From 3037996363b9dbd70757949df483bd063a9b94db Mon Sep 17 00:00:00 2001
From: ydf <4960943+ydf@users.noreply.github.com>
Date: Fri, 9 Aug 2024 10:54:37 +0800
Subject: [PATCH] command: select, flushall (#32)

The Redis WordPress plugin (wp-redis) uses SELECT to connect to a database.
Older versions of this plugin (<0.8.0) also use FLUSHALL instead of FLUSHDB
to flush the cache.

See https://github.com/pantheon-systems/wp-redis
---
 internal/command/command.go     |  4 ++++
 internal/command/conn/select.go | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 internal/command/conn/select.go

diff --git a/internal/command/command.go b/internal/command/command.go
index 15b0a1e..a164d12 100644
--- a/internal/command/command.go
+++ b/internal/command/command.go
@@ -28,6 +28,8 @@ func Parse(args [][]byte) (redis.Cmd, error) {
 		return server.ParseDBSize(b)
 	case "flushdb":
 		return key.ParseFlushDB(b)
+	case "flushall":
+		return key.ParseFlushDB(b)
 	case "info":
 		return server.ParseOK(b)
 	case "lolwut":
@@ -38,6 +40,8 @@ func Parse(args [][]byte) (redis.Cmd, error) {
 		return conn.ParseEcho(b)
 	case "ping":
 		return conn.ParsePing(b)
+	case "select":
+		return conn.ParseSelect(b)
 
 	// key
 	case "del":
diff --git a/internal/command/conn/select.go b/internal/command/conn/select.go
new file mode 100644
index 0000000..e222df2
--- /dev/null
+++ b/internal/command/conn/select.go
@@ -0,0 +1,33 @@
+package conn
+
+import (
+	"github.com/nalgeon/redka/internal/parser"
+	"github.com/nalgeon/redka/internal/redis"
+)
+
+const (
+	RESPONSE = "OK"
+)
+
+// Returns the server's liveliness response.
+// https://redis.io/commands/select
+type Select struct {
+	redis.BaseCmd
+	index int
+}
+
+func ParseSelect(b redis.BaseCmd) (Select, error) {
+	cmd := Select{BaseCmd: b}
+	err := parser.New(
+		parser.Int(&cmd.index),
+	).Required(1).Run(cmd.Args())
+	if err != nil {
+		return Select{}, err
+	}
+	return cmd, nil
+}
+
+func (c Select) Run(w redis.Writer, _ redis.Redka) (any, error) {
+	w.WriteBulkString(RESPONSE)
+	return RESPONSE, nil
+}