ([]string, error) { return []string{}, nil },
+			KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
+				return types.AccessKeys{
+					Channels:  make([]string, 0),
+					ReadKeys:  make([]string, 0),
+					WriteKeys: make([]string, 0),
+				}, nil
+			},
 			HandlerFunc: func(_ context.Context, _ []string, _ types.EchoVault, _ *net.Conn) ([]byte, error) {
 				return nil, errors.New("provide CHANNELS, NUMPAT, or NUMSUB subcommand")
 			},
@@ -197,7 +222,13 @@ it's currently subscribe to.`,
 match the given pattern. If no pattern is provided, all active channels are returned. Active channels are 
 channels with 1 or more subscribers.`,
 					Sync: false,
-					KeyExtractionFunc: func(cmd []string) ([]string, error) { return []string{}, nil },
+					KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
+						return types.AccessKeys{
+							Channels:  make([]string, 0),
+							ReadKeys:  make([]string, 0),
+							WriteKeys: make([]string, 0),
+						}, nil
+					},
 					HandlerFunc: handlePubSubChannels,
 				},
 				{
@@ -206,7 +237,13 @@ channels with 1 or more subscribers.`,
 					Categories:  []string{constants.PubSubCategory, constants.SlowCategory},
 					Description: `(PUBSUB NUMPAT) Return the number of patterns that are currently subscribed to by clients.`,
 					Sync:        false,
-					KeyExtractionFunc: func(cmd []string) ([]string, error) { return []string{}, nil },
+					KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
+						return types.AccessKeys{
+							Channels:  make([]string, 0),
+							ReadKeys:  make([]string, 0),
+							WriteKeys: make([]string, 0),
+						}, nil
+					},
 					HandlerFunc: handlePubSubNumPat,
 				},
 				{
@@ -216,7 +253,13 @@ channels with 1 or more subscribers.`,
 					Description: `(PUBSUB NUMSUB [channel [channel ...]]) Return an array of arrays containing the provided
 channel name and how many clients are currently subscribed to the channel.`,
 					Sync: false,
-					KeyExtractionFunc: func(cmd []string) ([]string, error) { return cmd[2:], nil },
+					KeyExtractionFunc: func(cmd []string) (types.AccessKeys, error) {
+						return types.AccessKeys{
+							Channels:  cmd[2:],
+							ReadKeys:  make([]string, 0),
+							WriteKeys: make([]string, 0),
+						}, nil
+					},
 					HandlerFunc: handlePubSubNumSubs,
 				},
 			},

pkg/modules/set/commands.go

@@ -27,13 +27,13 @@ import (
 	"strings"
 )
 
-func handleSADD(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleSADD(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := saddKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 
 	var set *internal_set.Set
 
@@ -64,13 +64,13 @@ func handleSADD(ctx context.Context, cmd []string, server types.EchoVault, conn
 	return []byte(fmt.Sprintf(":%d\r\n", count)), nil
 }
 
-func handleSCARD(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleSCARD(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := scardKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	if !server.KeyExists(ctx, key) {
 		return []byte(fmt.Sprintf(":0\r\n")), nil
@@ -91,23 +91,23 @@ func handleSCARD(ctx context.Context, cmd []string, server types.EchoVault, conn
 	return []byte(fmt.Sprintf(":%d\r\n", cardinality)), nil
 }
 
-func handleSDIFF(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleSDIFF(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := sdiffKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
 	// Extract base set first
-	if !server.KeyExists(ctx, keys[0]) {
+	if !server.KeyExists(ctx, keys.ReadKeys[0]) {
-		return nil, fmt.Errorf("key for base set \"%s\" does not exist", keys[0])
+		return nil, fmt.Errorf("key for base set \"%s\" does not exist", keys.ReadKeys[0])
 	}
-	if _, err = server.KeyRLock(ctx, keys[0]); err != nil {
+	if _, err = server.KeyRLock(ctx, keys.ReadKeys[0]); err != nil {
 		return nil, err
 	}
-	defer server.KeyRUnlock(ctx, keys[0])
+	defer server.KeyRUnlock(ctx, keys.ReadKeys[0])
-	baseSet, ok := server.GetValue(ctx, keys[0]).(*internal_set.Set)
+	baseSet, ok := server.GetValue(ctx, keys.ReadKeys[0]).(*internal_set.Set)
 	if !ok {
-		return nil, fmt.Errorf("value at key %s is not a set", keys[0])
+		return nil, fmt.Errorf("value at key %s is not a set", keys.ReadKeys[0])
 	}
 
 	locks := make(map[string]bool)
@@ -119,7 +119,7 @@ func handleSDIFF(ctx context.Context, cmd []string, server types.EchoVault, conn
 		}
 	}()
 
-	for _, key := range keys[1:] {
+	for _, key := range keys.ReadKeys[1:] {
 		if !server.KeyExists(ctx, key) {
 			continue
 		}
@@ -152,25 +152,25 @@ func handleSDIFF(ctx context.Context, cmd []string, server types.EchoVault, conn
 	return []byte(res), nil
 }
 
