fix #1473,Only update redis session if it already exist

session/redis/sess_redis.go

@@ -98,15 +98,18 @@ func (rs *SessionStore) SessionID() string {
 
 // SessionRelease save session values to redis
 func (rs *SessionStore) SessionRelease(w http.ResponseWriter) {
-	c := rs.p.Get()
-	defer c.Close()
 
 	b, err := session.EncodeGob(rs.values)
 	if err != nil {
 		return
 	}
 
-	c.Do("SETEX", rs.sid, rs.maxlifetime, string(b))
+	c := rs.p.Get()
+	defer c.Close()
+	// Update session value if exists or error.
+	if existed, err := redis.Bool(c.Do("EXISTS", rs.sid)); existed || err != nil {
+		c.Do("SETEX", rs.sid, rs.maxlifetime, string(b))
+	}
 }
 
 // Provider redis session provider

session/redis/sess_redis_test.go

@@ -0,0 +1,64 @@
+// Copyright 2016 beego Author. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package redis
+
+import (
+	"testing"
+)
+
+func TestSessionRelease(t *testing.T) {
+
+	provider := Provider{}
+	if err := provider.SessionInit(3, "127.0.0.1:6379"); err != nil {
+		t.Fatal("init session err,", err)
+	}
+
+	sessionID := "beegosessionid_00001"
+
+	session, err := provider.SessionRegenerate("", sessionID)
+	if err != nil {
+		t.Fatal("new session error,", err)
+	}
+
+	// set item.
+	session.Set("k1", "v1")
+	// update.
+	session.SessionRelease(nil)
+
+	session, err = provider.SessionRead(sessionID)
+	if err != nil {
+		t.Fatal("read session error,", err)
+	}
+	if v1 := session.Get("k1"); v1 == nil {
+		t.Fatal("want v1 got nil")
+	} else if v, _ := v1.(string); v != "v1" {
+		t.Fatalf("want v1 got %s", v)
+	}
+
+	// delete
+	provider.SessionDestroy(sessionID)
+	session.Set("k2", "v2")
+
+	session.SessionRelease(nil)
+
+	session, err = provider.SessionRead(sessionID)
+	if err != nil {
+		t.Fatal("read session error,", err)
+	}
+	if session.Get("k1") != nil || session.Get("k2") != nil {
+		t.Fatalf("want emtpy session value,got %s,%s", session.Get("k1"), session.Get("k2"))
+	}
+
+}