Flask-Login

Flask-Login 提供用户会话管理，处理常见的登录、退出和注册的任务。

Flask-Login 没有绑定数据库,可以从数据库回调用户对象。

安装flask-login

pip install flask-login

结构

|-- app/
|   |-- __init__.py
|   |-- forms.py
|   |-- models.py
|   |-- routes.py
|   `-- templates/
|       |-- base.html
|       |-- index.html
|       |-- login.html
|       `-- register.html
|-- app.db
|-- config.py
`-- microblog.py

环境变量

安装python-dotenv，避免了每次运行代码都要定义环境变量

pip install python-dotenv

根目录新建.flaskenv环境变量文件
.flaskenv：

FLASK_APP=microblog.py

microblog.py:

from app import app, db
from app.models import User, Post@app.shell_context_processor
def make_shell_context():return {'db': db, 'User': User, 'Post': Post}

配置项

import os
basedir = os.path.abspath(os.path.dirname(__file__))class Config(object):SECRET_KEY = os.environ.get('SECRET_KEY') or 'you-will-never-guess'SQLALCHEMY_DATABASE_URI = os.environ.get('DATABASE_URL') or \'sqlite:///' + os.path.join(basedir, 'app.db')SQLALCHEMY_TRACK_MODIFICATIONS = False

app.dp项目运行后产生

初始化模块

app/__init__.py

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_migrate import Migrate
from config import Config
from flask_login import LoginManagerapp = Flask(__name__)
app.config.from_object(Config)
db = SQLAlchemy(app)
migrate = Migrate(app, db)
login = LoginManager(app)
login.login_view = 'login'from app import routes, models

用户加载模块

用户加载模块,完成如下2个功能：

1. 定义用户数据库模型
2. 加载数据库匹配用户

注意事项：

使用Flask-Login的user类必须实现下列属性方法：

如果继承UserMixin类，则默认实现了上述方法；

app/models.py

from datetime import datetime
from app import db, login
from werkzeug.security import generate_password_hash, check_password_hash
from flask_login import UserMixinclass User(UserMixin,db.Model):id = db.Column(db.Integer, primary_key=True)username = db.Column(db.String(64), index=True, unique=True)email = db.Column(db.String(120), index=True, unique=True)password_hash = db.Column(db.String(128))posts = db.relationship('Post', backref='author', lazy='dynamic')def __repr__(self):return '<User {}>'.format(self.username)def set_password(self, password):self.password_hash = generate_password_hash(password)def check_password(self, password):return check_password_hash(self.password_hash, password)@login.user_loader
def load_user(id):return User.query.get(int(id))class Post(db.Model):id = db.Column(db.Integer, primary_key=True)body = db.Column(db.String(140))timestamp = db.Column(db.DateTime, index=True, default=datetime.utcnow)user_id = db.Column(db.Integer, db.ForeignKey('user.id'))def __repr__(self):return '<Post {}>'.format(self.body)

路由和视图函数

• 用户登陆
• 用户注销
• 用户注册

app/routes.py

from flask import render_template, flash, redirect, url_for, request
from flask_login import login_user, logout_user, current_user, login_required
from werkzeug.urls import url_parse
from app import app, db
from app.forms import LoginForm, RegistrationForm
from app.models import User@app.route('/')
@app.route('/index')
@login_required
def index():posts = [{'author': {'username': 'John'},'body': 'Beautiful day in Portland!'},{'author': {'username': 'Susan'},'body': 'The Avengers movie was so cool!'}]return render_template('index.html', title='Home', posts=posts)@app.route('/login', methods=['GET', 'POST'])
def login():if current_user.is_authenticated:return redirect(url_for('index'))form = LoginForm()if form.validate_on_submit():user = User.query.filter_by(username=form.username.data).first()if user is None or not user.check_password(form.password.data):flash('Invalid username or password')return redirect(url_for('login'))login_user(user, remember=form.remember_me.data)next_page = request.args.get('next')if not next_page or url_parse(next_page).netloc != '':next_page = url_for('index')return redirect(next_page)return render_template('login.html', title='Sign In', form=form)@app.route('/logout')
def logout():logout_user()return redirect(url_for('index'))@app.route('/register', methods=['GET', 'POST'])
def register():if current_user.is_authenticated:return redirect(url_for('index'))form = RegistrationForm()if form.validate_on_submit():user = User(username=form.username.data, email=form.email.data)user.set_password(form.password.data)db.session.add(user)db.session.commit()flash('Congratulations, you are now a registered user!')return redirect(url_for('login'))return render_template('register.html', title='Register', form=form)

