rtu_linux_services/web-ui.service/web_session.go

package main

import (
	"crypto/rand"
	"encoding/hex"
	"net/http"
	"sync"
	"time"
)

type sessionInfo struct {
	last time.Time
}

var (
	sessionMu sync.Mutex
	sessions  = make(map[string]*sessionInfo)
)

// 默认5分钟无任何页面点击操作时, 超时
const idleTimeout = 5 * time.Minute

func createSession() string {
	buf := make([]byte, 32)
	rand.Read(buf)
	return hex.EncodeToString(buf)
}

func addSession(id string) {
	sessionMu.Lock()
	sessions[id] = &sessionInfo{last: time.Now()}
	sessionMu.Unlock()
}

func hasSession(id string) bool {
	now := time.Now()

	sessionMu.Lock()
	defer sessionMu.Unlock()

	s, ok := sessions[id]
	if !ok {
		return false
	}

	if now.Sub(s.last) > idleTimeout {
		delete(sessions, id)
		return false
	}

	s.last = now
	return true
}

func checkSession(r *http.Request) bool {
	c, err := r.Cookie("session_id")
	if err != nil {
		return false
	}
	return hasSession(c.Value)
}

func sessionCleaner() {
	ticker := time.NewTicker(3 * time.Minute)
	defer ticker.Stop()

	for range ticker.C {
		now := time.Now()
		sessionMu.Lock()
		for k, s := range sessions {
			if now.Sub(s.last) > idleTimeout {
				delete(sessions, k)
			}
		}
		sessionMu.Unlock()
	}
}