Initialize the flask environment

pip install pipenv 
mkdir flasky
pipenv shell
pipenv install flask
# Install plug-ins
pipenv install flask-sqlalchemy flask-migrate flask-wtf flask-mail pymysql
mkdir app

Create an. env file. The. env file will be loaded when using pipenv

# .env
FLASK_APP=run.py
FLASK_DEBUG = 1

app initialization

Create a new initialization file and use the factory function to create an app so that when you write unittest later, you can dynamically pass in different configurations to generate an app instance.

# app/__init__.py
from flask import Flask 
from config import config
from flask_sqlalchemy import SQLAlchemy
from flask_mail  import Mail

# Database connection
db = SQLAlchemy()
# Send mail
mail = Mail()

def create_app(config_name):
    app = Flask(__name__)
    app.config.from_object(config[config_name])
    # Initialize various plug-ins
    config[config_name].init_app(app)
    db.init_app(app)
    mail.init_app(app)

    return app

Profile initialization

New config.py

# config.py
# coding: utf-8
import os 

class Config(object):
    SECRET_KEY = os.getenv('SECRET')
    MAIL_SERVER = os.getenv('MAIL_SERVER')
    MAIL_PORT = os.getenv("MAIL_PORT")
    MAIL_USE_TLS = os.getenv("MAIL_USE_TLS")
    MAIL_USERNAME = os.getenv("MAIL_USERNAME")
    MAIL_PASSWD = os.getenv("MAIL_PASSWD")
    SQLALCHEMY_TRACK_MODIFICATIONS = False

    def init_app(self):
        pass
        
class DevConfig(Config):
    DEBUG = True
    SQLALCHEMY_DATABASE_URI = os.getenv("DEV_SQLALCHEMY_DATABASE_URI") or "mysql+pymysql://root:qwe123@127.0.0.1/flasky"

class TestingConfig(Config):
    Testing = True
    SQLALCHEMY_DATABASE_URI = os.getenv("TEST_SQLALCHEMY_DATABASE_URI") or "mysql+pymysql://root:qwe123@127.0.0.1/flasky"

class ProdConfig(Config):
    SQLALCHEMY_DATABASE_URI = os.getenv("SQLALCHEMY_DATABASE_URI") or "mysql+pymysql://root:qwe123@127.0.0.1/flasky"


config = {
    "dev":DevConfig,
    "test":TestingConfig,
    "prod":ProdConfig,
    "default":DevConfig
}

Add content to. env file

# .env
...
SECRET_KEY = 81785a8c-1f9a-4cfb-bc9d-90a8374bbc15 
MAIL_SERVER = xxx
MAIL_PORT = xxx
MAIL_USE_TLS = xx
MAIL_USERNAME = tester
MAIL_PASSWD = qwe123
DEV_SQLALCHEMY_DATABASE_URI= xxx
TEST_SQLALCHEMY_DATABASE_URI=xxx
SQLALCHEMY_DATABASE_URI = xxx

Initialize log

When the application is running, the best practice is not to directly output the error information to the page for users to see, which is neither professional nor safe. The best practice is to direct the user to 500 pages when the application has errors, and then log the errors for the development to investigate.

# app/__init__.py
from logging.handlers import SMTPHandler,RotatingFileHandler

def create_app(config_name):
    ...
    if not app.debug:
        
        # Record to file
        if not os.path.exists('logs'):
                    os.mkdir('logs')
        file_handler = RotatingFileHandler('logs/flasky.log',maxBytes=10240,backupCount=10)
        file_handler.setFormatter(logging.Formatter(
            '%(asctime)s %(levelname)s: %(message)s [in %(pathname)s:%(lineno)d]'))
        file_handler.setLevel(logging.INFO)
        app.logger.addHandler(file_handler)
        app.logger.info('app start.')

        # Send mail without setting
        auth = None
        if app.config['MAIL_USERNAME'] or app.config['MAIL_PASSWD']:
            auth = (app.config['MAIL_USERNAME'],app.config['MAIL_PASSWD'])
        secure = None
        if app.config['MAIL_USE_SSL']:
            secure = ()
        
        mail_handler = SMTPHandler(
                mailhost=app.config['MAIL_SERVER'],
                fromaddr=app.config['MAIL_USERNAME'],
                toaddrs=app.config['ADMINS'],
                subject="flasky Error",
                credentials=auth,secure=secure)
        mail_handler.setLevel(logging.ERROR)
        app.logger.addHandler(mail_handler)

Blueprint / plug and play view

Functional modules are used to divide blueprints, and plug and play views are used to separate routing and logical processing. Easy code management.
Create a new index folder and add the file "init". Py "

# index/__init__.py
from flask import Blueprint
index_bp = Blueprint("index",__name__)
from . import views,routes

# index/views.py
from flask.views import MethodView 
from flask import render_template
class Index(MethodView):
    def get(self):
        return render_template("index.html")

# index/routes.py
from index import index_bp
from index.views import Index

index_bp.add_url_rule('/',view_func=Index.as_view('index'))

# When you need URL for, you can use the name index.index
# url_for('index.index') index can be compared to the name of this function

This completes the basic setup of a blueprint. Next, add the blueprint to the app instance

# app/__init__.py
def create_app(config_name):
    ...
    from app.index import index_bp 
    app.register_blueprint(index_bp)
    ...
    return app

test

Test whether the initialization function is normal

pipenv shell
flask run 

open http://localhost : 5000 check for errors

Code address: https://github.com/TheFifthMa...

Reference resources

Recommended reading: oreally. Flask. Web. Development. 2nd. Edition