fix #248

@@ -116,6 +116,15 @@ func (fp *FileProvider) SessionRead(sid string) (SessionStore, error) {
 	return ss, nil
 	return ss, nil
 }
 }
 
 
+func (fp *FileProvider) SessionExist(sid string) bool {
+	_, err := os.Stat(path.Join(fp.savePath, string(sid[0]), string(sid[1]), sid))
+	if err == nil {
+		return true
+	} else {
+		return false
+	}
+}
+
 func (fp *FileProvider) SessionDestroy(sid string) error {
 func (fp *FileProvider) SessionDestroy(sid string) error {
 	os.Remove(path.Join(fp.savePath))
 	os.Remove(path.Join(fp.savePath))
 	return nil
 	return nil

@@ -87,6 +87,16 @@ func (pder *MemProvider) SessionRead(sid string) (SessionStore, error) {
 	return nil, nil
 	return nil, nil
 }
 }
 
 
+func (pder *MemProvider) SessionExist(sid string) bool {
+	pder.lock.RLock()
+	defer pder.lock.RUnlock()
+	if _, ok := pder.sessions[sid]; ok {
+		return true
+	} else {
+		return false
+	}
+}
+
 func (pder *MemProvider) SessionRegenerate(oldsid, sid string) (SessionStore, error) {
 func (pder *MemProvider) SessionRegenerate(oldsid, sid string) (SessionStore, error) {
 	pder.lock.RLock()
 	pder.lock.RLock()
 	if element, ok := pder.sessions[oldsid]; ok {
 	if element, ok := pder.sessions[oldsid]; ok {

@@ -110,6 +110,18 @@ func (mp *MysqlProvider) SessionRead(sid string) (SessionStore, error) {
 	return rs, nil
 	return rs, nil
 }
 }
 
 
+func (mp *MysqlProvider) SessionExist(sid string) bool {
+	c := mp.connectInit()
+	row := c.QueryRow("select session_data from session where session_key=?", sid)
+	var sessiondata []byte
+	err := row.Scan(&sessiondata)
+	if err == sql.ErrNoRows {
+		return false
+	} else {
+		return true
+	}
+}
+
 func (mp *MysqlProvider) SessionRegenerate(oldsid, sid string) (SessionStore, error) {
 func (mp *MysqlProvider) SessionRegenerate(oldsid, sid string) (SessionStore, error) {
 	c := mp.connectInit()
 	c := mp.connectInit()
 	row := c.QueryRow("select session_data from session where session_key=?", oldsid)
 	row := c.QueryRow("select session_data from session where session_key=?", oldsid)

@@ -145,6 +145,15 @@ func (rp *RedisProvider) SessionRead(sid string) (SessionStore, error) {
 	return rs, nil
 	return rs, nil
 }
 }
 
 
+func (rp *RedisProvider) SessionExist(sid string) bool {
+	c := rp.poollist.Get()
+	if str, err := redis.String(c.Do("HGET", sid, sid)); err != nil || str == "" {
+		return false
+	} else {
+		return true
+	}
+}
+
 func (rp *RedisProvider) SessionRegenerate(oldsid, sid string) (SessionStore, error) {
 func (rp *RedisProvider) SessionRegenerate(oldsid, sid string) (SessionStore, error) {
 	c := rp.poollist.Get()
 	c := rp.poollist.Get()
 	if str, err := redis.String(c.Do("HGET", oldsid, oldsid)); err != nil || str == "" {
 	if str, err := redis.String(c.Do("HGET", oldsid, oldsid)); err != nil || str == "" {

@@ -25,6 +25,7 @@ type SessionStore interface {
 type Provider interface {
 type Provider interface {
 	SessionInit(maxlifetime int64, savePath string) error
 	SessionInit(maxlifetime int64, savePath string) error
 	SessionRead(sid string) (SessionStore, error)
 	SessionRead(sid string) (SessionStore, error)
+	SessionExist(sid string) bool
 	SessionRegenerate(oldsid, sid string) (SessionStore, error)
 	SessionRegenerate(oldsid, sid string) (SessionStore, error)
 	SessionDestroy(sid string) error
 	SessionDestroy(sid string) error
 	SessionAll() int //get all active session
 	SessionAll() int //get all active session
@@ -133,7 +134,22 @@ func (manager *Manager) SessionStart(w http.ResponseWriter, r *http.Request) (se
 		r.AddCookie(cookie)
 		r.AddCookie(cookie)
 	} else {
 	} else {
 		sid, _ := url.QueryUnescape(cookie.Value)
 		sid, _ := url.QueryUnescape(cookie.Value)
+		if manager.provider.SessionExist(sid) {
 			session, _ = manager.provider.SessionRead(sid)
 			session, _ = manager.provider.SessionRead(sid)
+		} else {
+			sid = manager.sessionId(r)
+			session, _ = manager.provider.SessionRead(sid)
+			cookie = &http.Cookie{Name: manager.cookieName,
+				Value:    url.QueryEscape(sid),
+				Path:     "/",
+				HttpOnly: true,
+				Secure:   manager.secure}
+			if manager.maxage >= 0 {
+				cookie.MaxAge = manager.maxage
+			}
+			http.SetCookie(w, cookie)
+			r.AddCookie(cookie)
+		}
 	}
 	}
 	return
 	return
 }
 }