app_old.txt

import os
import sys

from flask import Flask , render_template
from flask import request, url_for, redirect, flash
from flask_sqlalchemy import SQLAlchemy
from markupsafe import escape
import click
from werkzeug.security import generate_password_hash, check_password_hash
from flask_login import LoginManager,UserMixin , login_user, logout_user, login_required, current_user

WIN = sys.platform.startswith('win')
if WIN:  # 如果是 Windows 系统，使用三个斜线
    prefix = 'sqlite:///'
else:  # 否则使用四个斜线
    prefix = 'sqlite:////'

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = prefix + os.path.join(app.root_path, 'data.db')
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False  # 关闭对模型修改的监控
app.config['SECRET_KEY'] =  os.getenv('SECRET_KEY', 'dev')

db = SQLAlchemy(app)
login_manager = LoginManager(app)
login_manager.login_view = 'login' #登录视图端点（函数名）

@login_manager.user_loader
def load_user(user_id):  # 创建用户加载回调函数，接受用户 ID 作为参数
    user = User.query.get(int(user_id))  # 用 ID 作为 User 模型的主键查询对应的用户
    return user  # 返回用户对象

class User(db.Model , UserMixin):  # 表名将会是 user（自动生成，小写处理）
    id = db.Column(db.Integer, primary_key=True)  # 主键
    name = db.Column(db.String(20))  
    username = db.Column(db.String(20))  # 用户名
    password_hash = db.Column(db.String(128))  # 密码散列值

    def set_password(self, password):  # 用来设置密码的方法，接受密码作为参数
        self.password_hash = generate_password_hash(password)  # 将生成的密码保持到对应字段
    def validate_password(self, password):  # 用于验证密码的方法，接受密码作为参数
        return check_password_hash(self.password_hash, password)  

class Movie(db.Model):  # 表名将会是 movie
    id = db.Column(db.Integer, primary_key=True)  # 主键
    title = db.Column(db.String(60))  # 电影标题
    year = db.Column(db.String(4))  # 电影年份
    
@app.cli.command()
def forge():
    '''generate fake data'''
    names = ['Joe Nie','Reveynn Dong']
    movies = [
        {'title': 'My Neighbor Totoro', 'year': '1988'},
        {'title': 'Dead Poets Society', 'year': '1989'},
        {'title': 'A Perfect World', 'year': '1993'},
        {'title': 'Leon', 'year': '1994'},
        {'title': 'Mahjong', 'year': '1996'},
        {'title': 'Swallowtail Butterfly', 'year': '1996'},
        {'title': 'King of Comedy', 'year': '1999'},
        {'title': 'Devils on the Doorstep', 'year': '1999'},
        {'title': 'WALL-E', 'year': '2008'},
        {'title': 'The Pork of Music', 'year': '2012'},
    ]
    for name in names:
        user = User(name=name)
        db.session.add(user)
    for m in movies:
        movie = Movie(title=m['title'], year=m['year'])
        db.session.add(movie)
    db.session.commit()
    click.echo('Done.')  # 输出提示信息

@app.route('/' )
def hello():
    return render_template('home.html')
    # return '<h1>Hello Totoro!</h1><img src="http://helloflask.com/totoro.gif">'

@app.context_processor #上下文处理函数
def inject_user():  # 函数名可以随意修改
    user = User.query.first()
    return dict(user=user)  # 需要返回字典，等同于 return {'user': user}

@app.route('/index', methods=['GET', 'POST'])
def index():
    if request.method == 'POST' :
        if not current_user.is_authenticated:  # 如果当前用户未认证
            return redirect(url_for('index'))  # 重定向到主页
        title = request.form.get('title')
        year = request.form.get('year')
        if not title or not year or len(title) > 60 or len(year) != 4:
            flash('Invalid input.')
            return redirect(url_for('index'))
        movie = Movie(title=title, year=year)
        db.session.add(movie)
        db.session.commit()
        flash('Movie added.')
        return redirect(url_for('index'))
    # user = User.query.first()
    movies = Movie.query.all()
    return render_template('index.html', movies=movies)

@app.route('/movie/delete/<int:movie_id>', methods=['POST'])  # 限定只接受 POST 请求
@login_required 
def delete(movie_id):
    movie = Movie.query.get_or_404(movie_id)  # 获取电影记录
    db.session.delete(movie)  # 删除对应的记录
    db.session.commit()  # 提交数据库会话
    flash('Item deleted.')
    return redirect(url_for('index'))  # 重定向回主页

@app.route('/movie/edit/<int:movie_id>', methods=['GET', 'POST'])
@login_required 
def edit(movie_id):
    movie = Movie.query.get_or_404(movie_id)  # 获取电影记录
    if request.method == 'POST':
        title = request.form.get('title')
        year = request.form.get('year')
        if not title or not year or len(title) > 60 or len(year) != 4:
            flash('Invalid input.')
            return redirect(url_for('edit', movie_id=movie_id))
        movie.title = title
        movie.year = year
        db.session.commit()
        flash('Item updated.')
        return redirect(url_for('index'))
    return render_template('edit.html', movie=movie)


# @app.route('/index/<name>')
# def index_(name):
#     return render_template('index.html', name=escape(name), movies=movies)

@app.errorhandler(404)
def page_not_found(e):
    return render_template('404.html'), 404
    

@app.cli.command()  # 注册为命令，可以传入 name 参数来自定义命令
@click.option('--drop', is_flag=True, help='Create after drop.')  # 设置选项
def initdb(drop):
    """Initialize the database."""
    if drop:  # 判断是否输入了选项
        db.drop_all()
    db.create_all()
    click.echo('Initialized database.')  # 输出提示信息
    
@app.cli.command()
@click.option('--username', prompt=True, help='The username used to login.')
@click.option('--password', prompt=True, hide_input=True, confirmation_prompt=True, help='The password used to login.')
def admin(username, password):
    """Create user."""
    db.create_all()
    user = User.query.first()
    if user is not None:
        click.echo('Updating user...')
        user.username = username
        user.set_password(password)
    else:
        click.echo('Creating user...')
        user = User(username=username , name = 'admin')
        user.set_password(password)
        db.session.add(user)
    db.session.commit()
    click.echo('Done.')
    
@app.route('/login', methods=['GET', 'POST'])
def login():
    if request.method == 'POST':
        username = request.form['username']
        password = request.form['password']

        if not username or not password:
            flash('Invalid input.')
            return redirect(url_for('login'))

        user = User.query.first()
        # 验证用户名和密码是否一致
        if username == user.username and user.validate_password(password):
            login_user(user)  # 登入用户
            flash('Login success.')
            return redirect(url_for('index'))  # 重定向到主页
        flash('Invalid username or password.')  # 如果验证失败，显示错误消息
        return redirect(url_for('login'))  # 重定向回登录页面

    return render_template('login.html')

@app.route('/logout')
@login_required  # 用于视图保护，后面会详细介绍
def logout():
    logout_user()  # 登出用户
    flash('Goodbye.')
    return redirect(url_for('index'))  # 重定向回首页

@app.route('/settings', methods=['GET', 'POST'])
@login_required
def settings():
    if request.method == 'POST':
        name = request.form['name']

        if not name or len(name) > 20:
            flash('Invalid input.')
            return redirect(url_for('settings'))

        current_user.name = name
        # current_user 会返回当前登录用户的数据库记录对象
        # 等同于下面的用法
        # user = User.query.first()
        # user.name = name
        db.session.commit()
        flash('Settings updated.')
        return redirect(url_for('index'))

    return render_template('settings.html')