fa directory created

fa/14.2.md

@@ -0,0 +1,107 @@
+# 14.2 Sessions
+
+In chapter 6, we introduced some basic concepts pertaining to sessions in Go, and we implemented a session manager. The Beego framework uses this session manager to implement some convenient session-handling functionality. 
+
+## Integrating sessions
+
+Beego handles sessions mainly according to the following global variables:
+
+	// related to session
+	SessionOn bool	// whether or not to open the session module. Defaults to false. 
+	SessionProvider string	// the desired session backend processing module. Defaults to an in-memory sessionManager 
+	SessionName string	// the name of the client saved cookies
+	SessionGCMaxLifetime int64	// cookie validity
+
+	GlobalSessions *session.Manager// global session controller
+
+Of course, the values of these variables shown above need to be initialized. You can also use the values from the following configuration file code to set these values:
+
+	if ar, err := AppConfig.Bool("sessionon"); err != nil {
+		SessionOn = false
+	} else {
+		SessionOn = ar
+	}
+	if ar := AppConfig.String("sessionprovider"); ar == "" {
+		SessionProvider = "memory"
+	} else {
+		SessionProvider = ar
+	}
+	if ar := AppConfig.String("sessionname"); ar == "" {
+		SessionName = "beegosessionID"
+	} else {
+		SessionName = ar
+	}
+	if ar, err := AppConfig.Int("sessiongcmaxlifetime"); err != nil && ar != 0 {
+		int64val, _ := strconv.ParseInt(strconv.Itoa(ar), 10, 64)
+		SessionGCMaxLifetime = int64val
+	} else {
+		SessionGCMaxLifetime = 3600
+	}
+
+Add the following code in the `beego.Run` function:
+
+	if SessionOn {
+		GlobalSessions, _ = session.NewManager(SessionProvider, SessionName, SessionGCMaxLifetime)
+		go GlobalSessions.GC()
+	}
+
+As long as `SessionOn` is set to true, it will open the session by default with an independent goroutine session handler 
+
+In order to facilitate our custom Controller quickly using session, the author `beego.Controller` provides the following methods:
+
+To assist us in quickly using sessions in a custom Controller, `beego.Controller` provides the following method:
+
+	func (c *Controller) StartSession() (sess session.Session) {
+		sess = GlobalSessions.SessionStart(c.Ctx.ResponseWriter, c.Ctx.Request)
+		return
+	}		
+
+## Using sessions 
+
+From the code above, we can see that the Beego framework simply inherits its session functionality. So, how do we use it in our projects?   
+
+First of all, we need to open the session at the entry point of our application. 
+
+	beego.SessionOn = true
+
+We can then use the corresponding session method inside our controller like so: 
+
+	func (this *MainController) Get() {
+		var intcount int
+		sess := this.StartSession()
+		count := sess.Get("count")
+		if count == nil {
+			intcount = 0
+		} else {
+			intcount = count.(int)
+		}
+		intcount = intcount + 1
+		sess.Set("count", intcount)
+		this.Data["Username"] = "astaxie"
+		this.Data["Email"] = "astaxie@gmail.com"
+		this.Data["Count"] = intcount
+		this.TplNames = "index.tpl"
+	}
+
+The code above shows how to use sessions in the controller logic. The process can be divided into two steps: 
+
+1. Getting session object
+
+		// Get the object, similar in PHP session_start()
+		sess:= this.StartSession()
+
+2. Using the session for general operations 
+
+		// Get the session values , similar in PHP $ _SESSION ["count"]
+		sess.Get("count")
+		
+		// Set the session value
+		sess.Set("count", intcount)
+
+As you can see, applications based on the Beego framework can easily implement sessions. The process is very similar to calling `session_start()` in PHP applications. 
+
+## Links
+
+- [Directory](preface.md)
+- Previous section: [Static files](14.1.md)
+- Next section: [Forms](14.3.md)