-func handleSDIFFSTORE(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleSDIFFSTORE(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := sdiffstoreKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	destination := keys[0]
+	destination := keys.WriteKeys[0]
 
 	// Extract base set first
-	if !server.KeyExists(ctx, keys[1]) {
+	if !server.KeyExists(ctx, keys.ReadKeys[0]) {
-		return nil, fmt.Errorf("key for base set \"%s\" does not exist", keys[1])
+		return nil, fmt.Errorf("key for base set \"%s\" does not exist", keys.ReadKeys[0])
 	}
-	if _, err := server.KeyRLock(ctx, keys[1]); err != nil {
+	if _, err := server.KeyRLock(ctx, keys.ReadKeys[0]); err != nil {
 		return nil, err
 	}
-	defer server.KeyRUnlock(ctx, keys[1])
+	defer server.KeyRUnlock(ctx, keys.ReadKeys[0])
-	baseSet, ok := server.GetValue(ctx, keys[1]).(*internal_set.Set)
+	baseSet, ok := server.GetValue(ctx, keys.ReadKeys[0]).(*internal_set.Set)
 	if !ok {
-		return nil, fmt.Errorf("value at key %s is not a set", keys[1])
+		return nil, fmt.Errorf("value at key %s is not a set", keys.ReadKeys[0])
 	}
 
 	locks := make(map[string]bool)
@@ -182,7 +182,7 @@ func handleSDIFFSTORE(ctx context.Context, cmd []string, server types.EchoVault,
 		}
 	}()
 
-	for _, key := range keys[2:] {
+	for _, key := range keys.ReadKeys[1:] {
 		if !server.KeyExists(ctx, key) {
 			continue
 		}
@@ -193,7 +193,7 @@ func handleSDIFFSTORE(ctx context.Context, cmd []string, server types.EchoVault,
 	}
 
 	var sets []*internal_set.Set
-	for _, key := range keys[2:] {
+	for _, key := range keys.ReadKeys[1:] {
 		set, ok := server.GetValue(ctx, key).(*internal_set.Set)
 		if !ok {
 			continue
@@ -228,7 +228,7 @@ func handleSDIFFSTORE(ctx context.Context, cmd []string, server types.EchoVault,
 	return []byte(res), nil
 }
 
-func handleSINTER(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleSINTER(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := sinterKeyFunc(cmd)
 	if err != nil {
 		return nil, err
@@ -243,7 +243,7 @@ func handleSINTER(ctx context.Context, cmd []string, server types.EchoVault, con
 		}
 	}()
 
-	for _, key := range keys[0:] {
+	for _, key := range keys.ReadKeys {
 		if !server.KeyExists(ctx, key) {
 			// If key does not exist, then there is no intersection
 			return []byte("*0\r\n"), nil
@@ -319,7 +319,7 @@ func handleSINTERCARD(ctx context.Context, cmd []string, server types.EchoVault,
 		}
 	}()
 
-	for _, key := range keys {
+	for _, key := range keys.ReadKeys {
 		if !server.KeyExists(ctx, key) {
 			// If key does not exist, then there is no intersection
 			return []byte(":0\r\n"), nil
@@ -350,7 +350,7 @@ func handleSINTERCARD(ctx context.Context, cmd []string, server types.EchoVault,
 	return []byte(fmt.Sprintf(":%d\r\n", intersect.Cardinality())), nil
 }
 
-func handleSINTERSTORE(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleSINTERSTORE(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := sinterstoreKeyFunc(cmd)
 	if err != nil {
 		return nil, err
@@ -365,7 +365,7 @@ func handleSINTERSTORE(ctx context.Context, cmd []string, server types.EchoVault
 		}
 	}()
 
-	for _, key := range keys[1:] {
+	for _, key := range keys.ReadKeys {
 		if !server.KeyExists(ctx, key) {
 			// If key does not exist, then there is no intersection
 			return []byte(":0\r\n"), nil
@@ -388,7 +388,7 @@ func handleSINTERSTORE(ctx context.Context, cmd []string, server types.EchoVault
 	}
 
 	intersect, _ := internal_set.Intersection(0, sets...)
-	destination := keys[0]
+	destination := keys.WriteKeys[0]
 
 	if server.KeyExists(ctx, destination) {
 		if _, err = server.KeyLock(ctx, destination); err != nil {
@@ -408,13 +408,13 @@ func handleSINTERSTORE(ctx context.Context, cmd []string, server types.EchoVault
 	return []byte(fmt.Sprintf(":%d\r\n", intersect.Cardinality())), nil
 }
 
-func handleSISMEMBER(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleSISMEMBER(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := sismemberKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	if !server.KeyExists(ctx, key) {
 		return []byte(":0\r\n"), nil
@@ -437,13 +437,13 @@ func handleSISMEMBER(ctx context.Context, cmd []string, server types.EchoVault,
 	return []byte(":1\r\n"), nil
 }
 
-func handleSMEMBERS(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleSMEMBERS(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := smembersKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	if !server.KeyExists(ctx, key) {
 		return []byte("*0\r\n"), nil
@@ -472,13 +472,13 @@ func handleSMEMBERS(ctx context.Context, cmd []string, server types.EchoVault, c
 	return []byte(res), nil
 }
 
