flask框架-大结局

Posted 2020-11-23 gaimo

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flask-script

　　用于实现类似于django中 python3 manage.py runserver ...类似的命令。

安装

pip3 install flask-script

使用：

from flask_script import Manager
app = Flask(__name__)
manager=Manager(app)
@app.route("/")
def index()
　　return "hello world"

if __name__ == ‘__main__‘:
    manager.run()
#以后在执行，直接：python3 manage.py runserver
#python3 manage.py runserver --help

启动服务器

技术图片

自定义命令

from flask_script import Manager
from flask import Flask
# 安装pip3 install flask-script

app = Flask(__name__)
manager = Manager(app)

@app.route("/")
def index():
    return "hello world"

@manager.command
def func(arg,a):
    print(arg,a)

@manager.option(‘-n‘,‘--name‘,dest=‘name‘)
@manager.option(‘-u‘,‘--url‘,dest=‘url‘)
def cmd(name,url):
    """
    自定义命令（-n也可以写成--name）
    执行：python3 manage.py cmd -n jack -u http://www.baidu.com
    执行： python manage.py  cmd --name lqz --url http://www.oldboyedu.com
    :param name:
    :param url:
    :return:
    """
    print(name,url)
if __name__ == ‘__main__‘:
    manager.run()

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cmd终端输入命令

技术图片

多app应用

from werkzeug.wsgi import DispatcherMiddleware
from werkzeug.serving import run_simple
from flask import Flask, current_app
app1 = Flask(‘app01‘)
app2 = Flask(‘app02‘)

@app1.route(‘/index‘)
def index():
    return "app01"

@app2.route(‘/index2‘)
def index2():
    return "app2"

# http://www.oldboyedu.com/index
# http://www.oldboyedu.com/sec/index2
dm = DispatcherMiddleware(app1, {
    ‘/sec‘: app2,
})

if __name__ == "__main__":
    run_simple(‘localhost‘, 5000, dm)

分析

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路由的访问

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.wtforms

　　表单验证

安装：

pip3 install wtforms

使用：

from flask import Flask, render_template, request, redirect
from wtforms import Form
from wtforms.fields import simple
from wtforms import validators
from wtforms import widgets

app = Flask(__name__)

app.debug = True


class LoginForm(Form):
    # 字段（内部包含正则表达式）
    name = simple.StringField(
        label=‘用户名‘,
        validators=[
            validators.DataRequired(message=‘用户名不能为空.‘),
            validators.Length(min=2, max=6, message=‘用户名长度必须大于%(min)d且小于%(max)d‘)
        ],
        widget=widgets.TextInput(), # 页面上显示的插件
        render_kw={‘class‘: ‘form-control‘}
    )
    # 字段（内部包含正则表达式）
    pwd = simple.PasswordField(
        label=‘密码‘,
        validators=[
            validators.DataRequired(message=‘密码不能为空.‘),
            validators.Length(min=8, message=‘密码长度必须大于%(min)d‘),
            # validators.Regexp(regex="^(?=.*[a-z])(?=.*[A-Z])(?=.*d)(?=.*[$@$!%*?&])[A-Za-zd$@$!%*?&]{8,}",
            #                   message=‘密码至少8个字符，至少1个大写字母，1个小写字母，1个数字和1个特殊字符‘)

        ],
        widget=widgets.PasswordInput(),
        render_kw={‘class‘: ‘form-control‘}
    )

@app.route(‘/login‘, methods=[‘GET‘, ‘POST‘])
def login():
    if request.method == ‘GET‘:
        form = LoginForm()
        return render_template(‘login.html‘, form=form)
    else:
        form = LoginForm(formdata=request.form)
        if form.validate():
            print(‘用户提交数据通过格式验证，提交的值为：‘, form.data)
        else:
            print(form.errors)
        return render_template(‘login.html‘, form=form)

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

login.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h1>登录</h1>
<form method="post">
    <p>{{form.name.label}} {{form.name}} {{form.name.errors[0] }}</p>

