session存储
一個基于內存的session存儲接口的實現,其他的存儲方式,讀者可以自行參考示例來實現,內存的實現請看下面的例子代碼
package memoryimport ("container/list""github.com/astaxie/session""sync""time" )var pder = &Provider{list: list.New()}type SessionStore struct {sid string //session id唯一標示timeAccessed time.Time //最后訪問時間value map[interface{}]interface{} //session里面存儲的值 }func (st *SessionStore) Set(key, value interface{}) error {st.value[key] = valuepder.SessionUpdate(st.sid)return nil }func (st *SessionStore) Get(key interface{}) interface{} {pder.SessionUpdate(st.sid)if v, ok := st.value[key]; ok {return v} else {return nil}return nil }func (st *SessionStore) Delete(key interface{}) error {delete(st.value, key)pder.SessionUpdate(st.sid)return nil }func (st *SessionStore) SessionID() string {return st.sid }type Provider struct {lock sync.Mutex //用來鎖sessions map[string]*list.Element //用來存儲在內存list *list.List //用來做gc }func (pder *Provider) SessionInit(sid string) (session.Session, error) {pder.lock.Lock()defer pder.lock.Unlock()v := make(map[interface{}]interface{}, 0)newsess := &SessionStore{sid: sid, timeAccessed: time.Now(), value: v}element := pder.list.PushBack(newsess)pder.sessions[sid] = elementreturn newsess, nil }func (pder *Provider) SessionRead(sid string) (session.Session, error) {if element, ok := pder.sessions[sid]; ok {return element.Value.(*SessionStore), nil} else {sess, err := pder.SessionInit(sid)return sess, err}return nil, nil }func (pder *Provider) SessionDestroy(sid string) error {if element, ok := pder.sessions[sid]; ok {delete(pder.sessions, sid)pder.list.Remove(element)return nil}return nil }func (pder *Provider) SessionGC(maxlifetime int64) {pder.lock.Lock()defer pder.lock.Unlock()for {element := pder.list.Back()if element == nil {break}if (element.Value.(*SessionStore).timeAccessed.Unix() + maxlifetime) < time.Now().Unix() {pder.list.Remove(element)delete(pder.sessions, element.Value.(*SessionStore).sid)} else {break}} }func (pder *Provider) SessionUpdate(sid string) error {pder.lock.Lock()defer pder.lock.Unlock()if element, ok := pder.sessions[sid]; ok {element.Value.(*SessionStore).timeAccessed = time.Now()pder.list.MoveToFront(element)return nil}return nil }func init() {pder.sessions = make(map[string]*list.Element, 0)session.Register("memory", pder) }上面這個代碼實現了一個內存存儲的session機制。通過init函數注冊到session管理器中。這樣就可以方便的調用了。我們如何來調用該引擎呢?請看下面的代碼
import ("github.com/astaxie/session"_ "github.com/astaxie/session/providers/memory" )當import的時候已經執行了memory函數里面的init函數,這樣就已經注冊到session管理器中,我們就可以使用了,通過如下方式就可以初始化一個session管理器:
var globalSessions *session.Manager//然后在init函數中初始化 func init() {globalSessions, _ = session.NewManager("memory", "gosessionid", 3600)go globalSessions.GC() }總結
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