-func handleSMISMEMBER(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleSMISMEMBER(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := smismemberKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 	members := cmd[2:]
 
 	if !server.KeyExists(ctx, key) {
@@ -515,14 +515,13 @@ func handleSMISMEMBER(ctx context.Context, cmd []string, server types.EchoVault,
 	return []byte(res), nil
 }
 
-func handleSMOVE(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleSMOVE(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := smoveKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	source := keys[0]
+	source, destination := keys.WriteKeys[0], keys.WriteKeys[1]
-	destination := keys[1]
 	member := cmd[3]
 
 	if !server.KeyExists(ctx, source) {
@@ -569,13 +568,13 @@ func handleSMOVE(ctx context.Context, cmd []string, server types.EchoVault, conn
 	return []byte(fmt.Sprintf(":%d\r\n", res)), nil
 }
 
-func handleSPOP(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleSPOP(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := spopKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 	count := 1
 
 	if len(cmd) == 3 {
@@ -613,13 +612,13 @@ func handleSPOP(ctx context.Context, cmd []string, server types.EchoVault, conn
 	return []byte(res), nil
 }
 
-func handleSRANDMEMBER(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleSRANDMEMBER(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := srandmemberKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 	count := 1
 
 	if len(cmd) == 3 {
@@ -657,13 +656,13 @@ func handleSRANDMEMBER(ctx context.Context, cmd []string, server types.EchoVault
 	return []byte(res), nil
 }
 
-func handleSREM(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleSREM(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := sremKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 	members := cmd[2:]
 
 	if !server.KeyExists(ctx, key) {
@@ -685,7 +684,7 @@ func handleSREM(ctx context.Context, cmd []string, server types.EchoVault, conn
 	return []byte(fmt.Sprintf(":%d\r\n", count)), nil
 }
 
-func handleSUNION(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleSUNION(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := sunionKeyFunc(cmd)
 	if err != nil {
 		return nil, err
@@ -700,7 +699,7 @@ func handleSUNION(ctx context.Context, cmd []string, server types.EchoVault, con
 		}
 	}()
 
-	for _, key := range keys {
+	for _, key := range keys.ReadKeys {
 		if !server.KeyExists(ctx, key) {
 			continue
 		}
@@ -736,7 +735,7 @@ func handleSUNION(ctx context.Context, cmd []string, server types.EchoVault, con
 	return []byte(res), nil
 }
 
-func handleSUNIONSTORE(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleSUNIONSTORE(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := sunionstoreKeyFunc(cmd)
 	if err != nil {
 		return nil, err
@@ -751,7 +750,7 @@ func handleSUNIONSTORE(ctx context.Context, cmd []string, server types.EchoVault
 		}
 	}()
 
-	for _, key := range keys[1:] {
+	for _, key := range keys.ReadKeys {
 		if !server.KeyExists(ctx, key) {
 			continue
 		}
@@ -776,7 +775,7 @@ func handleSUNIONSTORE(ctx context.Context, cmd []string, server types.EchoVault
 
 	union := internal_set.Union(sets...)
 
-	destination := cmd[1]
+	destination := keys.WriteKeys[0]
 
 	if server.KeyExists(ctx, destination) {
 		if _, err = server.KeyLock(ctx, destination); err != nil {

pkg/modules/set/key_funcs.go

@@ -17,48 +17,69 @@ package set
 import (
 	"errors"
 	"github.com/echovault/echovault/pkg/constants"
+	"github.com/echovault/echovault/pkg/types"
 	"slices"
 	"strings"
 )
 
-func saddKeyFunc(cmd []string) ([]string, error) {
+func saddKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func scardKeyFunc(cmd []string) ([]string, error) {
+func scardKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func sdiffKeyFunc(cmd []string) ([]string, error) {
+func sdiffKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func sdiffstoreKeyFunc(cmd []string) ([]string, error) {
+func sdiffstoreKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[2:],
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func sinterKeyFunc(cmd []string) ([]string, error) {
+func sinterKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func sintercardKeyFunc(cmd []string) ([]string, error) {
+func sintercardKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
 
 	limitIdx := slices.IndexFunc(cmd, func(s string) bool {
@@ -66,78 +87,126 @@ func sintercardKeyFunc(cmd []string) ([]string, error) {
 	})
 
 	if limitIdx == -1 {
-		return cmd[1:], nil
+		return types.AccessKeys{
+			Channels:  make([]string, 0),
+			ReadKeys:  cmd[1:],
+			WriteKeys: make([]string, 0),
+		}, nil
 	}
 
-	return cmd[1:limitIdx], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:limitIdx],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func sinterstoreKeyFunc(cmd []string) ([]string, error) {
+func sinterstoreKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[2:],
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func sismemberKeyFunc(cmd []string) ([]string, error) {
+func sismemberKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func smembersKeyFunc(cmd []string) ([]string, error) {
+func smembersKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func smismemberKeyFunc(cmd []string) ([]string, error) {
+func smismemberKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func smoveKeyFunc(cmd []string) ([]string, error) {
+func smoveKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:3], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:3],
+	}, nil
 }
 
