Python之Flask框架

摘自：https://www.cainiaoxueyuan.com/bc/36825.html

Flask安装

 pip install Flask

项目配置

debug模式 Host 端口号

from flask import Flask, request

app = Flask(__name__)

# http://192.168.31.118:5001/
@app.route('/')
def hello_world():  # put application's code here
    return 'Hello World12223!'

# http://192.168.31.118:5001/my
@app.route('/my')
def my():
    return 'My name is Douge'

# http://192.168.31.118:5001/book/list 你获取的是1
# http://192.168.31.118:5001/book/list?page=2 你获取的是2
@app.route('/book/list')
def book_detail():
    page = request.args.get('page',default=1,type=int)
    return '你获取的是{}'.format(page)


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

模版渲染传参

http://192.168.1.225:5001/template/detail_id/1991

from flask import Flask, request, render_template
app = Flask(__name__)
@app.route('/template/detail_id/<detail_id>')
def template(detail_id):  # put application's code here
    return render_template('demo.html', detail_id=detail_id)

模版访问对象

from flask import Flask, request, render_template
app = Flask(__name__)
@app.route('/template/detail_id/<detail_id>')
def template(detail_id):  # put application's code here
    obj = {
        'name':'douge'
    }
    return render_template('demo.html', detail_id=detail_id,obj=obj)

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <div>hello Python{{ detail_id }}</div>
    <div>{{ obj }}</div>
    <div>{{ obj.name }}</div>
</body>
</html>

自定义过滤器

类似Thinkphp模版里面的使用函数

from flask import Flask, request, render_template
app = Flask(__name__)
@app.route('/template')
def template():  # put application's code here
    obj = {
        'name': 'douge'
    }
    return render_template('demo.html', obj=obj)

# 自定义过滤器 
def filter(value):
    return value.upper()
# 增加过滤器
app.add_template_filter(filter, 'filter')

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
{#内置过滤器#}
    <div>{{ obj.name | length}}</div>
{#自定义过滤器#}
    <div>{{ obj.name | filter}}</div>
</body>
</html>

控制语句

from flask import Flask, request, render_template
app = Flask(__name__)
@app.route('/template')
def template():  # put application's code here
    obj = {
        'name': 'douge',
        'age': 18,
        'child': ['1', '2']
    }
    return render_template('demo.html', obj=obj)

<div>
    {{ obj }}
    {#if判断#}
    <div>
        {% if obj.age >= 18 %}可以进入 {% endif %} {% if obj.age < 18 %} 禁止进入{% endif %}
    </div>
    {#for循环#}
     <div>
         {% for foo in obj.child %}
             {{ foo }}
         {% endfor %}
     </div>
 </div>

模版组件穿参

mode.html

 <!DOCTYPE html>
 <html lang="en">
   <head>
     <meta charset="UTF-8" />
     <title>test</title>
   </head>
   <body>
     <div>
         {% extends 'footer.html' %}
         {% block title %} 标题 {% endblock %}
         {% block content %} 内容 {% endblock %}
     </div>
   </body>
 </html>

footer.html

 <!DOCTYPE html>
 <html lang="en">
   <head>
     <meta charset="UTF-8" />
     <title>footer 这是一个组件</title>
   </head>
   <body>
     <h1>footer组件</h1>
     <h2>{% block title %}{% endblock %}</h2>
     <h3>{% block content %}{% endblock %}</h3>
   </body>
 </html>

加载静态文件

  <head>
     <meta charset="UTF-8" />
     <title>test</title>
     {#引入css#}
     <link rel="stylesheet" href='{{ url_for("static",filename="demo.css") }}' />
     {#引入js#}
     <script src='{{ url_for("static",filename="demo.js")}}'></script>
 </head>
<body>
     <div>
         {#引入图片#}
         <img class="text_img" src='{{ url_for("static",filename="test.jpg") }}' alt="" />
     </div>
 </body>

