123 lines
3.1 KiB
Markdown
123 lines
3.1 KiB
Markdown
#6.3 session存储
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上一节我们介绍了Session管理器的实现原理，定义了如何实现session存储的接口，这小节我们讲通过一个例子来实现内存的session存储，其他类似数据库或者文件的存储，用户可以根据相应的接口定义来实现，内存的实现请看下面的例子代码
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package memory
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import (
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"session/session"
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"time"
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)
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var d = &Provider{}
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type SessionStore struct {
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sid string //session id唯一标示
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timeAccessed time.Time //最后访问时间
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value map[interface{}]interface{} //session里面存储的值
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}
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func (this *SessionStore) Set(key, value interface{}) bool {
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this.value[key] = value
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d.SessionUpdate(this.sid)
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return true
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}
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func (this *SessionStore) Get(key interface{}) interface{} {
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d.SessionUpdate(this.sid)
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if v, ok := this.value[key]; ok {
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return v
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} else {
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return ""
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}
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}
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func (this *SessionStore) Del(key interface{}) bool {
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delete(this.value, key)
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d.SessionUpdate(this.sid)
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return true
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}
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type Provider struct {
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lock sync.Mutex //用来锁
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sessions map[string]*SessionStore //用来存储在内存
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list *list.List //用来做gc
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}
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func (this *Provider) SessionInit(sid string) (session.Session, error) {
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this.lock.Lock()
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defer this.lock.Unlock()
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v := make(map[interface{}]interface{}, 0)
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newsess := &SessionStore{"sid": sid, "timeAccessed": time.Now(), "value": v}
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this.sessions[sid] = newsess
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this.list.Push(newsess)
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return newsess
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}
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func (this *Provider) SessionRead(sid string) (session.Session, error) {
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if s, ok := this.sessions[sid]; ok {
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return s, nil
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} else {
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sess, err := this.SessionInit(sid)
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return sess, err
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}
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}
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func (this *Provider) SessionDestroy(sid string) bool {
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if s, ok := this.sessions[sid]; ok {
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delete(this.table, sid)
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this.list.Remove(s)
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return true
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} else {
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return false
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}
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}
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func (this *Provider) SessionGC(maxlifetime int64) {
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this.lock.Lock()
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defer this.lock.Unlock()
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for {
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element := this.list.Back()
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if element == nil {
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break
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}
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if (element.Value.(*SessionStore).timeAccessed.Unix() + maxlifetime) < time.Now().Unix() {
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this.list.Remove(element)
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delete(this.table, element.Value.(*SessionStore).sid)
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} else {
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break
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}
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}
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}
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func (this *Provider) SessionUpdate(sid string) bool {
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this.lock.Lock()
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defer this.lock.Unlock()
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if element, ok := this.sessions[sid]; ok {
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element.Value.(*SessionStore).value = s.value
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this.moveToFront(element)
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return true
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} else {
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return false
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}
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}
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func (this *Provider) moveToFront(element *list.Element) {
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this.lock.Lock()
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defer this.lock.Unlock()
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element.Value.(*SessionStore).timeAccessed = time.Now()
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this.list.MoveToFront(element)
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}
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func init() {
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session.Register("memory", d)
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}
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上面这个代码实现了一个内存存储实现的session机制
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## links
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* [目录](<preface.md>)
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* 上一节: [Go如何使用session](<6.2.md>)
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* 下一节: [预防session劫持](<6.4.md>)
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## LastModified
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* $Id$ |