    <p>{{form.pwd.label}} {{form.pwd}} {{form.pwd.errors[0] }}</p>
    <input type="submit" value="提交">
</form>
</body>
</html>

效果：

技术图片

使用2：

　　邮箱，单选框，多选框，下拉选框，全局钩子校验密码的实现。

from flask import Flask, render_template, request, redirect
from wtforms import Form
from wtforms.fields import core
from wtforms.fields import html5
from wtforms.fields import simple
from wtforms import validators
from wtforms import widgets

app = Flask(__name__, template_folder=‘templates‘)
app.debug = True

class RegisterForm(Form):

    def validate_pwd_confirm(self, field):
        """
        自定义pwd_confirm字段规则，例：与pwd字段是否一致
        :param field:
        :return:
        """
        # 最开始初始化时，self.data中已经有所有的值
        print(field.data)
        if field.data !="sb":
            #raise validators.ValidationError("sb")  # 继续后续验证
            raise validators.StopValidation("SB")  # 不再继续后续验证

        # if field.data != self.data[‘pwd‘]:
        #     raise validators.ValidationError("密码不一致") # 继续后续验证
            #raise validators.StopValidation("密码不一致")  # 不再继续后续验证

    name = simple.StringField(
        label=‘用户名‘,
        validators=[
            validators.DataRequired()
        ],
        widget=widgets.TextInput(),
        render_kw={‘class‘: ‘form-control‘},
        default=‘Eason‘
    )

    pwd = simple.PasswordField(
        label=‘密码‘,
        validators=[
            validators.DataRequired(message=‘密码不能为空.‘)
        ],
        widget=widgets.PasswordInput(),
        render_kw={‘class‘: ‘form-control‘}
    )

    pwd_confirm = simple.PasswordField(
        label=‘重复密码‘,
        validators=[
            validate_pwd_confirm,
            validators.DataRequired(message=‘重复密码不能为空.‘),
            #validators.EqualTo(‘pwd‘, message="两次密码输入不一致")
        ],
        widget=widgets.PasswordInput(),
        render_kw={‘class‘: ‘form-control‘}
    )

    email = html5.EmailField(
        label=‘邮箱‘,
        validators=[
            validators.DataRequired(message=‘邮箱不能为空.‘),
            validators.Email(message=‘邮箱格式错误‘)
        ],
        widget=widgets.TextInput(input_type=‘email‘),
        render_kw={‘class‘: ‘form-control‘}
    )

    gender = core.RadioField(
        label=‘性别‘,
        choices=(
            (1, ‘男‘),
            (2, ‘女‘),
        ),
        coerce=int # “1” “2”
     )
    city = core.SelectField(
        label=‘城市‘,
        choices=(
            (‘bj‘, ‘北京‘),
            (‘sh‘, ‘上海‘),
        )
    )

    hobby = core.SelectMultipleField(
        label=‘爱好‘,
        choices=(
            (1, ‘篮球‘),
            (2, ‘足球‘),
        ),
        coerce=int
    )

    favor = core.SelectMultipleField(
        label=‘喜好‘,
        choices=(
            (1, ‘篮球‘),
            (2, ‘足球‘),
        ),
        widget=widgets.ListWidget(prefix_label=False),
        option_widget=widgets.CheckboxInput(),
        coerce=int,
        default=[1, 2]
    )

    def __init__(self, *args, **kwargs):
        super(RegisterForm, self).__init__(*args, **kwargs)
        self.favor.choices = ((1, ‘篮球‘), (2, ‘足球‘), (3, ‘羽毛球‘))
        self.favor.data=[1,]

@app.route(‘/register‘, methods=[‘GET‘, ‘POST‘])
def register():
    if request.method == ‘GET‘:
        form = RegisterForm(data={‘gender‘: 2,‘hobby‘:[1,]}) # initial
        return render_template(‘register.html‘, form=form)
    else:
        form = RegisterForm(formdata=request.form)
        if form.validate():
            print(‘用户提交数据通过格式验证，提交的值为：‘, form.data)
        else:
            print(form.errors)
        return render_template(‘register.html‘, form=form)