操作数据库(Mysql) 增删改查(CRUD)

pip install pymysql
pip install flask-sqlalchemy

连接数据库

# 从 Flask 这个包中导入 flask 这个类
from flask import Flask, request, render_template
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy import text
app = Flask(__name__)
# 配置文件
HOSTNAME = '103.*.*.36'
PORT = 3306
USERNAME = 'python_test'
DATABASE = 'python_test'
PASSWORD = 'PdpLZMk4F4Z6aYwF'
print('mysql+pymysql://{}:{}@{}:{}/{}?charset=utf8mb4'.format(USERNAME, PASSWORD,HOSTNAME, PORT,DATABASE))
app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql+pymysql://{}:{}@{}:{}/{}?charset=utf8mb4'.format(USERNAME, PASSWORD,HOSTNAME, PORT,DATABASE)
db = SQLAlchemy(app)
with app.app_context():
    with db.engine.connect() as conn:
        rs = conn.execute(text("select 1"))
        print(rs.fetchone()) #输出 (1,)

运行输出

创建数据表

# 从 Flask 这个包中导入 flask 这个类
from flask import Flask, request, render_template
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy import text
app = Flask(__name__)
# 配置文件
HOSTNAME = '103.*.*.36'
PORT = 3306
USERNAME = 'python_test'
DATABASE = 'python_test'
PASSWORD = 'PdpLZMk4F4Z6aYwF'
print('mysql+pymysql://{}:{}@{}:{}/{}?charset=utf8mb4'.format(USERNAME, PASSWORD,HOSTNAME, PORT,DATABASE))
app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql+pymysql://{}:{}@{}:{}/{}?charset=utf8mb4'.format(USERNAME, PASSWORD,HOSTNAME, PORT,DATABASE)
db = SQLAlchemy(app)

# with app.app_context():
#     with db.engine.connect() as conn:
#         rs = conn.execute(text("select 1"))
#         print(rs.fetchone()) # (1,)

# User orm
class User(db.Model):
    # 映射表名
    __tablename__ = 'user'
    # 配置数据库元素
    # id，username，password 的各自的属性（主键，类型，是否可以为空，自增等等）
    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)
# 下面的语句实际上就是映射为 insert 语句
# user = User(username='法外狂徒张三', password='111111')
# 将你创建的表推到数据库
with app.app_context():
    db.create_all()

Create

# 从 Flask 这个包中导入 flask 这个类
from flask import Flask, request, render_template
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy import text

app = Flask(__name__)
# 配置文件
HOSTNAME = '103.*.*.36'
PORT = 3306
USERNAME = 'python_test'
DATABASE = 'python_test'
PASSWORD = 'PdpLZMk4F4Z6aYwF'
print('mysql+pymysql://{}:{}@{}:{}/{}?charset=utf8mb4'.format(USERNAME, PASSWORD, HOSTNAME, PORT, DATABASE))
app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql+pymysql://{}:{}@{}:{}/{}?charset=utf8mb4'.format(USERNAME, PASSWORD,
                                                                                                HOSTNAME, PORT,
                                                                                                DATABASE)
db = SQLAlchemy(app)


# with app.app_context():
#     with db.engine.connect() as conn:
#         rs = conn.execute(text("select 1"))
#         print(rs.fetchone()) # (1,)

# User orm
class User(db.Model):
    # 映射表名
    __tablename__ = 'user'
    # 配置数据库元素
    # id，username，password 的各自的属性（主键，类型，是否可以为空，自增等等）
    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)


# 下面的语句实际上就是映射为 insert 语句
# user = User(username='法外狂徒张三', password='111111')
# 将你创建的表推到数据库
with app.app_context():
    db.create_all()


@app.route('/user/add')
def addUser():
    user = User(username='法外狂徒张三', password='111111')
    db.session.add(user)
    db.session.commit()
    return '新建用户成功'

