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 Flask

app = Flask(__name__)

@app.route('/')
def index():
    return 'Hello world'

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

2.debug、host、port配置

from flask import Flask,request

app = 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,request

app = 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 Migrate

app = 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 Migrate

app = 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.id
    article.author = user

    db.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 Migrate

app = 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 SQLAlchemy

db = SQLAlchemy()

2.User模型搭建

model.py

from exts import db
from datetime import datetime

class 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_template

auth = Blueprint('auth', __name__, url_prefix='/auth')


@auth.route('/register')
def register():
    return render_template('register.html')