-func spopKeyFunc(cmd []string) ([]string, error) {
+func spopKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 2 || len(cmd) > 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func srandmemberKeyFunc(cmd []string) ([]string, error) {
+func srandmemberKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 2 || len(cmd) > 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func sremKeyFunc(cmd []string) ([]string, error) {
+func sremKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func sunionKeyFunc(cmd []string) ([]string, error) {
+func sunionKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func sunionstoreKeyFunc(cmd []string) ([]string, error) {
+func sunionstoreKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[2:],
+		WriteKeys: cmd[1:2],
+	}, nil
 }

pkg/modules/sorted_set/commands.go

@@ -36,7 +36,7 @@ func handleZADD(ctx context.Context, cmd []string, server types.EchoVault, _ *ne
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 
 	var updatePolicy interface{} = nil
 	var comparison interface{} = nil
@@ -181,12 +181,12 @@ func handleZADD(ctx context.Context, cmd []string, server types.EchoVault, _ *ne
 	return []byte(fmt.Sprintf(":%d\r\n", set.Cardinality())), nil
 }
 
-func handleZCARD(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleZCARD(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := zcardKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	if !server.KeyExists(ctx, key) {
 		return []byte(":0\r\n"), nil
@@ -205,13 +205,13 @@ func handleZCARD(ctx context.Context, cmd []string, server types.EchoVault, conn
 	return []byte(fmt.Sprintf(":%d\r\n", set.Cardinality())), nil
 }
 
-func handleZCOUNT(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleZCOUNT(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := zcountKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	minimum := sorted_set.Score(math.Inf(-1))
 	switch internal.AdaptType(cmd[2]).(type) {
@@ -279,7 +279,7 @@ func handleZLEXCOUNT(ctx context.Context, cmd []string, server types.EchoVault,
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 	minimum := cmd[2]
 	maximum := cmd[3]
 
@@ -318,7 +318,7 @@ func handleZLEXCOUNT(ctx context.Context, cmd []string, server types.EchoVault,
 	return []byte(fmt.Sprintf(":%d\r\n", count)), nil
 }
 
-func handleZDIFF(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleZDIFF(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := zdiffKeyFunc(cmd)
 	if err != nil {
 		return nil, err
@@ -341,34 +341,34 @@ func handleZDIFF(ctx context.Context, cmd []string, server types.EchoVault, conn
 	}()
 
 	// Extract base set
-	if !server.KeyExists(ctx, keys[0]) {
+	if !server.KeyExists(ctx, keys.ReadKeys[0]) {
 		// If base set does not exist, return an empty array
 		return []byte("*0\r\n"), nil
 	}
-	if _, err = server.KeyRLock(ctx, keys[0]); err != nil {
+	if _, err = server.KeyRLock(ctx, keys.ReadKeys[0]); err != nil {
 		return nil, err
 	}
-	defer server.KeyRUnlock(ctx, keys[0])
+	defer server.KeyRUnlock(ctx, keys.ReadKeys[0])
-	baseSortedSet, ok := server.GetValue(ctx, keys[0]).(*sorted_set.SortedSet)
+	baseSortedSet, ok := server.GetValue(ctx, keys.ReadKeys[0]).(*sorted_set.SortedSet)
 	if !ok {
-		return nil, fmt.Errorf("value at %s is not a sorted set", keys[0])
+		return nil, fmt.Errorf("value at %s is not a sorted set", keys.ReadKeys[0])
 	}
 
 	// Extract the remaining sets
 	var sets []*sorted_set.SortedSet
 
-	for i := 1; i < len(keys); i++ {
+	for i := 1; i < len(keys.ReadKeys); i++ {
-		if !server.KeyExists(ctx, keys[i]) {
+		if !server.KeyExists(ctx, keys.ReadKeys[i]) {
 			continue
 		}
-		locked, err := server.KeyRLock(ctx, keys[i])
+		locked, err := server.KeyRLock(ctx, keys.ReadKeys[i])
 		if err != nil {
 			return nil, err
 		}
-		locks[keys[i]] = locked
+		locks[keys.ReadKeys[i]] = locked
-		set, ok := server.GetValue(ctx, keys[i]).(*sorted_set.SortedSet)
+		set, ok := server.GetValue(ctx, keys.ReadKeys[i]).(*sorted_set.SortedSet)
 		if !ok {
-			return nil, fmt.Errorf("value at %s is not a sorted set", keys[i])
+			return nil, fmt.Errorf("value at %s is not a sorted set", keys.ReadKeys[i])
 		}
 		sets = append(sets, set)
 	}
@@ -391,13 +391,13 @@ func handleZDIFF(ctx context.Context, cmd []string, server types.EchoVault, conn
 	return []byte(res), nil
 }
 
-func handleZDIFFSTORE(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleZDIFFSTORE(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := zdiffstoreKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	destination := cmd[1]
+	destination := keys.WriteKeys[0]
 
 	locks := make(map[string]bool)
 	defer func() {
@@ -409,29 +409,29 @@ func handleZDIFFSTORE(ctx context.Context, cmd []string, server types.EchoVault,
 	}()
 
