【Flask】用户身份认证

Flask 用户身份认证

前提条件

bash 复制代码

# flask-bcrypt 用户密码加密存储
pip install flask_bcrypt -i https://pypi.tuna.tsinghua.edu.cn/simple/
# flask提供的用户登录方法
pip install flask_login -i https://pypi.tuna.tsinghua.edu.cn/simple/

用户注册

后端方法：

python 复制代码

@app.route("/register", methods=["GET", "POST"])
def register_page():
    form = RegisterForm()
    if form.validate_on_submit():
        # 创建用户
        user_to_create = User(username=form.username.data,
                              email_address=form.email.data,
                              password=form.password1.data)
        db.session.add(user_to_create)
        db.session.commit()
        print("用户{username}创建成功".format(username=form.username.data))
        return redirect(url_for('login_page'))
    if form.errors != {}:
        for err_msg in form.errors.values():
            print("{}".format(err_msg))
            flash(f"There was an error with creating account:{err_msg}", category="danger")
    return render_template("register.html", form=form)

模型方法：

python 复制代码

# @property 获取用户密码属性
# @password.setter 设置用户密码
from market import bcrypt

class User(db.Model, UserMixin):
    id = db.Column(db.Integer(), primary_key=True)
    username = db.Column(db.String(length=30), nullable=False, unique=True)
    email_address = db.Column(db.String(length=50), nullable=False, unique=True)
    password_hash = db.Column(db.String(length=60), nullable=False)
    budget = db.Column(db.Integer(), nullable=False, default=1000)
    items = db.relationship('Item', backref='owned_user', lazy=True)

    @property
    def password(self):
        return self.password

    @password.setter
    def password(self, plain_text_password):
        self.password_hash = bcrypt.generate_password_hash(plain_text_password).decode('utf-8')

前端页面：

html 复制代码

{% extends "base.html" %}
{% block title%}
Register Page
{% endblock %}
{% block content%}
<body>
    <div class="container">
        <form method="POST" class="form-register" style="color:white">
            {{ form.hidden_tag() }}
            <img class="mb-4" src="{{ url_for('static', filename='img/euansu.png') }}" style="width: 100px;height: 100px;margin-top: 30px;"/>
            <h1 class="h3 mb-3 font-weight-normal">
                Please Create your Account
            </h1>

            {{ form.username.label() }}
            {{ form.username(class="form-control", placeholder="User Name") }}

            {{ form.email.label() }}
            {{ form.email(class="form-control", placeholder="Email Address") }}

            {{ form.password1.label() }}
            {{ form.password1(class="form-control", placeholder="Password") }}

            {{ form.password2.label() }}
            {{ form.password2(class="form-control", placeholder="Confirm Password") }}
            <br />
            {{form.submit(class="btn btn-lg btn-block btn-primary")}}
        </form>
    </div>
</body>



{% endblock %}

页面实现：

用户注册，成功后跳转至登录页面

用户登录

后端方法：

python 复制代码

from market.forms import LoginForm
from flask_login import login_user, login_required

# 需要登录后才能访问的页面，添加 login_required 装饰器
@app.route("/market")
@login_required
def market_page():
    items = Item.query.all()
    return render_template("market.html", items=items)

@app.route('/login', methods=['GET', 'POST'])
def login_page():
    form = LoginForm()
    if form.validate_on_submit():
        attempted_user = User.query.filter_by(username=form.username.data).first()
        if attempted_user and attempted_user.check_password_correction(attempted_password=form.password.data):
            login_user(attempted_user)
            flash(f'Success! You are logged in as: {attempted_user.username}', category='success')
            return redirect(url_for('market_page'))
        else:
            flash('Username and password are not match! Please try again', category='danger')
    return render_template('login.html', form=form)

