Golang实现用户登录系统教程

type User struct {
    Username string
    Password string // 存储哈希值
}

var users = make(map[string]User) // 内存存储，key 为用户名

import "golang.org/x/crypto/bcrypt"

func hashPassword(password string) (string, error) {
    bytes, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
    return string(bytes), err
}

func checkPassword(hash, password string) bool {
    err := bcrypt.CompareHashAndPassword([]byte(hash), []byte(password))
    return err == nil
}

func register(username, password string) error {
    if _, exists := users[username]; exists {
        return fmt.Errorf("用户已存在")
    }
    hashed, err := hashPassword(password)
    if err != nil {
        return err
    }
    users[username] = User{Username: username, Password: hashed}
    return nil
}

func login(username, password string) bool {
    user, exists := users[username]
    if !exists {
        return false
    }
    return checkPassword(user.Password, password)
}

func registerHandler(w http.ResponseWriter, r *http.Request) {
    if r.Method == "POST" {
        username := r.FormValue("username")
        password := r.FormValue("password")
        if err := register(username, password); err != nil {
            http.Error(w, err.Error(), http.StatusBadRequest)
            return
        }
        w.Write([]byte("注册成功"))
        return
    }
    w.Write([]byte(`
        

            用户名: 

            密码: 

            
        
    `))
}

func loginHandler(w http.ResponseWriter, r *http.Request) {
    if r.Method == "POST" {
        username := r.FormValue("username")
        password := r.FormValue("password")
        if login(username, password) {
            w.Write([]byte("登录成功！"))
            return
        }
        http.Error(w, "用户名或密码错误", http.StatusUnauthorized)
        return
    }
    w.Write([]byte(`
        

            用户名: 

            密码: 

            
        
    `))
}

func main() {
    http.HandleFunc("/register", registerHandler)
    http.HandleFunc("/login", loginHandler)
    http.ListenAndServe(":8080", nil)
}