 	// Extract base set
-	if !server.KeyExists(ctx, keys[0]) {
+	if !server.KeyExists(ctx, keys.ReadKeys[0]) {
 		// If base set does not exist, return 0
 		return []byte(":0\r\n"), nil
 	}
-	if _, err = server.KeyRLock(ctx, keys[0]); err != nil {
+	if _, err = server.KeyRLock(ctx, keys.ReadKeys[0]); err != nil {
 		return nil, err
 	}
-	defer server.KeyRUnlock(ctx, keys[0])
+	defer server.KeyRUnlock(ctx, keys.ReadKeys[0])
-	baseSortedSet, ok := server.GetValue(ctx, keys[0]).(*sorted_set.SortedSet)
+	baseSortedSet, ok := server.GetValue(ctx, keys.ReadKeys[0]).(*sorted_set.SortedSet)
 	if !ok {
-		return nil, fmt.Errorf("value at %s is not a sorted set", keys[0])
+		return nil, fmt.Errorf("value at %s is not a sorted set", keys.ReadKeys[0])
 	}
 
 	var sets []*sorted_set.SortedSet
 
-	for i := 1; i < len(keys); i++ {
+	for i := 1; i < len(keys.ReadKeys); i++ {
-		if server.KeyExists(ctx, keys[i]) {
+		if server.KeyExists(ctx, keys.ReadKeys[i]) {
-			if _, err = server.KeyRLock(ctx, keys[i]); err != nil {
+			if _, err = server.KeyRLock(ctx, keys.ReadKeys[i]); err != nil {
 				return nil, err
 			}
-			set, ok := server.GetValue(ctx, keys[i]).(*sorted_set.SortedSet)
+			set, ok := server.GetValue(ctx, keys.ReadKeys[i]).(*sorted_set.SortedSet)
 			if !ok {
-				return nil, fmt.Errorf("value at %s is not a sorted set", keys[i])
+				return nil, fmt.Errorf("value at %s is not a sorted set", keys.ReadKeys[i])
 			}
 			sets = append(sets, set)
 		}
@@ -457,13 +457,13 @@ func handleZDIFFSTORE(ctx context.Context, cmd []string, server types.EchoVault,
 	return []byte(fmt.Sprintf(":%d\r\n", diff.Cardinality())), nil
 }
 
-func handleZINCRBY(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleZINCRBY(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := zincrbyKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 	member := sorted_set.Value(cmd[3])
 	var increment sorted_set.Score
 
@@ -524,8 +524,8 @@ func handleZINCRBY(ctx context.Context, cmd []string, server types.EchoVault, co
 		strconv.FormatFloat(float64(set.Get(member).Score), 'f', -1, 64))), nil
 }
 
-func handleZINTER(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleZINTER(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
-	keys, err := zinterKeyFunc(cmd)
+	_, err := zinterKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
@@ -584,13 +584,13 @@ func handleZINTER(ctx context.Context, cmd []string, server types.EchoVault, con
 	return []byte(res), nil
 }
 
-func handleZINTERSTORE(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleZINTERSTORE(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
-	keys, err := zinterstoreKeyFunc(cmd)
+	k, err := zinterstoreKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	destination := keys[0]
+	destination := k.WriteKeys[0]
 
 	// Remove the destination keys from the command before parsing it
 	cmd = slices.DeleteFunc(cmd, func(s string) bool {
@@ -651,7 +651,7 @@ func handleZINTERSTORE(ctx context.Context, cmd []string, server types.EchoVault
 	return []byte(fmt.Sprintf(":%d\r\n", intersect.Cardinality())), nil
 }
 
-func handleZMPOP(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleZMPOP(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := zmpopKeyFunc(cmd)
 	if err != nil {
 		return nil, err
@@ -697,22 +697,22 @@ func handleZMPOP(ctx context.Context, cmd []string, server types.EchoVault, conn
 		}
 	}
 
-	for i := 0; i < len(keys); i++ {
+	for i := 0; i < len(keys.WriteKeys); i++ {
-		if server.KeyExists(ctx, keys[i]) {
+		if server.KeyExists(ctx, keys.WriteKeys[i]) {
-			if _, err = server.KeyLock(ctx, keys[i]); err != nil {
+			if _, err = server.KeyLock(ctx, keys.WriteKeys[i]); err != nil {
 				continue
 			}
-			v, ok := server.GetValue(ctx, keys[i]).(*sorted_set.SortedSet)
+			v, ok := server.GetValue(ctx, keys.WriteKeys[i]).(*sorted_set.SortedSet)
 			if !ok || v.Cardinality() == 0 {
-				server.KeyUnlock(ctx, keys[i])
+				server.KeyUnlock(ctx, keys.WriteKeys[i])
 				continue
 			}
 			popped, err := v.Pop(count, policy)
 			if err != nil {
-				server.KeyUnlock(ctx, keys[i])
+				server.KeyUnlock(ctx, keys.WriteKeys[i])
 				return nil, err
 			}
-			server.KeyUnlock(ctx, keys[i])
+			server.KeyUnlock(ctx, keys.WriteKeys[i])
 
 			res := fmt.Sprintf("*%d", popped.Cardinality())
 
