工厂方法

#coding=utf-8
#app.py
from flask import Flask
from flask import render_template
from book.book import book_bp
from configs import config


def create_app(config_name):

    app = Flask(__name__)

    #basic config
    app.config.from_object(config[config_name])

    #blueprint
    app.register_blueprint(book_bp)

    #error_handler
    handler_errors(app)

    return app

def handler_errors(app):
    @app.errorhandler(404)
    def page_not_found(error):
        return render_template("404.html")


#run.py
#coding=utf-8

from app import create_app

app = create_app('default')

if __name__ == "__main__":
    app.run(debug=True)