表单

实现2个功能：

• 登陆验证
• 用户注册

app/forms.py：

from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField, BooleanField, SubmitField
from wtforms.validators import ValidationError, DataRequired, Email, EqualTo
from app.models import Userclass LoginForm(FlaskForm):username = StringField('Username', validators=[DataRequired()])password = PasswordField('Password', validators=[DataRequired()])remember_me = BooleanField('Remember Me')submit = SubmitField('Sign In')class RegistrationForm(FlaskForm):username = StringField('Username', validators=[DataRequired()])email = StringField('Email', validators=[DataRequired(), Email()])password = PasswordField('Password', validators=[DataRequired()])password2 = PasswordField('Repeat Password', validators=[DataRequired(), EqualTo('password')])submit = SubmitField('Register')def validate_username(self, username):user = User.query.filter_by(username=username.data).first()if user is not None:raise ValidationError('Please use a different username.')def validate_email(self, email):user = User.query.filter_by(email=email.data).first()if user is not None:raise ValidationError('Please use a different email address.')

模板

app/templates/base.html：基本模板，用于做父类提供继承

<html><head>{% if title %}<title>{{ title }} - Microblog</title>{% else %}<title>Welcome to Microblog</title>{% endif %}</head><body><div>Microblog:<a href="{{ url_for('index') }}">Home</a>{% if current_user.is_anonymous %}<a href="{{ url_for('login') }}">Login</a>{% else %}<a href="{{ url_for('logout') }}">Logout</a>{% endif %}</div><hr>{% with messages = get_flashed_messages() %}{% if messages %}<ul>{% for message in messages %}<li>{{ message }}</li>{% endfor %}</ul>{% endif %}{% endwith %}{% block content %}{% endblock %}</body>
</html>

app/templates/index.html：起始页面

{% extends "base.html" %}{% block content %}<h1>Hi, {{ current_user.username }}!</h1>{% for post in posts %}<div><p>{{ post.author.username }} says: <b>{{ post.body }}</b></p></div>{% endfor %}
{% endblock %}

app/templates/register.html：用户注册

{% extends "base.html" %}{% block content %}<h1>Register</h1><form action="" method="post">{{ form.hidden_tag() }}<p>{{ form.username.label }}<br>{{ form.username(size=32) }}<br>{% for error in form.username.errors %}<span style="color: red;">[{{ error }}]</span>{% endfor %}</p><p>{{ form.email.label }}<br>{{ form.email(size=64) }}<br>{% for error in form.email.errors %}<span style="color: red;">[{{ error }}]</span>{% endfor %}</p><p>{{ form.password.label }}<br>{{ form.password(size=32) }}<br>{% for error in form.password.errors %}<span style="color: red;">[{{ error }}]</span>{% endfor %}</p><p>{{ form.password2.label }}<br>{{ form.password2(size=32) }}<br>{% for error in form.password2.errors %}<span style="color: red;">[{{ error }}]</span>{% endfor %}</p><p>{{ form.submit() }}</p></form>
{% endblock %}

app/templates/login.html：游客请登陆

{% extends "base.html" %}{% block content %}<h1>Sign In</h1><form action="" method="post" novalidate>{{ form.hidden_tag() }}<p>{{ form.username.label }}<br>{{ form.username(size=32) }}<br>{% for error in form.username.errors %}<span style="color: red;">[{{ error }}]</span>{% endfor %}</p><p>{{ form.password.label }}<br>{{ form.password(size=32) }}<br>{% for error in form.password.errors %}<span style="color: red;">[{{ error }}]</span>{% endfor %}</p><p>{{ form.remember_me() }} {{ form.remember_me.label }}</p><p>{{ form.submit() }}</p></form><p>New User? <a href="{{ url_for('register') }}">Click to Register!</a></p>
{% endblock %}

项目运行

到项目根目录

PS D:\Days\Flask-Login> flask run* Serving Flask-SocketIO app "microblog.py"* Forcing debug mode off* Serving Flask app "microblog.py"* Environment: productionWARNING: Do not use the development server in a production environment.Use a production WSGI server instead.* Debug mode: off* Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
127.0.0.1 - - [30/Nov/2018 11:22:44] "[37mGET /login?next=%2F HTTP/1.1[0m" 200 -

浏览器打开：http://localhost:5000