使用flask实现修改密码功能

首先，需要引入 Flask 和相关的模块：

from flask import Flask, render_template, request, redirect, url_for, flash
from flask_sqlalchemy import SQLAlchemy
from werkzeug.security import generate_password_hash, check_password_hash

然后，需要创建 Flask 应用程序实例，并且设置数据库连接：

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///users.db'
app.config['SECRET_KEY'] = 'your_secret_key'
db = SQLAlchemy(app)

接下来，定义用户数据模型：

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(50), unique=True)
    password = db.Column(db.String(100))

然后，定义修改密码的路由和视图函数：

@app.route('/change_password', methods=['GET', 'POST'])
def change_password():
    if request.method == 'POST':
        current_password = request.form['current_password']
        new_password = request.form['new_password']
        confirm_password = request.form['confirm_password']
        
        user = User.query.filter_by(username=session['username']).first()
        if check_password_hash(user.password, current_password):
            if new_password == confirm_password:
                user.password = generate_password_hash(new_password)
                db.session.commit()
                flash('Password changed successfully!', 'success')
                return redirect(url_for('profile'))
            else:
                flash('New password and confirm password do not match!', 'error')
        else:
            flash('Current password is incorrect!', 'error')
    
    return render_template('change_password.html')

最后，在 HTML 模板文件中添加表单：

{% extends 'base.html' %}

{% block content %}
  <h1>Change Password</h1>
  {% with messages = get_flashed_messages() %}
    {% if messages %}
      <ul class="messages">
        {% for message in messages %}
          <li class="{{ message[0] }}">{{ message[1] }}</li>
        {% endfor %}
      </ul>
    {% endif %}
  {% endwith %}
  <form method="post">
    <label for="current_password">Current Password:</label>
    <input type="password" name="current_password" id="current_password" required>
    <br>
    <label for="new_password">New Password:</label>
    <input type="password" name="new_password" id="new_password" required>
    <br>
    <label for="confirm_password">Confirm Password:</label>
    <input type="password" name="confirm_password" id="confirm_password" required>
    <br>
    <input type="submit" value="Change Password">
  </form>
{% endblock %}

这样就完成了使用 Flask 实现修改密码功能。需要注意的是，密码需要使用哈希函数进行加密，以保护用户的隐私。