@@ -729,13 +729,13 @@ func handleZMPOP(ctx context.Context, cmd []string, server types.EchoVault, conn
 	return []byte("*0\r\n"), nil
 }
 
-func handleZPOP(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleZPOP(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := zpopKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 	count := 1
 	policy := "min"
 
@@ -782,13 +782,13 @@ func handleZPOP(ctx context.Context, cmd []string, server types.EchoVault, conn
 	return []byte(res), nil
 }
 
-func handleZMSCORE(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleZMSCORE(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := zmscoreKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	if !server.KeyExists(ctx, key) {
 		return []byte("*0\r\n"), nil
@@ -824,13 +824,13 @@ func handleZMSCORE(ctx context.Context, cmd []string, server types.EchoVault, co
 	return []byte(res), nil
 }
 
-func handleZRANDMEMBER(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleZRANDMEMBER(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := zrandmemberKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	count := 1
 	if len(cmd) >= 3 {
@@ -888,7 +888,7 @@ func handleZRANK(ctx context.Context, cmd []string, server types.EchoVault, _ *n
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 	member := cmd[2]
 	withscores := false
 
@@ -938,7 +938,7 @@ func handleZREM(ctx context.Context, cmd []string, server types.EchoVault, _ *ne
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 
 	if !server.KeyExists(ctx, key) {
 		return []byte(":0\r\n"), nil
@@ -964,13 +964,13 @@ func handleZREM(ctx context.Context, cmd []string, server types.EchoVault, _ *ne
 	return []byte(fmt.Sprintf(":%d\r\n", deletedCount)), nil
 }
 
-func handleZSCORE(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleZSCORE(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := zscoreKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	if !server.KeyExists(ctx, key) {
 		return []byte("$-1\r\n"), nil
@@ -993,13 +993,13 @@ func handleZSCORE(ctx context.Context, cmd []string, server types.EchoVault, con
 	return []byte(fmt.Sprintf("$%d\r\n%s\r\n", len(score), score)), nil
 }
 
-func handleZREMRANGEBYSCORE(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleZREMRANGEBYSCORE(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := zremrangebyscoreKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 
 	deletedCount := 0
 
@@ -1037,13 +1037,13 @@ func handleZREMRANGEBYSCORE(ctx context.Context, cmd []string, server types.Echo
 	return []byte(fmt.Sprintf(":%d\r\n", deletedCount)), nil
 }
 
-func handleZREMRANGEBYRANK(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleZREMRANGEBYRANK(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := zremrangebyrankKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 
 	start, err := strconv.Atoi(cmd[2])
 	if err != nil {
@@ -1102,13 +1102,13 @@ func handleZREMRANGEBYRANK(ctx context.Context, cmd []string, server types.EchoV
 	return []byte(fmt.Sprintf(":%d\r\n", deletedCount)), nil
 }
 
-func handleZREMRANGEBYLEX(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleZREMRANGEBYLEX(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := zremrangebylexKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 	minimum := cmd[2]
 	maximum := cmd[3]
 
@@ -1149,13 +1149,13 @@ func handleZREMRANGEBYLEX(ctx context.Context, cmd []string, server types.EchoVa
 	return []byte(fmt.Sprintf(":%d\r\n", deletedCount)), nil
 }
 
-func handleZRANGE(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleZRANGE(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := zrangeKeyCount(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 	policy := "byscore"
 	scoreStart := math.Inf(-1) // Lower bound if policy is "byscore"
 	scoreStop := math.Inf(1)   // Upper bound if policy is "byscore"
@@ -1289,14 +1289,14 @@ func handleZRANGE(ctx context.Context, cmd []string, server types.EchoVault, con
 	return []byte(res), nil
 }
 
-func handleZRANGESTORE(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleZRANGESTORE(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := zrangeStoreKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	destination := keys[0]
+	destination := keys.WriteKeys[0]
-	source := keys[1]
+	source := keys.ReadKeys[0]
 	policy := "byscore"
 	scoreStart := math.Inf(-1) // Lower bound if policy is "byscore"
 	scoreStop := math.Inf(1)   // Upper bound if policy is "byfloat"
@@ -1431,7 +1431,7 @@ func handleZRANGESTORE(ctx context.Context, cmd []string, server types.EchoVault
 	return []byte(fmt.Sprintf(":%d\r\n", newSortedSet.Cardinality())), nil
 }
 
-func handleZUNION(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleZUNION(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	if _, err := zunionKeyFunc(cmd); err != nil {
 		return nil, err
 	}
@@ -1486,12 +1486,12 @@ func handleZUNION(ctx context.Context, cmd []string, server types.EchoVault, con
 }
 
 func handleZUNIONSTORE(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
-	keys, err := zunionstoreKeyFunc(cmd)
+	k, err := zunionstoreKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	destination := keys[0]
+	destination := k.WriteKeys[0]
 
 	// Remove destination key from list of keys
 	cmd = slices.DeleteFunc(cmd, func(s string) bool {

pkg/modules/sorted_set/key_funcs.go

@@ -17,34 +17,47 @@ package sorted_set
 import (
 	"errors"
 	"github.com/echovault/echovault/pkg/constants"
+	"github.com/echovault/echovault/pkg/types"
 	"slices"
 	"strings"
 )
 
