Flow/go/src/flowserver/sessionmanager.go

package flowserver

import (
	"encoding/json"
	"log"
	"net/http"
	"sync"

	"github.com/gorilla/websocket"
)

//FlowSessionManager or FlowServerCore
type FlowSessionManager struct {
	// List of flow sessions?
	sessions map[string]*FlowSession

	sync.Mutex
}

//New creates a New initialized FlowSessionManager
func New() *FlowSessionManager {
	return &FlowSessionManager{
		sessions: map[string]*FlowSession{},
	}
}
func (fsm *FlowSessionManager) CreateSession() *FlowSession {
	fsm.Lock()
	defer fsm.Unlock()
	for {
		ID := RandString(10)
		sess, ok := fsm.sessions[ID]
		if !ok {
			fsm.sessions[ID] = sess
			return sess
		}
	}

}

//LoadSession loads or creates a new Session
func (fsm *FlowSessionManager) LoadSession(ID string) *FlowSession {
	fsm.Lock()
	defer fsm.Unlock()

	log.Println("Fetching session:", ID)
	sess, ok := fsm.sessions[ID]
	if !ok {
		sess = &FlowSession{ID: ID}
		fsm.sessions[ID] = sess
	}
	return sess

}

// FlowMessage Main message structure
type FlowMessage struct {
	OP   string          `json:"op"`
	Data json.RawMessage `json:"data"`
}

var upgrader = websocket.Upgrader{}

func (fsm *FlowSessionManager) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	log.Println("Receiving ws connection")
	c, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		log.Println("upgrade:", err)
	}
	defer c.Close()

	/////////////////
	// Message handling
	// ////////

	for {
		mt, data, err := c.ReadMessage()
		if err != nil {
			log.Println("Err:", err)
			break
		}
		if mt != websocket.TextMessage {
			log.Println("Not a text message?")
			break
		}

		fmsg := FlowMessage{}
		err = json.Unmarshal(data, &fmsg)
		if err != nil {
			log.Println("Err parsing message:", err)
			c.WriteJSON("bye")
		}
		switch fmsg.OP {
		case "newSession":
			log.Println("We want a new session so")
			sess := fsm.LoadSession("")
			sess.clients = append(sess.clients, c)
		}
		// Create a Session, assign us to session

		// Switch kind of mesasge etc here
		// Acquire session ID, and send all the info
		// Write msg
		// Create or Load a session

	}
	log.Println("ws Is disconnecting")

}