Python 系列文章 —— flask 表单案例

from flask import Flask, render_template, redirect, url_for, request

from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField
from wtforms.validators import DataRequired, EqualTo

from werkzeug.security import generate_password_hash
from werkzeug.security import check_password_hash

from flask_login import LoginManager, UserMixin, current_user
from flask_login import logout_user, login_user, login_required

import uuid


app = Flask(__name__)  # 创建 Flask 应用

app.secret_key = 'abc'  # 设置表单交互密钥

login_manager = LoginManager()  # 实例化登录管理对象
login_manager.init_app(app)  # 初始化应用
login_manager.session_protection = 'strong'
login_manager.login_view = 'login'  # 设置用户登录视图函数 endpoint

# 用户数据
USERS = [
    {
        "id": 1,
        "name": 'lily',
        "password": generate_password_hash('123')
    },
    {
        "id": 2,
        "name": 'tom',
        "password": generate_password_hash('123')
    }
]

def create_user(user_name, password):
    """创建一个用户"""
    user = {
        "name": user_name,
        "password": generate_password_hash(password),
        "id": uuid.uuid4()
    }
    USERS.append(user)

def get_user(user_name):
    """根据用户名获得用户记录"""
    for user in USERS:
        if user.get("name") == user_name:
            return user
    return None

class LoginForm(FlaskForm):
    """登录表单类"""
    username = StringField('用户名', validators=[DataRequired()])
    password = PasswordField('密码', validators=[DataRequired()])

class SignupForm(FlaskForm):
    """用户注册表单类"""
    username = StringField('用户名', validators=[DataRequired()])
    password = PasswordField('密码', [
        DataRequired(),
        EqualTo('confirm', message='两次输入的密码不一致')
    ])
    confirm = PasswordField('确认密码')

class User(UserMixin):
    """用户类"""
    def __init__(self, user):
        self.username = user.get("name")
        self.password_hash = user.get("password")
        self.id = user.get("id")

    def verify_password(self, password):
        """密码验证"""
        if self.password_hash is None:
            return False
        return check_password_hash(self.password_hash, password)

    def get_id(self):
        """获取用户ID"""
        return self.id

    @staticmethod
    def get(user_id):
        """根据用户ID获取用户实体，为 login_user 方法提供支持"""
        if not user_id:
            return None
        for user in USERS:
            if user.get('id') == user_id:
                return User(user)
        return None

@login_manager.user_loader  # 定义获取登录用户的方法
def load_user(user_id):
    return User.get(user_id)


@app.route('/signup/', methods=('GET', 'POST'))  # 注册
def signup():
    form = SignupForm()
    emsg = None
    if form.validate_on_submit():
        user_name = form.username.data
        password = form.password.data

        user_info = get_user(user_name)  # 用用户名获取用户信息
        if user_info is None:
            create_user(user_name, password)  # 如果不存在则创建用户
            return redirect(url_for("login"))  # 创建后跳转到登录页
        else:
            emsg = "用户名已存在"  # 如果用户已存在则给出错误提示
    return render_template('signup.html', form=form, emsg=emsg)

@app.route('/login/', methods=('GET', 'POST'))  # 登录
def login():
    form = LoginForm()
    emsg = None
    if form.validate_on_submit():
        user_name = form.username.data
        password = form.password.data
        user_info = get_user(user_name)
        if user_info is None:
            emsg = "用户名或密码密码有误"
        else:
            user = User(user_info)
            if user.verify_password(password):
                login_user(user)
                return redirect(request.args.get('next') or url_for('index'))
            else:
                emsg = "用户名或密码密码有误"
    return render_template('login.html', form=form, emsg=emsg)

@app.route('/')  # 首页
@login_required  # 需要登录才能访问
def index():
    return render_template('index.html', username=current_user.username)

@app.route('/logout')  # 登出
@login_required
def logout():
    logout_user()
    return redirect(url_for('login'))

if __name__ == '__main__':
    app.run(debug=True)

```js

<h1>欢迎 {{ username }}！</h1>

<a href='{{ url_for('logout')}}'>登出</a>

```

- login

```js

{% macro render_field(field) %}

<dt>{{ field.label }}:

<dd>{{ field(**kwargs)|safe }}

{% if field.errors %}

    <ul class=errors>

    {% for error in field.errors %}

    <li>{{ error }}</li>

    {% endfor %}

    </ul>

{% endif %}

</dd>

{% endmacro %}

<!-- <a href="{{ url_for('signup') }}">注册</a> -->

<form method="POST">

    {{ form.csrf_token }}

    {{ render_field(form.username) }}

    {{ render_field(form.password) }}

    {% if emsg %}

        <h3> {{ emsg }}</h3>

    {% endif %}

    <input type="submit" value="登录">

</form>

```

- signup

```js

{% macro render_field(field) %}

<dt>{{ field.label }}:

<dd>{{ field(**kwargs)|safe }}

{% if field.errors %}

    <ul class=errors>

    {% for error in field.errors %}

    <li>{{ error }}</li>

    {% endfor %}

    </ul>

{% endif %}

</dd>

{% endmacro %}

<form method="POST">

    {{ form.csrf_token }}

    {{ render_field(form.username) }}

    {{ render_field(form.password) }}

    {{ render_field(form.confirm) }}

    {% if emsg %}

        <h3> {{ emsg }}</h3>

    {% endif %}

    <input type="submit" value="注册">

</form>