Python密码管理器代码报错排查：Tkinter回调及SQL语法等3类错误

问题描述 #

开发Python密码管理器时，解决之前的2个问题后仍出现3类错误：

• Tkinter回调异常（此前已存在），报错栈指向tkinter/__init__.py的__call__方法；
• checkPassword函数调用getmasterPassword()时出现异常；
• getmasterPassword中的SQLite语句存在语法错误，提示near "password": syntax error。

详细报错信息 #

1. C:\Users####\PycharmProjects\pythonProject8\main.py
   Exception in Tkinter callback
   Traceback (most recent call last):
   File "C:\Users####\AppData\Local\Programs\Python\Python311\Lib\tkinter_init_.py", line 1948, in call
   return self.func(*args)
   ^^^^^^^^^^^^^^^^
2. File "C:\Users####\PycharmProjects\pythonProject8\main.py", line 78, in checkPassword
   match = getmasterPassword()
   ^^^^^^^^^^^^^^^^^^^
3. File "C:\Users####\PycharmProjects\pythonProject8\main.py", line 73, in getmasterPassword
   cursor.execute("SELECT * FROM masterpassword WHERE id = 1 password= ?", [check_hashed_password])
   sqlite3.OperationalError: near "password": syntax error

错误原因与修复步骤 #

1. SQLite语法错误（核心触发点） #

getmasterPassword函数的SQL查询语句中，WHERE子句的两个条件id=1和password=?之间缺少逻辑运算符AND，直接导致SQL语法错误。
修复前代码：

cursor.execute("SELECT * FROM masterpassword WHERE id = 1 password = ?", [(checkHashedPassword)])

修复后代码：

cursor.execute("SELECT * FROM masterpassword WHERE id = 1 AND password = ?", [checkHashedPassword])

2. 密码存储与验证的逻辑错误 #

• savePassword函数中，hashedPassword = txt.get仅引用了方法对象，未调用get()获取输入值，且未使用导入的hashlib进行密码哈希（明文存储不安全）：
  修复前：

  hashedPassword = txt.get
  

  修复后：

  hashedPassword = hashlib.sha256(txt.get().encode()).hexdigest()
  

• getmasterPassword函数中，需对用户输入的密码进行同样的哈希处理，才能与数据库中存储的哈希值匹配：
  修复后代码片段：

  input_password = txt.get()
  hashed_input = hashlib.sha256(input_password.encode()).hexdigest()
  cursor.execute("SELECT * FROM masterpassword WHERE id = 1 AND password = ?", [hashed_input])
  

3. Tkinter回调异常 #

该异常是由上述SQL错误和逻辑错误导致的——当Tkinter回调函数（如checkPassword）执行时抛出未捕获的异常，就会触发回调异常。修复上述所有错误后，该异常会自动消失。

完整修正后的代码 #

import sqlite3
import hashlib
from tkinter import *

# 数据库初始化
with sqlite3.connect("password_vault.db") as db:
    cursor = db.cursor()

# 创建主密码表（如果不存在）
cursor.execute("""
CREATE TABLE IF NOT EXISTS masterpassword(
id INTEGER PRIMARY KEY,
password TEXT NOT NULL);
""")

window = Tk()
window.title("Password Vault")

def firstScreen():
    window.geometry("250x175")

    lbl = Label(window, text="Create Master Password")
    lbl.config(anchor=CENTER)
    lbl.pack()

    # 密码输入框隐藏显示内容
    txt = Entry(window, width=20, show="*")
    txt.pack()
    txt.focus()

    lbl1 = Label(window, text="Re-Enter Password")
    lbl1.pack()

    txt1 = Entry(window, width=20, show="*")
    txt1.pack()
    txt1.focus()

    lbl2 = Label(window)
    lbl2.pack()

    def savePassword():
        if txt.get() == txt1.get():
            # 对密码进行SHA256哈希加密
            hashedPassword = hashlib.sha256(txt.get().encode()).hexdigest()
            insert_password = """INSERT INTO masterpassword(password) VALUES(?)"""
            cursor.execute(insert_password, [hashedPassword])
            db.commit()
            passwordVault()
        else:
            lbl2.config(text="Passwords do not match")

    btn = Button(window, text="Save", command=savePassword)
    btn.pack(pady=10)

def loginScreen():
    window.geometry("250x100")

    lbl = Label(window, text="Enter Master Password")
    lbl.config(anchor=CENTER)
    lbl.pack()

    txt = Entry(window, width=20, show="*")
    txt.pack()
    txt.focus()

    lbl1 = Label(window)
    lbl1.pack()

    def getmasterPassword():
        # 获取输入密码并哈希
        input_password = txt.get()
        hashed_input = hashlib.sha256(input_password.encode()).hexdigest()
        # 修复SQL语法错误：添加AND连接条件
        cursor.execute("SELECT * FROM masterpassword WHERE id = 1 AND password = ?", [hashed_input])
        return cursor.fetchall()

    def checkPassword():
        try:
            match = getmasterPassword()
            if match:
                passwordVault()
            else:
                txt.delete(0, END)
                lbl1.config(text="Wrong Password")
        except Exception as e:
            lbl1.config(text=f"Error: {str(e)}")

    btn = Button(window, text="Submit", command=checkPassword)
    btn.pack(pady=10)

def passwordVault():
    # 清空当前界面所有组件
    for widget in window.winfo_children():
        widget.destroy()
    window.geometry("700x350")
    lbl = Label(window, text="Password Vault")
    lbl.config(anchor=CENTER)
    lbl.pack()

# 判断是否已有主密码，决定进入登录或创建界面
cursor.execute("SELECT * FROM masterpassword")
if cursor.fetchall():
    loginScreen()
else:
    firstScreen()

window.mainloop()

内容的提问来源于stack exchange，提问作者noodle