Flask Framework Beginner-05-Command Management Manager and Database Use

一、Manager使用

Flask引入了flask_script包,其中的ManagerClasses are used to manage and use related operator commands,在ManagerThere is an example of such a comment in the source code related to the classManager的典型用法,An inheritance is defined in the annotationCommand的Print类,这个类重写了Command中的run方法,实例化的manager对象使用add_commandMethod registration instantiates onePrint()类,主函数中manager调用run方法运行,最后Print()All methods in are executed.由此可见,Manager提供了一个Command类,只要继承了这个Command类,使用add_command()method to register the subclass,就可以使用manager的run()The method runs all functions in the subclass.（由于目前flask_script这个包已经被弃用,Therefore, the source code is no longer analyzed,作为了解即可,If you are interested, you can download the corresponding version to view）

    """ Controller class for handling a set of commands. Typical usage:: class Print(Command): def run(self): print "hello" app = Flask(__name__) manager = Manager(app) manager.add_command("print", Print()) if __name__ == "__main__": manager.run() On command line:: python manage.py print > hello :param app: Flask instance, or callable returning a Flask instance. :param with_default_commands: load commands **runserver** and **shell** by default. :param disable_argcomplete: disable automatic loading of argcomplete. """

使用1：基础应用

步骤一：下载 flask_script 包

pip install flask_script

步骤二：使用里面的 Manager Conduct commands to be managed and used

app = create_app()
# 绑定 app
manager = Manager(app=app)    
# 启动
 manager.run() 

步骤三：在终端使用命令

python app.py runserver
# 或者
python app.py runserver -h 0.0.0.0 -p 5001

使用2：添加自定义命令

步骤一：custom add command

@manager.command
def init():
    print('初始化')

步骤二：在终端运行命令

python app.py init

example:

settings.py

class DevelopmentConfig(Config):
    ENV = 'development'

class ProductConfig(Config):
    ENV = 'product'

apps下的__ init __.py

from flask import Flask

import settings

def create_app():
    app = Flask(__name__,template_folder='../templates',static_folder='../static')
    app.config.from_object(settings.DevelopmentConfig)
    return app

app.py

from apps import create_app

app = create_app()

manager = Manager(app=app)

# ._command[db] = MigrateCommand()
manager.add_command('db',MigrateCommand)

# custom add command
@manager.command
def init():
    print('初始化')

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

运行结果：

二、数据库的使用

这里介绍ORMThe object-relational mapping design model,O代表的是object对象,R代表的是Relational关系,M表示的是Mapping映射.ORM框架采用元数据来描述对象与关系映射的细节,You can map specific models to tables in the database one-to-one,The properties of the model object correspond to the fields of the database table,We can operate on database tables and fields by manipulating models and model objects.而Flask本身是没有实现ORM的,因此需要引入一个SQLToolkits and third-party libraries for object mapping tools are implementedORM,Flask-SQLAlchemy就是一种flaskThird-party libraries frequently referenced by database operations,But there is also a problem with using this 3rd party library,That is, when it is necessary to modify the database framework,Table initialization is generally useddb.create_all()这个方法,When the table needs to be modified,Will have to first go to the database to delete the table,Only then can the table of the new table structure be regenerated.为了解决这个问题,At this time, a third-party library was introducedflask-migrate,It can migrate data,并且集成到Flask-Script中,All migration operations are done via commands.为了导出数据库迁移命令,Flask-Migrate还提供了一个MigrateCommand类,可以附加到flask-script的manager对象上.