Read

 @app.route('/user/read')
 def readUser():
     # get 查找:根据主键查找
     user = User.query.get(1)
     return '查找用户成功{}{}'.format(user.id, user.username)
 @app.route('/user/read')
 def readUser():
     # 1.get 查找:根据主键查找
     # user = User.query.get(1)
     # 2.使用 filter_by 查找
     users = User.query.filter_by(username='法外狂徒张三')
     print('this is users', users[0].username)
     return '查找用户成功'

Update

 @app.route('/user/update')
 def updateUser():
     user = User.query.filter_by(username='法外狂徒张三').first()
     user.username = '法外狂徒李嘉俊'
     db.session.commit()
     return '修改用户成功'

Delete

 @app.route('/user/delete')
 def deleteUser():
     # 查找
     user = User.query.filter_by(username='法外狂徒李嘉俊').first()
     # 从 db.session 中删除
     db.session.delete(user)
     # 提交删除
     db.session.commit()
     return '删除用户成功'

ORM模型外键与表关系

# 从 Flask 这个包中导入 flask 这个类
from flask import Flask, request, render_template
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy import text

app = Flask(__name__)
# 配置文件
HOSTNAME = '103.*.*.36'
PORT = 3306
USERNAME = 'python_test'
DATABASE = 'python_test'
PASSWORD = 'PdpLZMk4F4Z6aYwF'
print('mysql+pymysql://{}:{}@{}:{}/{}?charset=utf8mb4'.format(USERNAME, PASSWORD, HOSTNAME, PORT, DATABASE))
app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql+pymysql://{}:{}@{}:{}/{}?charset=utf8mb4'.format(USERNAME, PASSWORD,
                                                                                                HOSTNAME, PORT,
                                                                                                DATABASE)
db = SQLAlchemy(app)


# with app.app_context():
#     with db.engine.connect() as conn:
#         rs = conn.execute(text("select 1"))
#         print(rs.fetchone()) # (1,)

# User orm
class User(db.Model):
    # 映射表名
    __tablename__ = 'user'
    # 配置数据库元素
    # id，username，password 的各自的属性（主键，类型，是否可以为空，自增等等）
    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)


# 下面的语句实际上就是映射为 insert 语句
# user = User(username='法外狂徒张三', password='111111')

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)

    # 添加作者的外键
    author_id = db.Column(db.Integer, db.ForeignKey("user.id"))
    # backref 会自动给User模型添加一个articles的属性 来获取文章列表
    author = db.relationship("User", backref="articles")


# article = Article(title="Jindouyun", content="hello world")
# article.author_id = user.id
# user = user.query.get(article.author_id)
# article.author = User.query.get(article.author_id)
# print(article.author)
# sqlalchemy/flask
# user.articles


# 将你创建的表推到数据库
with app.app_context():
    db.create_all()


@app.route('/user/add')
def addUser():
    user = User(username='法外狂徒张三', password='111111')
    db.session.add(user)
    db.session.commit()
    return '新建用户成功'


@app.route('/article/add')
def article_add():
    article = Article(title="Jindouyun", content="hello world")
    article.author = User.query.get(1)

    article1 = Article(title="Jindouyun1", content="hello world1")
    article1.author = User.query.get(1)
    db.session.add_all([article, article1])
    # 同步到数据库
    db.session.commit()
    return '文章插入成功'

# http://192.168.1.7:5001/article/query
@app.route('/article/query')
def query_article():
    user = User.query.get(1);
    for article in user.articles:
        print(article.title)
    return "文章查询成功!"

#  * Debugger is active!
#  * Debugger PIN: 931-355-907
# Jindouyun
# Jindouyun1

posted @ 2023-06-24 19:56 窦戈阅读(60) 评论(0) 编辑收藏举报

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Python之Flask框架

Flask安装

项目配置

debug模式 Host 端口号

模版渲染 传参

模版访问对象

自定义过滤器

控制语句

模版组件穿参

mode.html

footer.html

加载静态文件

操作数据库(Mysql) 增删改查(CRUD)

连接数据库

运行输出

创建数据表

Create

Read

Update

Delete

ORM模型外键与表关系

模版渲染传参