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

register.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h1>用户注册</h1>
<form method="post" novalidate style="padding:0  50px">
    {% for field in form %}
    <p>{{field.label}}: {{field}} {{field.errors[0] }}</p>
    {% endfor %}
    <input type="submit" value="提交">
</form>
</body>
</html>

前台渲染效果

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.SQLALlchemy

学习内容：

1、介绍

2、简单使用（能创建表，删除表，不能修改表）

3、一对多的关系

4、多对多关系

5、操作数据表

6、基于scoped_session实现线程安全

7、基本的增删改查

8、常用的操作

9、执行原生的mysql

10、一对多

11、多对多

12、Flask-SQLAlchemy

介绍

　　SQLAlchemy是一个基于Python实现的ORM框架。该框架建立在 DB API之上，使用关系对象映射进行数据库操作，

简言之便是：将类和对象转换成SQL，然后使用数据API执行SQL并获取执行结果。

安装

pip3 install sqlalchemy

重要的参数说明

#Engine，框架的引擎
#Connection Pooling ，数据库连接池
#Dialect，选择连接数据库的DB API种类
#Schema/Types，架构和类型
#SQL Exprression Language，SQL表达式语言

　　SQLAlchemy本身无法操作数据库，其必须以来pymsql等第三方插件，Dialect用于和数据API进行交流，

根据配置文件的不同调用不同的数据库API，从而实现对数据库的操作，如：

MySQL-Python
    mysql+mysqldb://<user>:<password>@<host>[:<port>]/<dbname>
    
pymysql
    mysql+pymysql://<username>:<password>@<host>/<dbname>[?<options>]
    
MySQL-Connector
    mysql+mysqlconnector://<user>:<password>@<host>[:<port>]/<dbname>

1、简单使用（能创建表，删除表，不能修改表）

　执行原生sql(不常用)

import time
import threading
import sqlalchemy
from sqlalchemy import create_engine
from sqlalchemy.engine.base import Engine

engine = create_engine(
    "mysql+pymysql://root:123456@127.0.0.1:3306/test?charset=utf8",
    max_overflow=0,  # 超过连接池大小外最多创建的连接
    pool_size=5,  # 连接池大小
    pool_timeout=30,  # 池中没有线程最多等待的时间，否则报错
    pool_recycle=-1  # 多久之后对线程池中的线程进行一次连接的回收（重置）
)
def task(arg):
    conn = engine.raw_connection()
    cursor = conn.cursor()
    cursor.execute(
        "select * from app01_book"
    )
    result = cursor.fetchall()
    print(result)
    cursor.close()
    conn.close()

for i in range(20):
    t = threading.Thread(target=task, args=(i,))
    t.start()

orm使用

　　models.py

import datetime
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, Text, ForeignKey, DateTime, UniqueConstraint, Index
from sqlalchemy.orm import relationship
Base = declarative_base()

class Users(Base):
    __tablename__ = ‘users‘  # 数据库表名称
    id = Column(Integer, primary_key=True)  # id 主键
    name = Column(String(32), index=True, nullable=False)  # name列，索引，不可为空
    #email = Column(String(32), unique=True)
    age = Column(Integer,default=0)
    #datetime.datetime.now不能加括号，加了括号，以后永远是当前时间
    #ctime = Column(DateTime, default=datetime.datetime.now)
    #extra = Column(Text, nullable=True)