使用：

步骤一：下载相关包

# python 连接数据库 包
pip install pymysql
# Model object properties are mapped to the database
pip install flask-sqlalchemy
# 数据库迁移
pip install flask-migrate

步骤二：The connection path to the configuration database

 # mysql+pymysql: //user:[email protected]:port/databasename
 SQLALCHEMY_DATABASE_URI = 'mysql://root:[email protected]:3306/'

步骤三：创建一个ext包

# 步骤一：_init__.py中添加
db = SQLAlchemy()  ---->必须跟app联系
# 步骤二：apps-->__init__.py中添加
def create_app():
    ....
    db.init_app(app)
    return app
# 注：可使用[ python app.py db --help ]查看使用

步骤四：添加迁移命令到manager

app.py中添加：
manager = Manager(app=app)
migrate = Migrate(app=app,db=db)
manager.add_command('db',MigrateCommand)

运行：python app.py db 查看db的使用

步骤五：创建模型;models.py 相当于类

class User(db.Model):
    id = db.Column(db.Integer,primary_key = True,autoincrement = True)
    username =db.Column(db.String(15),nullable=False)
    password = db.Column(db.String(12),nullable=False)
    phone = db.Column(db.String(11),nullable=False)
    rdatetime = db.Column(db.DateTime,default=datetime.now)

步骤六：使用命令

a.在app.py中导入模型: from apps.user.models import User
b.在终端使用命令：python app.py db init     产生一个migrations文件夹
               python app.py db migrate  Generate a version file（versions下）
               python app.py db upgrade
c.导入相关驱动
    DataBase(If not, add the plugin yourself:file-->setting--->plugins)-->'+'

注：Remember to install the database and connection before this step,打开数据库后,运行相关命令
cmd中打开数据库,Check database table generation：

show databases;
use flaskdb01;
show tables;
desc user;

Example:

项目框架

settings.py

class Config:
    ENV = 'development'
    DEBUG = True
    # 连接数据库,格式：mysql+pymysql（驱动）: //user:[email protected]:port/databasename
    # SQLALCHEMY_DATABASE_URI = 'mysql+pymysql://root:[email protected]:3306/'
    SQLALCHEMY_DATABASE_URI = 'mysql://root:[email protected]:3306/flaskdb01'
    # 如果设置成True(默认情况),Flask-SQLAlchemyObject modifications will be tracked and signals will be sent,这需要消耗额外的内存
    SQLALCHEMY_TRACK_MODIFICATIONS = False
    # 调试设置为True
    SQLALCHEMY_ECHO = True

class DevelopmentConfig(Config):
    ENV = 'development'


class ProductConfig(Config):
    ENV = 'product'

ext下的__ init __.py

# 创建一个映射对象
from flask_sqlalchemy import SQLAlchemy
import pymysql
pymysql.install_as_MySQLdb()
db = SQLAlchemy()

apps.user.view.py

from flask import Blueprint, url_for

user_bp = Blueprint('user',__name__)

@user_bp.route('/')
def user_center():
    # 反向解析 Find the route by the function name
    print(url_for('user.register'))
    return '用户中心'


@user_bp.route('/register')
def register():

    return '用户注册'

apps下的__ init __.py

from flask import Flask

import settings
from apps.user.view import user_bp
from ext import db


def create_app():
    app = Flask(__name__,template_folder='../templates',static_folder='../static')
    app.config.from_object(settings.DevelopmentConfig)
    # 将db与app关联
    db.init_app(app)
    # 注册一个蓝图
    app.register_blueprint(blueprint=user_bp)

    return app

app.py

from flask_migrate import Migrate,MigrateCommand
from flask_script import Manager

from apps.user.models import User,UserInfo

from apps import create_app
from ext import db

app = create_app()

manager = Manager(app=app)
# 命令工具
migrate = Migrate(app=app,db=db)

