知了传课Flask学习（持续更新）

一、基础内容

1.Flask快速应用

pip install flask

from flask import Flaskapp = Flask(__name__)@app.route('/')
def index():return 'Hello world'if __name__ == '__main__':app.run()

2.debug、host、port配置

from flask import Flask,requestapp = Flask(__name__)@app.route('/')
def index():return 'Hello'if __name__ == '__main__':# debug模型：实时修改更新代码# 修改host：修改主机号# 修改port：修改端口号app.run(debug=True,host='localhost',port=8080)

3.URL与视图的映射

from flask import Flask,requestapp = Flask(__name__)@app.route('/')
def index():return 'Hello'@app.route('/profile')
def profile():return '我是个人中心'@app.route('/blog/<int:id>')
def blog_detail(id):return f'您访问的博客是{id}'# /book/list：返回第一页数据
# /book/list?page=2：返回第二页数据
@app.route('/book/list')
def book_list():page = request.args.get('page',default=1,type=int)return  f'您获取的是第{page}页图书列表'if __name__ == '__main__':# debug模型：实时修改更新代码# 修改host：修改主机号# 修改port：修改端口号app.run(debug=True,host='localhost',port=8080)

4.Flask连接MySQL数据库

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy import text
from flask_migrate import Migrateapp = Flask(__name__)HOSTNAME = '127.0.0.1'
PORT = 3306
USERNAME = 'root'
PASSWORD = 'root'
DATABASE = 'test'
app.config['SQLALCHEMY_DATABASE_URI'] = f"mysql+pymysql://{USERNAME}:{PASSWORD}@{HOSTNAME}:{PORT}/{DATABASE}?charset=utf8mb4"# app.config设置好连接数据库的信息
# 使用SQLAlchemy(app)创建一个db对象db = SQLAlchemy(app)
migrate = Migrate(app, db)# 测试链接
with app.app_context():with db.engine.connect() as conn:query = text("select 1")  # 使用text函数创建可执行的对象rs = conn.execute(query)print(rs.fetchone())@app.route('/')
def hello_world():return "hello world"if __name__ == '__main__':app.run()

5.ORM与表的映射

class User(db.Model):__tablename__ = "user"id = db.Column(db.Integer,primary_key=True,autoincrement=True)username = db.Column(db.String(100),nullable=False)password = db.Column(db.String(100),nullable=False)

6.ORM的增删改查

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy import text
from flask_migrate import Migrateapp = Flask(__name__)HOSTNAME = '127.0.0.1'
PORT = 3306
USERNAME = 'root'
PASSWORD = 'root'
DATABASE = 'test'
app.config['SQLALCHEMY_DATABASE_URI'] = f"mysql+pymysql://{USERNAME}:{PASSWORD}@{HOSTNAME}:{PORT}/{DATABASE}?charset=utf8mb4"# app.config设置好连接数据库的信息
# 使用SQLAlchemy(app)创建一个db对象db = SQLAlchemy(app)
migrate = Migrate(app, db)# 测试链接
with app.app_context():with db.engine.connect() as conn:query = text("select 1")  # 使用text函数创建可执行的对象rs = conn.execute(query)print(rs.fetchone())class User(db.Model):__tablename__ = "user"id = db.Column(db.Integer,primary_key=True,autoincrement=True)username = db.Column(db.String(100),nullable=False)password = db.Column(db.String(100),nullable=False)@app.route('/user/add')
def add_user():user = User(username='yld',password='123456')db.session.add(user)db.session.commit()return '用户创建成功'@app.route('/user/query')
def query_user():# 1.get查找 根据主键查找user = User.query.get(1)print(f'{user.username}')return '数据查找成功'# 2.filter_by查找users = User.query.filter_by(username = 'yld')for i in users:print(i.id)return '数据查找成功'@app.route('/user/update')
def update_user():users = User.query.filter_by(username = 'yld').first()users.password = '222222'db.session.commit()return '数据修改成功'@app.route('/user/delete')
def delete_user():users = User.query.filter_by(username = 'yld').first()db.session.delete(users)db.session.commit()return '数据删除成功'class Article(db.Model):__tablename__ = 'article'id = db.Column(db.Integer,primary_key=True,autoincrement=True)title = db.Column(db.String(200),nullable=False)content = db.Column(db.Text,nullable=False)#添加作者外键author_id = db.Column(db.Integer,db.ForeignKey('user.id'))#backref:自动给User模型添加一个articles属性，用来获取文章列表author = db.relationship('User',backref='articles')@app.route('/article/add')
def article_add():article = Article(title='Flask学习', content='数据库')user = User.query.filter_by(username = 'yld').first()article.author_id = user.idarticle.author = userdb.session.add(article)db.session.commit()return '文章添加成功'@app.route('/')
def hello_world():return "hello world"if __name__ == '__main__':app.run()