# 这里用到了一个表单，需要实现在forms.py，也即你自己的表单文件中进行定义
from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField, SubmitField
from wtforms.validators import Length, EqualTo, Email, DataRequired

class LoginForm(FlaskForm):
    username = StringField(label='User Name:', validators=[DataRequired()])
    password = PasswordField(label='Password:', validators=[DataRequired()])
    submit = SubmitField(label='Sign in')

模型文件也需要队用户对象做一些修改，否则直接使用 flask 自带的 login_user 会报如下的错误：

python 复制代码

from market import db,login_manager
from market import bcrypt
from flask_login import UserMixin
# 添加如下内容
@login_manager.user_loader
def load_user(user_id):
    return User.query.get(int(user_id))
# User对象需要继承UserMixin类
class User(db.Model,UserMixin):
    id = db.Column(db.Integer(), primary_key=True)
    username = db.Column(db.String(length=30), nullable=False, unique=True)
    email_address = db.Column(db.String(length=50), nullable=False, unique=True)
    password_hash = db.Column(db.String(length=60), nullable=False)
    budget = db.Column(db.Integer(), nullable=False, default=1000)
    items = db.relationship('Item', backref='owned_user', lazy=True)

    @property
    def password(self):
        return self.password

    @password.setter
    def password(self, plain_text_password):
        self.password_hash = bcrypt.generate_password_hash(plain_text_password).decode('utf-8')
    # 这里是用来判断用户输入的密码是否正确
    def check_password_correction(self, attempted_password):
        return bcrypt.check_password_hash(self.password_hash, attempted_password)

前端文件：

html 复制代码

{% extends 'base.html' %}
{% block title %}
    Login Page
{% endblock %}

{% block content %}
<body>
    <div class="container">
        <form method="POST" class="form-signin" style="color:white">
            {{ form.hidden_tag() }}
            <img class="mb-4" src="{{ url_for('static', filename='img/euansu.png') }}" style="width: 100px;height: 100px;margin-top: 30px;"/>
            <h1 class="h3 mb-3 font-weight-normal">
                Please Login
            </h1>
            <br>
            {{ form.username.label() }}
            {{ form.username(class="form-control", placeholder="User Name") }}

            {{ form.password.label() }}
            {{ form.password(class="form-control", placeholder="Password") }}

            <br>
            <div class="checkbox mb-3">
               <h6>Do not have an account?</h6>
               <a class="btn btn-sm btn-secondary" href="{{ url_for('register_page') }}">Register</a>
            </div>

            {{ form.submit(class="btn btn-lg btn-block btn-primary") }}

        </form>
    </div>
</body>
{% endblock %}

实现效果：

输入密码错误，页面报错。

输入密码正确，跳转进入 market 页面。

直接访问 market 页面报错，提示缺少所需要的用户信息。

注销登录

后端方法：

python 复制代码

from flask_login import logout_user

@app.route('/logout')
def logout_page():
    logout_user()
    flash("You have been logged out!", category='info')
    return redirect(url_for("home_page"))

前端页面：

原来的 header 这里有 Login 和 Register 两个方法，这里修改一下，如果用户已经登录，这里修改为 Logout，修改后的代码如下：

python 复制代码

{% if current_user.is_authenticated %}
<ul class="navbar-nav">
    <li class="nav-item">
        <a class="nav-link" style="color: lawngreen; font-weight: bold">
            <i class="fas fa-coins"></i>
            {{ current_user.prettier_budget }}
        </a>
    </li>
    <li class="nav-item">
        <a class="nav-link">Welcome, {{ current_user.username }}</a>
    </li>
    <li class="nav-item">
        <a class="nav-link" href="{{ url_for('logout_page') }}">Logout</a>
    </li>
</ul>
{% else %}
<ul class="navbar-nav">
    <li class="nav-item">
        <a class="nav-link" href="{{ url_for('login_page') }}">Login</a>
    </li>
    <li class="nav-item">
        <a class="nav-link" href="{{ url_for('register_page') }}">Register</a>
    </li>
</ul>
{% endif %}

实现效果：

点击 Logout 调用 logout_page 方法，效果如下：