# ._command[db] = MigrateCommand()
manager.add_command('db',MigrateCommand)

# custom add command
@manager.command
def init():
    print('初始化')

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

models.py

# ORM 类---》 表
# 类对象 ---》 表中的记录
from datetime import datetime

from ext import db

# create table user(id int primary key auto_increment,username varchar(20) not null,....
class User(db.Model):
    # db.Column(类型,约束) 映射表中的列
    ''' 类型： db.Integer int db.String varchar(15) db.DateTime datatime '''
    id = db.Column(db.Integer,primary_key = True,autoincrement = True)
    username =db.Column(db.String(15),nullable=False)
    passwords = db.Column(db.String(12),nullable=False)
    phone = db.Column(db.String(11),nullable=False)
    email = db.Column(db.String(20))
    rdatetime = db.Column(db.DateTime,default=datetime.now)



    def __str__(self):
        return self.username

class UserInfo(db.Model):
    id = db.Column(db.Integer,primary_key=True,autoincrement=True)
    realname = db.Column(db.String(20))
    gender = db.Column(db.Boolean,default=False)

    def __str__(self):
        return self.realname

终端运行db的init命令,将会产生一个migrations文件夹

python app.py db init

终端运行db的migrate命令,A version file will be generated（versions下)

python app.py db migrate

终端运行db的upgrade命令,The data structure will be updated

python app.py db upgrade

补充：

|----apps
|----ext
|----migrations
    |----versions  版本文件夹
        |----c1ad2ea8b56f_.py    --->python app.py migrate  生成版本信息
        |----90c023e77fdb_.py
                                 ---> python app.py upgrade  升级版本
                                 --->python app.py downgrade  降级版本

三、简单应用

项目框架

settings.py

class Config:
    Debug = True
    SQLALCHEMY_DATABASE_URI = 'mysql://root:[email protected]:3306/flaskdb02'
    SQLALCHEMY_TRACK_MODIFICATIONS = False
    SQLALCHEMY_ECHO = True

class DevelopmentConfig(Config):
    ENV = 'development'
    Debug = True

class ProductionConfig(Config):
    ENV = 'production'
    Debug = True

ext下的 __ init __.py

from flask_sqlalchemy import SQLAlchemy
import pymysql
pymysql.install_as_MySQLdb()
# 实例化一个SQLAlchemy对象db
db = SQLAlchemy()

apps下的 __ init __.py

from flask import Flask

import settings
from apps.user.view import user_bp
from exts import db


def create_app():
    app = Flask(__name__,template_folder='../templates',static_folder='../static')
    app.config.from_object(settings.DevelopmentConfig)
    # 初始化配置db
    db.init_app(app = app)
    # 绑定view中的蓝图
    app.register_blueprint(user_bp)

    return app

app.py

from flask_migrate import Migrate,MigrateCommand
from flask_script import Manager
from  apps.user.models import User

from apps import create_app
from exts import db

app = create_app()
manager = Manager(app = app)

# 
migrate = Migrate(app=app,db=db)
# Added data migration command._command中
manager.add_command('db', MigrateCommand)


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

models.py

from datetime import datetime

from exts import db

# Create a model corresponding to the tables and fields in the database
class User(db.Model):
    id = db.Column(db.Integer,primary_key=True,autoincrement=True)
    username = db.Column(db.String(15),nullable=False)
    password = db.Column(db.String(12),nullable=False)
    phone = db.Column(db.String(11),unique=True)
    rdatetime = db.Column(db.DateTime,default=datetime.now())

    def __str__(self):
        return self.username

view.py

from flask import Blueprint, request, render_template

from apps.user.models import User
from exts import db

user_bp = Blueprint('user',__name__)

@user_bp.route('/register',methods=['GET','POST'])
def register():
    if request.method =='POST':
        username = request.form.get('username')
        password = request.form.get('password')
        repassword = request.form.get('repassword')
        phone = request.form.get('phone')
        if password == repassword:
            # 创建对象
            user = User()
            # 对象赋值
            user.username = username
            user.password = password
            user.phone = phone
            # Add the object to the cache
            db.session.add(user)
            db.session.commit()
            return '用户注册成功！'

    return render_template('user/register.html')

终端运行

python app.py db init

python app.py db migrate

python app.py db upgrade

终端运行

python app.py runserver

访问 http://127.0.0.1:5000/register

查看数据库：