-func zaddKeyFunc(cmd []string) ([]string, error) {
+func zaddKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func zcardKeyFunc(cmd []string) ([]string, error) {
+func zcardKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func zcountKeyFunc(cmd []string) ([]string, error) {
+func zcountKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func zdiffKeyFunc(cmd []string) ([]string, error) {
+func zdiffKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
 
 	withscoresIndex := slices.IndexFunc(cmd, func(s string) bool {
@@ -52,29 +65,45 @@ func zdiffKeyFunc(cmd []string) ([]string, error) {
 	})
 
 	if withscoresIndex == -1 {
-		return cmd[1:], nil
+		return types.AccessKeys{
+			Channels:  make([]string, 0),
+			ReadKeys:  cmd[1:],
+			WriteKeys: make([]string, 0),
+		}, nil
 	}
 
-	return cmd[1:withscoresIndex], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:withscoresIndex],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func zdiffstoreKeyFunc(cmd []string) ([]string, error) {
+func zdiffstoreKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[2:], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[2:],
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func zincrbyKeyFunc(cmd []string) ([]string, error) {
+func zincrbyKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func zinterKeyFunc(cmd []string) ([]string, error) {
+func zinterKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
 	endIdx := slices.IndexFunc(cmd[1:], func(s string) bool {
 		if strings.EqualFold(s, "WEIGHTS") ||
@@ -85,17 +114,25 @@ func zinterKeyFunc(cmd []string) ([]string, error) {
 		return false
 	})
 	if endIdx == -1 {
-		return cmd[1:], nil
+		return types.AccessKeys{
+			Channels:  make([]string, 0),
+			ReadKeys:  cmd[1:],
+			WriteKeys: make([]string, 0),
+		}, nil
 	}
 	if endIdx >= 1 {
-		return cmd[1:endIdx], nil
+		return types.AccessKeys{
+			Channels:  make([]string, 0),
+			ReadKeys:  cmd[1:endIdx],
+			WriteKeys: make([]string, 0),
+		}, nil
 	}
-	return nil, errors.New(constants.WrongArgsResponse)
+	return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 }
 
-func zinterstoreKeyFunc(cmd []string) ([]string, error) {
+func zinterstoreKeyFunc(cmd []string) (types.AccessKeys, error) {
-	if len(cmd) < 2 {
+	if len(cmd) < 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
 	endIdx := slices.IndexFunc(cmd[1:], func(s string) bool {
 		if strings.EqualFold(s, "WEIGHTS") ||
@@ -106,124 +143,192 @@ func zinterstoreKeyFunc(cmd []string) ([]string, error) {
 		return false
 	})
 	if endIdx == -1 {
-		return cmd[1:], nil
+		return types.AccessKeys{
+			Channels:  make([]string, 0),
+			ReadKeys:  cmd[2:],
+			WriteKeys: cmd[1:2],
+		}, nil
 	}
-	if endIdx >= 2 {
+	if endIdx >= 3 {
-		return cmd[1:endIdx], nil
+		return types.AccessKeys{
+			Channels:  make([]string, 0),
+			ReadKeys:  cmd[2:endIdx],
+			WriteKeys: cmd[1:2],
+		}, nil
 	}
-	return nil, errors.New(constants.WrongArgsResponse)
+	return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 }
 
-func zmpopKeyFunc(cmd []string) ([]string, error) {
+func zmpopKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
 	endIdx := slices.IndexFunc(cmd, func(s string) bool {
 		return slices.Contains([]string{"MIN", "MAX", "COUNT"}, strings.ToUpper(s))
 	})
 	if endIdx == -1 {
-		return cmd[1:], nil
+		return types.AccessKeys{
+			Channels:  make([]string, 0),
+			ReadKeys:  make([]string, 0),
+			WriteKeys: cmd[1:],
+		}, nil
 	}
 	if endIdx >= 2 {
-		return cmd[1:endIdx], nil
+		return types.AccessKeys{
+			Channels:  make([]string, 0),
+			ReadKeys:  make([]string, 0),
+			WriteKeys: cmd[1:endIdx],
+		}, nil
 	}
-	return nil, errors.New(constants.WrongArgsResponse)
+	return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 }
 