二、内容实战

1.博客平台项目搭建

①app.py

from flask import Flask
import config
from exts import db
from models import UserModel
from blueprints.qa import qa
from blueprints.auth import auth
from flask_migrate import Migrateapp = Flask(__name__)app.config.from_object(config)db.init_app(app)
migrate = Migrate(app,db)app.register_blueprint(auth)
app.register_blueprint(qa)if __name__ == '__main__':app.run(debug=True)

②config.py

HOSTNAME = '127.0.0.1'
PORT = 3306
USERNAME = 'root'
PASSWORD = 'root'
DATABASE = 'test'DB_URI =  f"mysql+pymysql://{USERNAME}:{PASSWORD}@{HOSTNAME}:{PORT}/{DATABASE}?charset=utf8mb4"SQLALCHEMY_DATABASE_URI = DB_URI

③exts.py

from flask_sqlalchemy import SQLAlchemydb = SQLAlchemy()

2.User模型搭建

model.py

from exts import db
from datetime import datetimeclass UserModel(db.Model):__tablename__ = 'user'id = db.Column(db.Integer,primary_key=True,autoincrement=True)username = db.Column(db.String(100),nullable=False)password = db.Column(db.String(100),nullable=False)email = db.Column(db.String(100),nullable=False,unique=True)join_time = db.Column(db.DateTime,default=datetime.now)

迁移命令：

flask db init

flask db migrate

flask db upgrade

3.注册页面渲染

①register.html

<!DOCTYPE html>
<html><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1"><link rel="stylesheet" href="{{url_for('static',filename='bootstrap/bootstrap.4.6.min.css')}}"><link rel="stylesheet" href="{{url_for('static',filename='css/init.css')}}"><title>知了问答平台-注册</title>
</head><body><nav class="navbar navbar-expand-lg navbar-light bg-light"><div class="container"><a class="navbar-brand" href="#">知了问答</a><button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent"aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation"><span class="navbar-toggler-icon"></span></button><div class="collapse navbar-collapse" id="navbarSupportedContent"><ul class="navbar-nav mr-auto"><li class="nav-item active"><a class="nav-link" href="/">首页 <span class="sr-only">(current)</span></a></li><li class="nav-item"><a class="nav-link" href="#">发布问答</a></li><li class="nav-item ml-2"><form class="form-inline my-2 my-lg-0" method="GET" action="#"><input class="form-control mr-sm-2" type="search" placeholder="关键字" aria-label="Search"name="q"><button class="btn btn-outline-success my-2 my-sm-0" type="submit">搜索</button></form></li></ul><ul class="navbar-nav"><li class="nav-item"><a class="nav-link" href="#">登录</a></li><li class="nav-item"><a class="nav-link" href="#">注册</a></li></ul></div></div></nav><div class="container"><div class="row mt-4"><div class="col"></div><div class="col"><form method="POST" action="#"><div class="form-group"><label for="exampleInputEmail1">邮箱</label><input type="email" class="form-control" id="exampleInputEmail1" aria-describedby="emailHelp"name="email"><small id="emailHelp" class="form-text text-muted">我们不会把邮箱用于其他用户</small></div><div class="form-group"><label for="exampleInputEmail1">验证码</label><div class="input-group"><input type="text" class="form-control" name="captcha"><div class="input-group-append"><button class="btn btn-outline-secondary" type="button" id="captcha-btn">获取验证码</button></div></div></div><div class="form-group"><label for="exampleInputEmail1">用户名</label><input type="text" class="form-control" name="username"></div><div class="form-group"><label for="exampleInputPassword1">密码</label><input type="password" class="form-control" id="exampleInputPassword1" name="password"></div><div class="form-group"><label for="exampleInputPassword1">确认密码</label><input type="password" class="form-control" name="password_confirm"></div><button type="submit" class="btn btn-primary btn-block">立即注册</button></form></div><div class="col"></div></div></div>
</body></html>

②auth.py

from flask import Blueprint, render_templateauth = Blueprint('auth', __name__, url_prefix='/auth')@auth.route('/register')
def register():return render_template('register.html')