Restruct (#34)

* modify

* remove

* modify

* modify

* remove no use

* add online/offline notification

* modify

* format log

* add reference

broker/sesson.go

@@ -0,0 +1,53 @@
+package broker
+
+import "github.com/eclipse/paho.mqtt.golang/packets"
+
+func (b *Broker) getSession(cli *client, req *packets.ConnectPacket, resp *packets.ConnackPacket) error {
+	// If CleanSession is set to 0, the server MUST resume communications with the
+	// client based on state from the current session, as identified by the client
+	// identifier. If there is no session associated with the client identifier the
+	// server must create a new session.
+	//
+	// If CleanSession is set to 1, the client and server must discard any previous
+	// session and start a new one. b session lasts as long as the network c
+	// onnection. State data associated with b session must not be reused in any
+	// subsequent session.
+
+	var err error
+
+	// Check to see if the client supplied an ID, if not, generate one and set
+	// clean session.
+
+	if len(req.ClientIdentifier) == 0 {
+		req.CleanSession = true
+	}
+
+	cid := req.ClientIdentifier
+
+	// If CleanSession is NOT set, check the session store for existing session.
+	// If found, return it.
+	if !req.CleanSession {
+		if cli.session, err = b.sessionMgr.Get(cid); err == nil {
+			resp.SessionPresent = true
+
+			if err := cli.session.Update(req); err != nil {
+				return err
+			}
+		}
+	}
+
+	// If CleanSession, or no existing session found, then create a new one
+	if cli.session == nil {
+		if cli.session, err = b.sessionMgr.New(cid); err != nil {
+			return err
+		}
+
+		resp.SessionPresent = false
+
+		if err := cli.session.Init(req); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}