C# DataGridView的一些使用方法
阿新 • • 發佈：2020-12-24
技術標籤：GO
在文章beego Session redis儲存以及是否阻塞我們說到session 是無阻塞的，session的介面對使用者來說是一個字典（C# diction， Go是map）， 儲存所有的ssion也是一個字典（類似於C#Dictionary<string【sessionid 用於區分使用者】,Dictionary<string【使用者設定的key】,object>>）
首先我們來看看redis session （ledis_session.go）的原始碼吧，和C#相同， 有一個SessionStore負責儲存和Provider；
package redis import ( "net/http" "strconv" "strings" "sync" "time" "github.com/astaxie/beego/session" "github.com/gomodule/redigo/redis" ) var redispder = &Provider{} // MaxPoolSize redis max pool size var MaxPoolSize = 100 // SessionStore redis session store type SessionStore struct { p *redis.Pool sid string lock sync.RWMutex values map[interface{}]interface{} maxlifetime int64 } // Set value in redis session func (rs *SessionStore) Set(key, value interface{}) error { rs.lock.Lock() defer rs.lock.Unlock() rs.values[key] = value return nil } // Get value in redis session func (rs *SessionStore) Get(key interface{}) interface{} { rs.lock.RLock() defer rs.lock.RUnlock() if v, ok := rs.values[key]; ok { return v } return nil } // Delete value in redis session func (rs *SessionStore) Delete(key interface{}) error { rs.lock.Lock() defer rs.lock.Unlock() delete(rs.values, key) return nil } // Flush clear all values in redis session func (rs *SessionStore) Flush() error { rs.lock.Lock() defer rs.lock.Unlock() rs.values = make(map[interface{}]interface{}) return nil } // SessionID get redis session id func (rs *SessionStore) SessionID() string { return rs.sid } // SessionRelease save session values to redis func (rs *SessionStore) SessionRelease(w http.ResponseWriter) { b, err := session.EncodeGob(rs.values) if err != nil { return } c := rs.p.Get() defer c.Close() c.Do("SETEX", rs.sid, rs.maxlifetime, string(b)) } // Provider redis session provider type Provider struct { maxlifetime int64 savePath string poolsize int password string dbNum int poollist *redis.Pool } // SessionInit init redis session // savepath like redis server addr,pool size,password,dbnum,IdleTimeout second // e.g. 127.0.0.1:6379,100,astaxie,0,30 func (rp *Provider) SessionInit(maxlifetime int64, savePath string) error { rp.maxlifetime = maxlifetime configs := strings.Split(savePath, ",") if len(configs) > 0 { rp.savePath = configs[0] } if len(configs) > 1 { poolsize, err := strconv.Atoi(configs[1]) if err != nil || poolsize < 0 { rp.poolsize = MaxPoolSize } else { rp.poolsize = poolsize } } else { rp.poolsize = MaxPoolSize } if len(configs) > 2 { rp.password = configs[2] } if len(configs) > 3 { dbnum, err := strconv.Atoi(configs[3]) if err != nil || dbnum < 0 { rp.dbNum = 0 } else { rp.dbNum = dbnum } } else { rp.dbNum = 0 } var idleTimeout time.Duration = 0 if len(configs) > 4 { timeout, err := strconv.Atoi(configs[4]) if err == nil && timeout > 0 { idleTimeout = time.Duration(timeout) * time.Second } } rp.poollist = &redis.Pool{ Dial: func() (redis.Conn, error) { c, err := redis.Dial("tcp", rp.savePath) if err != nil { return nil, err } if rp.password != "" { if _, err = c.Do("AUTH", rp.password); err != nil { c.Close() return nil, err } } // some redis proxy such as twemproxy is not support select command if rp.dbNum > 0 { _, err = c.Do("SELECT", rp.dbNum) if err != nil { c.Close() return nil, err } } return c, err }, MaxIdle: rp.poolsize, } rp.poollist.IdleTimeout = idleTimeout return rp.poollist.Get().Err() } // SessionRead read redis session by sid func (rp *Provider) SessionRead(sid string) (session.Store, error) { c := rp.poollist.Get() defer c.Close() var kv map[interface{}]interface{} kvs, err := redis.String(c.Do("GET", sid)) if err != nil && err != redis.ErrNil { return nil, err } if len(kvs) == 0 { kv = make(map[interface{}]interface{}) } else { if kv, err = session.DecodeGob([]byte(kvs)); err != nil { return nil, err } } rs := &SessionStore{p: rp.poollist, sid: sid, values: kv, maxlifetime: rp.maxlifetime} return rs, nil } // SessionExist check redis session exist by sid func (rp *Provider) SessionExist(sid string) bool { c := rp.poollist.Get() defer c.Close() if existed, err := redis.Int(c.Do("EXISTS", sid)); err != nil || existed == 0 { return false } return true } // SessionRegenerate generate new sid for redis session func (rp *Provider) SessionRegenerate(oldsid, sid string) (session.Store, error) { c := rp.poollist.Get() defer c.Close() if existed, _ := redis.Int(c.Do("EXISTS", oldsid)); existed == 0 { // oldsid doesn't exists, set the new sid directly // ignore error here, since if it return error // the existed value will be 0 c.Do("SET", sid, "", "EX", rp.maxlifetime) } else { c.Do("RENAME", oldsid, sid) c.Do("EXPIRE", sid, rp.maxlifetime) } return rp.SessionRead(sid) } // SessionDestroy delete redis session by id func (rp *Provider) SessionDestroy(sid string) error { c := rp.poollist.Get() defer c.Close() c.Do("DEL", sid) return nil } // SessionGC Impelment method, no used. func (rp *Provider) SessionGC() { } // SessionAll return all activeSession func (rp *Provider) SessionAll() int { return 0 } func init() { session.Register("redis", redispder) }
SessionStore的Get，Set，Delete，Flush 都是操作自己的字典values （map[interface{}]interface{}），所以在一個具體的api 裡面設定了session 然後獲取 肯定不會串，因為這個時候都還在記憶體 沒有儲存到redis。Provider的SessionInit實際是初始化redis的一些連結資訊，func(rp*Provider)SessionRead(sidstring)(session.Store,error) 這個才是真正載入session的，func(rs*SessionStore)SessionRelease(whttp.ResponseWriter) 才是真生儲存session的。具體在哪裡載入和儲存的了？在router.go的func (p *ControllerRegister) ServeHTTP(rw http.ResponseWriter, r *http.Request) 方法裡面有如下程式碼：
// session init if BConfig.WebConfig.Session.SessionOn { var err error context.Input.CruSession, err = GlobalSessions.SessionStart(rw, r) if err != nil { logs.Error(err) exception("503", context) goto Admin } defer func() { if context.Input.CruSession != nil { context.Input.CruSession.SessionRelease(rw) } }() }
GlobalSessions.SessionStart(rw, r)的實現在session.go的func(manager*Manager)SessionStart(whttp.ResponseWriter,r*http.Request)(sessionStore,errerror)方法裡面， 有如下程式碼：
if sid != "" && manager.provider.SessionExist(sid) {
return manager.provider.SessionRead(sid)
}
// Generate a new session
sid, errs = manager.sessionID()
if errs != nil {
return nil, errs
}
session, err = manager.provider.SessionRead(sid)
if err != nil {
return nil, err
}我們知道在http 請求開始， beego去裝載session，然後在請求方法結束的時候去儲存session。下次獲取的session 就是最近一次儲存的值，而不是最後一次請求的資料。
go的程式碼：
func (c *MainController) V1() {
v := c.GetSession("asta")
time.Sleep(time.Second * 4)
c.SetSession("asta", "v1")
c.Data["json"] = fmt.Sprintf("get session:%s, set session:V1", v)
c.ServeJSON()
}
func (c *MainController) V2() {
v := c.GetSession("asta")
time.Sleep(time.Second * 2)
c.SetSession("asta", "v2")
c.Data["json"] = fmt.Sprintf("get session:%s, set session:V2", v)
c.ServeJSON()
}
func (c *MainController) V3() {
v := c.GetSession("asta")
c.Data["json"] = fmt.Sprintf("get session:%s", v)
c.ServeJSON()
}html程式碼：
<body>
<div>test</div>
<script src="https://cdn.staticfile.org/jquery/1.10.2/jquery.min.js"></script>
<input type="button" value="set session" id="setsession"/><br/>
V1: <p id="txt1"></p><br/>
V2: <p id="txt2"></p><br/>
<input type="button" value="get session" id="getsession"/><br/>
V3: <p id="txt3"></p><br/>
<script>
$("#setsession").click(function(){
$.get("http://localhost:8080/v1",function(data){$("#txt1").html(data) ;});
$.get("http://localhost:8080/v2",function(data){$("#txt2").html(data) ;});
});
$("#getsession").click(function(){
$.get("http://localhost:8080/v3",function(data){$("#txt3").html(data) ;});
});
</script>
</body>先點選setsession呼叫V1和V2， 按理說V1先到達->V2到達->V2返回->V1返回，session最後儲存的是V1的值
【通過列印資訊可以得到如圖】
