使用大猩猩会话时，golang中的会话变量未保存

Question

使用大猩猩会话网络工具包时，不会跨请求维护会话变量。当我启动服务器并输入localhost：8100
/时，由于会话值不存在，页面被定向到login.html。登录后，我在商店中设置了会话变量，页面被重定向到home.html。但是，当我打开一个新选项卡并键入localhost：8100
/时，应使用已存储的会话变量将页面定向到home.html，但应将页面重定向到login.html。以下是代码。

    package main

import (
    "crypto/md5"
    "encoding/hex"
    "fmt"
    "github.com/gocql/gocql"
    "github.com/gorilla/mux"
    "github.com/gorilla/sessions"
    "net/http"
    "time"
)

var store = sessions.NewCookieStore([]byte("something-very-secret"))

var router = mux.NewRouter()

func init() {

    store.Options = &sessions.Options{
        Domain:   "localhost",
        Path:     "/",
        MaxAge:   3600 * 1, // 1 hour
        HttpOnly: true,
    }
}
func main() {
    //session handling
    router.HandleFunc("/", SessionHandler)
    router.HandleFunc("/signIn", SignInHandler)
    router.HandleFunc("/signUp", SignUpHandler)
    router.HandleFunc("/logOut", LogOutHandler)
    http.Handle("/", router)
    http.ListenAndServe(":8100", nil)
}

//handler for signIn
func SignInHandler(res http.ResponseWriter, req *http.Request) {

    email := req.FormValue("email")
    password := req.FormValue("password")

    //Generate hash of password
    hasher := md5.New()
    hasher.Write([]byte(password))
    encrypted_password := hex.EncodeToString(hasher.Sum(nil))

    //cassandra connection
    cluster := gocql.NewCluster("localhost")
    cluster.Keyspace = "gbuy"
    cluster.DefaultPort = 9042
    cluster.Consistency = gocql.Quorum
    session, _ := cluster.CreateSession()
    defer session.Close()

    //select query
    var firstname string
    stmt := "SELECT firstname FROM USER WHERE email= '" + email + "' and password ='" + encrypted_password + "';"
    err := session.Query(stmt).Scan(&firstname)
    if err != nil {
        fmt.Fprintf(res, "failed")
    } else {
        if firstname == "" {
            fmt.Fprintf(res, "failed")
        } else {
            fmt.Fprintf(res, firstname)
        }
    }

    //store in session variable
    sessionNew, _ := store.Get(req, "loginSession")

    // Set some session values.
    sessionNew.Values["email"] = email
    sessionNew.Values["name"] = firstname

    // Save it.
    sessionNew.Save(req, res)
    //store.Save(req,res,sessionNew)

    fmt.Println("Session after logging:")
    fmt.Println(sessionNew)

}

//handler for signUp
func SignUpHandler(res http.ResponseWriter, req *http.Request) {

    fName := req.FormValue("fName")
    lName := req.FormValue("lName")
    email := req.FormValue("email")
    password := req.FormValue("passwd")
    birthdate := req.FormValue("date")
    city := req.FormValue("city")
    gender := req.FormValue("gender")

    //Get current timestamp and format it.
    sysdate := time.Now().Format("2006-01-02 15:04:05-0700")

    //Generate hash of password
    hasher := md5.New()
    hasher.Write([]byte(password))
    encrypted_password := hex.EncodeToString(hasher.Sum(nil))

    //cassandra connection
    cluster := gocql.NewCluster("localhost")
    cluster.Keyspace = "gbuy"
    cluster.DefaultPort = 9042
    cluster.Consistency = gocql.Quorum
    session, _ := cluster.CreateSession()
    defer session.Close()

    //Insert the data into the Table
    stmt := "INSERT INTO USER (email,firstname,lastname,birthdate,city,gender,password,creation_date) VALUES ('" + email + "','" + fName + "','" + lName + "','" + birthdate + "','" + city + "','" + gender + "','" + encrypted_password + "','" + sysdate + "');"
    fmt.Println(stmt)
    err := session.Query(stmt).Exec()
    if err != nil {
        fmt.Fprintf(res, "failed")
    } else {
        fmt.Fprintf(res, fName)
    }
}