-func zmscoreKeyFunc(cmd []string) ([]string, error) {
+func zmscoreKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func zpopKeyFunc(cmd []string) ([]string, error) {
+func zpopKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 2 || len(cmd) > 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func zrandmemberKeyFunc(cmd []string) ([]string, error) {
+func zrandmemberKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 2 || len(cmd) > 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func zrankKeyFunc(cmd []string) ([]string, error) {
+func zrankKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 || len(cmd) > 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func zremKeyFunc(cmd []string) ([]string, error) {
+func zremKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func zrevrankKeyFunc(cmd []string) ([]string, error) {
+func zrevrankKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func zscoreKeyFunc(cmd []string) ([]string, error) {
+func zscoreKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func zremrangebylexKeyFunc(cmd []string) ([]string, error) {
+func zremrangebylexKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func zremrangebyrankKeyFunc(cmd []string) ([]string, error) {
+func zremrangebyrankKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func zremrangebyscoreKeyFunc(cmd []string) ([]string, error) {
+func zremrangebyscoreKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func zlexcountKeyFunc(cmd []string) ([]string, error) {
+func zlexcountKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func zrangeKeyCount(cmd []string) ([]string, error) {
+func zrangeKeyCount(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 4 || len(cmd) > 10 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:2], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func zrangeStoreKeyFunc(cmd []string) ([]string, error) {
+func zrangeStoreKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 5 || len(cmd) > 11 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return cmd[1:3], nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[2:3],
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func zunionKeyFunc(cmd []string) ([]string, error) {
+func zunionKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) < 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
 	endIdx := slices.IndexFunc(cmd[1:], func(s string) bool {
 		if strings.EqualFold(s, "WEIGHTS") ||
@@ -234,17 +339,25 @@ func zunionKeyFunc(cmd []string) ([]string, error) {
 		return false
 	})
 	if endIdx == -1 {
-		return cmd[1:], nil
+		return types.AccessKeys{
+			Channels:  make([]string, 0),
+			ReadKeys:  cmd[1:],
+			WriteKeys: make([]string, 0),
+		}, nil
 	}
 	if endIdx >= 1 {
-		return cmd[1:endIdx], nil
+		return types.AccessKeys{
+			Channels:  make([]string, 0),
+			ReadKeys:  cmd[1:endIdx],
+			WriteKeys: cmd[1:endIdx],
+		}, nil
 	}
-	return nil, errors.New(constants.WrongArgsResponse)
+	return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 }
 
-func zunionstoreKeyFunc(cmd []string) ([]string, error) {
+func zunionstoreKeyFunc(cmd []string) (types.AccessKeys, error) {
-	if len(cmd) < 2 {
+	if len(cmd) < 3 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
 	endIdx := slices.IndexFunc(cmd[1:], func(s string) bool {
 		if strings.EqualFold(s, "WEIGHTS") ||
@@ -255,10 +368,18 @@ func zunionstoreKeyFunc(cmd []string) ([]string, error) {
 		return false
 	})
 	if endIdx == -1 {
-		return cmd[1:], nil
+		return types.AccessKeys{
+			Channels:  make([]string, 0),
+			ReadKeys:  cmd[2:],
+			WriteKeys: cmd[1:2],
+		}, nil
 	}
 	if endIdx >= 1 {
-		return cmd[1:endIdx], nil
+		return types.AccessKeys{
+			Channels:  make([]string, 0),
+			ReadKeys:  cmd[2:endIdx],
+			WriteKeys: cmd[1:2],
+		}, nil
 	}
-	return nil, errors.New(constants.WrongArgsResponse)
+	return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 }

pkg/modules/string/commands.go

@@ -24,13 +24,13 @@ import (
 	"net"
 )
 
-func handleSetRange(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleSetRange(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := setRangeKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.WriteKeys[0]
 
 	offset, ok := internal.AdaptType(cmd[2]).(int)
 	if !ok {
@@ -105,7 +105,7 @@ func handleStrLen(ctx context.Context, cmd []string, server types.EchoVault, con
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	if !server.KeyExists(ctx, key) {
 		return []byte(":0\r\n"), nil
@@ -125,13 +125,13 @@ func handleStrLen(ctx context.Context, cmd []string, server types.EchoVault, con
 	return []byte(fmt.Sprintf(":%d\r\n", len(value))), nil
 }
 
-func handleSubStr(ctx context.Context, cmd []string, server types.EchoVault, conn *net.Conn) ([]byte, error) {
+func handleSubStr(ctx context.Context, cmd []string, server types.EchoVault, _ *net.Conn) ([]byte, error) {
 	keys, err := subStrKeyFunc(cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	key := keys[0]
+	key := keys.ReadKeys[0]
 
 	start, startOk := internal.AdaptType(cmd[2]).(int)
 	end, endOk := internal.AdaptType(cmd[3]).(int)

pkg/modules/string/key_funcs.go

@@ -17,25 +17,38 @@ package str
 import (
 	"errors"
 	"github.com/echovault/echovault/pkg/constants"
+	"github.com/echovault/echovault/pkg/types"
 )
 
-func setRangeKeyFunc(cmd []string) ([]string, error) {
+func setRangeKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  make([]string, 0),
+		WriteKeys: cmd[1:2],
+	}, nil
 }
 
-func strLenKeyFunc(cmd []string) ([]string, error) {
+func strLenKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 2 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }
 
-func subStrKeyFunc(cmd []string) ([]string, error) {
+func subStrKeyFunc(cmd []string) (types.AccessKeys, error) {
 	if len(cmd) != 4 {
-		return nil, errors.New(constants.WrongArgsResponse)
+		return types.AccessKeys{}, errors.New(constants.WrongArgsResponse)
 	}
-	return []string{cmd[1]}, nil
+	return types.AccessKeys{
+		Channels:  make([]string, 0),
+		ReadKeys:  cmd[1:2],
+		WriteKeys: make([]string, 0),
+	}, nil
 }