    # __table_args__ = (
    #     UniqueConstraint(‘id‘, ‘name‘, name=‘uix_id_name‘), #联合唯一
    #     Index(‘ix_id_name‘, ‘name‘, ‘email‘), #索引
    # )
    def __repr__(self):
        return self.name


class Hobby(Base):
    __tablename__ = ‘hobby‘
    id = Column(Integer, primary_key=True)
    caption = Column(String(50), default=‘篮球‘)


class Person(Base):
    __tablename__ = ‘person‘
    nid = Column(Integer, primary_key=True)
    name = Column(String(32), index=True, nullable=True)
    # hobby指的是tablename而不是类名，
    hobby_id = Column(Integer, ForeignKey("hobby.id"))
    # 跟数据库无关，不会新增字段，只用于快速链表操作
    # 类名，backref用于反向查询,uselist=False
    hobby = relationship(‘Hobby‘, backref=‘pers‘)
    def __repr__(self):
        return self.name


class Boy2Girl(Base):
    __tablename__ = ‘boy2girl‘
    id = Column(Integer, primary_key=True, autoincrement=True)
    girl_id = Column(Integer, ForeignKey(‘girl.id‘))
    boy_id = Column(Integer, ForeignKey(‘boy.id‘))


class Girl(Base):
    __tablename__ = ‘girl‘
    id = Column(Integer, primary_key=True)
    name = Column(String(64), unique=True, nullable=False)


class Boy(Base):
    __tablename__ = ‘boy‘

    id = Column(Integer, primary_key=True, autoincrement=True)
    hostname = Column(String(64), unique=True, nullable=False)

    # 与生成表结构无关，仅用于查询方便,放在哪个单表中都可以
    girl = relationship(‘Girl‘, secondary=‘boy2girl‘, backref=‘boys‘)


def init_db():
    """
    根据类创建数据库表
    :return:
    """
    engine = create_engine(
        "mysql+pymysql://root:123@127.0.0.1:3306/flask?charset=utf8",
        max_overflow=0,  # 超过连接池大小外最多创建的连接
        pool_size=5,  # 连接池大小
        pool_timeout=30,  # 池中没有线程最多等待的时间，否则报错
        pool_recycle=-1  # 多久之后对线程池中的线程进行一次连接的回收（重置）
    )

    Base.metadata.create_all(engine)

def drop_db():
    """
    根据类删除数据库表
    :return:
    """
    engine = create_engine(
        "mysql+pymysql://root:123@127.0.0.1:3306/flask?charset=utf8",
        max_overflow=0,  # 超过连接池大小外最多创建的连接
        pool_size=5,  # 连接池大小
        pool_timeout=30,  # 池中没有线程最多等待的时间，否则报错
        pool_recycle=-1  # 多久之后对线程池中的线程进行一次连接的回收（重置）
    )

    Base.metadata.drop_all(engine)

if __name__ == ‘__main__‘:
    #drop_db()
    init_db()

app.py

　　操作数据库

from sqlalchemy.orm import sessionmaker
from sqlalchemy import create_engine
from models import Users
#"mysql+pymysql://root@127.0.0.1:3306/aaa"
engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/flask", max_overflow=0, pool_size=5)
Connection = sessionmaker(bind=engine)

# 每次执行数据库操作时，都需要创建一个Connection
con = Connection()

# ############# 执行ORM操作 #############
obj1 = Users(name="jack",age=20)
con.add(obj1)
# 提交事务
con.commit()

# 关闭session，其实是将连接放回连接池
con.close()

基于scoped_session实现线程安全

　　关于数据库连接时每次都要提交commint带来的线程安全问题

from sqlalchemy.orm import sessionmaker
from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session
from models import Users

engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/flask", max_overflow=0, pool_size=5)
Session = sessionmaker(bind=engine)

