diff --git a/server/middleware/auth.go b/server/middleware/auth.go
index 632dd506..76ba00f7 100644
--- a/server/middleware/auth.go
+++ b/server/middleware/auth.go
@@ -7,11 +7,13 @@ import (
 	"os"
 	"path"
 	"strconv"
+	"strings"
 	"sync"
 	"time"
 
 	"github.com/Monkey-Mouse/mo2/mo2utils/mo2errors"
 	"github.com/Monkey-Mouse/mo2/server/controller/badresponse"
+	"github.com/Monkey-Mouse/mo2/server/middleware/pool"
 
 	"github.com/gin-gonic/gin"
 	"github.com/go-redis/redis"
@@ -31,6 +33,13 @@ var rdb *redis.Client
 var dicChan chan *concurrent.Map = make(chan *concurrent.Map)
 var lock = sync.Mutex{}
 var errAuth = errors.New("authentication failed")
+var strpool *pool.Pool = &pool.Pool{}
+
+func init() {
+	strpool.Init(func() interface{} {
+		return &strings.Builder{}
+	})
+}
 
 // H handlermap, like gin router
 var H = handlerMap{handlers, "", make([][]string, 0), -1}
@@ -104,11 +113,16 @@ func resetBlocker() {
 }
 
 func redisCheckRL(prop string, ip string, limit int) bool {
+	sb := strpool.Rent().(*strings.Builder)
+	sb.Reset()
+	sb.WriteString(prop)
+	sb.WriteString(ip)
+	defer strpool.Return(sb)
 	// rate limit logic
 	if limit < 0 {
 		return true
 	}
-	key := prop + ip
+	key := sb.String()
 	re, err := rdb.HIncrBy(redisHashSet, key, 1).Result()
 	if err != nil {
 		log.Fatal(err)
@@ -121,11 +135,16 @@ func redisCheckRL(prop string, ip string, limit int) bool {
 }
 
 func checkRL(prop string, ip string, limit int) bool {
+	sb := strpool.Rent().(*strings.Builder)
+	sb.Reset()
+	sb.WriteString(prop)
+	sb.WriteString(ip)
+	defer strpool.Return(sb)
 	// rate limit logic
 	if limit < 0 {
 		return true
 	}
-	key := prop + ip
+	key := sb.String()
 	dic := <-dicChan
 	lock.Lock()
 	v, ext := dic.Load(key)
@@ -247,7 +266,7 @@ func (h handlerMap) HandlerWithRL(
 	handler gin.HandlerFunc,
 	ratelimit int,
 	roles ...string) {
-	if roles != nil && len(roles) != 0 {
+	if len(roles) != 0 {
 		h.roles = append(h.roles, roles)
 	}
 	key := handlerKey{
diff --git a/server/middleware/pool/pool.go b/server/middleware/pool/pool.go
new file mode 100644
index 00000000..715397e2
--- /dev/null
+++ b/server/middleware/pool/pool.go
@@ -0,0 +1,37 @@
+package pool
+
+import (
+	"container/list"
+	"sync"
+)
+
+type Pool struct {
+	pool list.List
+	fac  ObjFactory
+}
+
+type ObjFactory func() interface{}
+
+var lock = sync.Mutex{}
+
+func (p *Pool) Rent() interface{} {
+	lock.Lock()
+	defer lock.Unlock()
+	if p.pool.Len() == 0 {
+		return p.fac()
+	}
+	return p.pool.Remove(p.pool.Back())
+}
+func (p *Pool) Len() int {
+	return p.pool.Len()
+}
+
+func (p *Pool) Return(e interface{}) {
+	lock.Lock()
+	defer lock.Unlock()
+	p.pool.PushBack(e)
+}
+func (p *Pool) Init(fac ObjFactory) {
+	p.pool.Init()
+	p.fac = fac
+}