//handler for logOut
func LogOutHandler(res http.ResponseWriter, req *http.Request) {
    sessionOld, err := store.Get(req, "loginSession")

    fmt.Println("Session in logout")
    fmt.Println(sessionOld)
    if err = sessionOld.Save(req, res); err != nil {
        fmt.Println("Error saving session: %v", err)
    }
}

//handler for Session
func SessionHandler(res http.ResponseWriter, req *http.Request) {

    router.PathPrefix("/").Handler(http.FileServer(http.Dir("../static/")))
    session, _ := store.Get(req, "loginSession")

    fmt.Println("Session in SessionHandler")
    fmt.Println(session)


    if val, ok := session.Values["email"].(string); ok {
        // if val is a string
        switch val {
        case "": {
            http.Redirect(res, req, "html/login.html", http.StatusFound) }
        default:
            http.Redirect(res, req, "html/home.html", http.StatusFound)
        }
    } else {
        // if val is not a string type
        http.Redirect(res, req, "html/login.html", http.StatusFound)
    }
}

有人可以告诉我我在做什么错。提前致谢。

Answer 1

首先： 永远不要使用md5哈希密码。阅读有关原因的文章，然后使用Go的bcrypt包。您还应该参数化您的SQL查询，否则您将 遭受灾难性的 SQL注入攻击。

无论如何：您需要在此处解决一些问题：

• 您的会话不是“固定”的，而是您将Pathas 设置为/loginSession-因此，当用户访问任何其他路径（即/）时，该会话对该范围无效。

您应该在程序初始化时设置会话存储，并在其中设置选项：

var store = sessions.NewCookieStore([]byte("something-very-secret"))

func init() {

   store.Options = &sessions.Options{
    Domain:   "localhost",
    Path:     "/",
    MaxAge:   3600 * 8, // 8 hours
    HttpOnly: true,
}

您可能设置更具体路径的原因是，如果登录用户始终在子路由之内，例如/accounts。就您而言，这不是正在发生的事情。

我应该补充一下，Web检查器中的Chrome的“资源”选项卡（“资源”>“
Cookie”）对于调试此类问题非常有用，因为您可以看到Cookie的有效期，路径和其他设置。

• 您还在检查session.Values["email"] == nil，这是行不通的。Go中的一个空字符串是just ""，并且由于session.Values是a map[string]interface{}，因此需要将assert值键入一个字符串：

即

if val, ok := session.Values["email"].(string); ok {
      // if val is a string
      switch val {
             case "":
                 http.Redirect(res, req, "html/login.html", http.StatusFound)
             default:
                 http.Redirect(res, req, "html/home.html", http.StatusFound)
      }
    } else {
        // if val is not a string type
        http.Redirect(res, req, "html/login.html", http.StatusFound)
    }

我们处理“不是字符串”的情况，因此我们很明确地说明如果会话不是我们期望的那样，程序应该怎么做（客户端对其进行了修改，或者我们程序的较旧版本使用了不同的类型）。

• 保存会话时，您没有检查错误。

  sessionNew.Save(req, res)
  

… 应该：

    err := sessionNew.Save(req, res)
    if err != nil {
            // handle the error case
    }

• SessionHandler 在 提供静态文件 之前 ，您应该先获取/验证会话（但是，这样做的方式非常round回）：

  func SessionHandler(res http.ResponseWriter, req *http.Request) {
  session, err := store.Get(req, "loginSession")
  if err != nil {
      // Handle the error
  }
  
  if session.Values["email"] == nil {
      http.Redirect(res, req, "html/login.html", http.StatusFound)
  } else {
     http.Redirect(res, req, "html/home.html", http.StatusFound)
  }
  // This shouldn't be here - router isn't scoped in this function! You should set this in your main() and wrap it with a function that checks for a valid session.
  router.PathPrefix("/").Handler(http.FileServer(http.Dir("../static/")))
  

  }