"""
# 线程安全，基于本地线程实现每个线程用同一个session
# 特殊的：scoped_session中有原来方法的Session中的一下方法：

public_methods = (
    ‘__contains__‘, ‘__iter__‘, ‘add‘, ‘add_all‘, ‘begin‘, ‘begin_nested‘,
    ‘close‘, ‘commit‘, ‘connection‘, ‘delete‘, ‘execute‘, ‘expire‘,
    ‘expire_all‘, ‘expunge‘, ‘expunge_all‘, ‘flush‘, ‘get_bind‘,
    ‘is_modified‘, ‘bulk_save_objects‘, ‘bulk_insert_mappings‘,
    ‘bulk_update_mappings‘,
    ‘merge‘, ‘query‘, ‘refresh‘, ‘rollback‘,
    ‘scalar‘
)
"""
#scoped_session类并没有继承Session,但是却又它的所有方法
session = scoped_session(Session)
# ############# 执行ORM操作 #############
obj1 = Users(name="jason")
session.add(obj1)

# 提交事务
session.commit()
# 关闭session
session.close()

单表操作，简单的增删改查

import time
import threading
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Index
from sqlalchemy.orm import sessionmaker, relationship
from sqlalchemy import create_engine
from sqlalchemy.sql import text

from models import Users
engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/flask", max_overflow=0, pool_size=5)
Session = sessionmaker(bind=engine)

session = Session()

# ################ 添加 ################
# obj1 = Users(name="Eason",age=20)
# session.add(obj1)
#
# # session.add_all([
# #     Users(name="tank"),
# #     Users(name="jason"),
# #     #Hosts(name="c1.com"),
# ])
# session.commit()

# ################ 删除 ################
# session.query(Users).filter(Users.id == 5).delete()
# session.commit()
# ################ 修改 ################

#传字典
#session.query(Users).filter(Users.id ==4 ).update({"age" : 30,})
#类似于django的F查询
#session.query(Users).filter(Users.id == 3).update({Users.name: Users.name + "sb"}, synchronize_session=False)
#session.query(Users).filter(Users.id == 7).update({"age": Users.age + 16}, synchronize_session="evaluate")
# session.commit()

# ################ 查询 ################

# r1 = session.query(Users).all()
# print(r1)
#只取age列，把name重命名为xx
# r2 = session.query(Users.name.label(‘sb‘), Users.age).filter(Users.id==8).first()
# print(r2.sb)
#filter传的是表达式，filter_by传的是参数
# r3 = session.query(Users).filter(Users.name == "jason").all()
# print(r3)
# r4 = session.query(Users).filter_by(name=‘jason‘).all()
# print(r4)
# r5 = session.query(Users).filter_by(name=‘lqz‘).first()
#:value 和:name 相当于占位符，用params传参数
#r6 = session.query(Users).filter(text("id<:value and name=:name")).params(value=224, name=‘fred‘).order_by(Users.id).all()
#自定义查询sql
#r7 = session.query(Users).from_statement(text("SELECT * FROM users where name=:name")).params(name=‘ed‘).all()

#增，删，改都要commit()
session.close()

一对多关系

import time
import threading

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Index
from sqlalchemy.orm import sessionmaker, relationship
from sqlalchemy import create_engine
from sqlalchemy.sql import text
from sqlalchemy.engine.result import ResultProxy
from models import Users, Hobby, Person

engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/flask?charset=utf8", max_overflow=0, pool_size=5)
Session = sessionmaker(bind=engine)
session = Session()
# 添加

# session.add_all([
#     Hobby(caption=‘乒乓球‘),
#     Hobby(caption=‘羽毛球‘),
#     Person(name=‘张三‘, hobby_id=1),
#     Person(name=‘李四‘, hobby_id=2),
# ])

# person = Person(name=‘张九‘, hobby=Hobby(caption=‘姑娘‘))
# session.add(person)
#添加二
# hb = Hobby(caption=‘人妖‘)
# hb.pers = [Person(name=‘文飞‘), Person(name=‘博雅‘)]
# session.add(hb)
#
# session.commit()
"""

# 使用relationship正向查询
"""
# v = session.query(Person).first()
# print(v.name)
# print(v.hobby.caption)
"""

# 使用relationship反向查询
"""
# v = session.query(Hobby).first()
# print(v.caption)
# print(v.pers)

#方式一，自己链表
# person_list=session.query(Person).join(Hobby,isouter=True)
# print(person_list)
# person_list=session.query(Person,Hobby).join(Hobby,isouter=True)
# print(person_list)
# for row in person_list:
#     # print(row.name,row.caption)
#     print(row[0].name,row[1].caption)
#
# #方式二：通过relationship
#
person_list=session.query(Person).all()
for row in person_list:
    print(row.name,row.hobby.caption)
# #查询喜欢姑娘的所有人
# obj=session.query(Hobby).filter(Hobby.id==1).first()
# persons=obj.pers
# print(persons)
# session.close()
#如果没有建立外键

# ret = session.query(Person).join(Hobby,Person.nid==Hobby.id, isouter=True)
# print(ret)

多对多关系

import time
import threading

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Index
from sqlalchemy.orm import sessionmaker, relationship
from sqlalchemy import create_engine
from sqlalchemy.sql import text
from sqlalchemy.engine.result import ResultProxy
from models import Users,  Hobby, Person, Girl, Boy2Girl, Boy

engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/flask?charset=utf8", max_overflow=0, pool_size=5)
Session = sessionmaker(bind=engine)
session = Session()
# 添加
# session.add_all([
#     Girl(name=‘c1.com‘),
#     Girl(name=‘c2.com‘),
#     Boy(hostname=‘A组‘),
#     Boy(hostname=‘B组‘),
# ])
# session.commit()

# s2g = Boy2Girl(girl_id=1,boy_id=1)
# session.add(s2g)
# session.commit()
#
# gp = Girl(name=‘C组‘)
# gp.boys = [Boy(hostname=‘c3.com‘),Boy(hostname=‘c4.com‘)]
# session.add(gp)
# session.commit()
#
# ser = Boy(hostname=‘c6.com‘)
# ser.girl = [Girl(name=‘F组‘),Girl(name=‘G组‘)]
# session.add(ser)
# session.commit()

# 使用relationship正向查询

# v = session.query(Boy).first()
# print(v.hostname)
# print(v.girl)

# 使用relationship反向查询

# v = session.query(Girl).first()
# print(v.name)
# print(v.boys)

# session.close()

Flask-SQLAlchemy

flask和SQLAchemy的管理者，通过它吧他们连接起来。

flask多依赖于第三方软件，想使用就先安装:

安装：

pip3 install flask_sqlAchemy

重要参数：

"""
db = SQLAlchemy()
    - 包含配置
    - 包含ORM基类
    - 包含create_all
    - engine
    - 创建连接


"""

通过配置设置实现和Django一样，可以用命令makegirations来迁移数据库数据。

#!/usr/bin/env python
# -*- coding:utf-8 -*-
class BaseConfig(object):
    # SESSION_TYPE = ‘redis‘  # session类型为redis
    # SESSION_KEY_PREFIX = ‘session:‘  # 保存到session中的值的前缀
    # SESSION_PERMANENT = True  # 如果设置为False，则关闭浏览器session就失效。
    # SESSION_USE_SIGNER = False  # 是否对发送到浏览器上 session:cookie值进行加密
    SQLALCHEMY_DATABASE_URI = "mysql+pymysql://root:123@127.0.0.1:3306/flask01?charset=utf8"
    SQLALCHEMY_POOL_SIZE = 5
    SQLALCHEMY_POOL_TIMEOUT = 30
    SQLALCHEMY_POOL_RECYCLE = -1

    # 追踪对象的修改并且发送信号
    SQLALCHEMY_TRACK_MODIFICATIONS = False

class ProductionConfig(BaseConfig):
    pass

class DevelopmentConfig(BaseConfig):
    pass

class TestingConfig(BaseConfig):
    pass

操作区别

flask-migrate
#python3 manage.py db init 初始化：只执行一次

#python3 manage.py db migrate 等同于 makemigartions
#python3 manage.py db upgrade 等同于migrate

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