python在工厂中的应用,将Python Flask应用配置为使用“ create_app”工厂并在模型类中使用数据库...
I'm having trouble getting my app to start when using a create_app() function. I'm new to building apps to this way and from all of my research it seems that my approach is different because I'm using my own database wrapper and not SQLAlchemy—which makes it easy because db.init_app(app) can be used.
My question is: I can't seem to access my database connection in /models/user.py... how do I fix this so I can use the db connection in that file?
This is my folder structure for the app, followed by those files listed:
/api
/common
database.py
/models
user.py
/resources
user.py
app.py
run.py
Here are my files
#
# File: run.py
#
from api.app import create_app
app = create_app(debug=True)
app.run(
host=app.config['APP_HOST'],
port=app.config['APP_PORT'],
debug=app.config['APP_DEBUG_FLASK'],
ssl_context=app.config['APP_SSL_CONTEXT']
)
#
# File: app.py
#
from logging.config import dictConfig
from flask import Flask
from flask_restful import Api
from api.config import LocalConfig, LiveConfig
from api.extensions import bcrypt, cors, jwt
from api.resources.user import *
from api.common.database import Database
def create_app(debug=True):
config = LocalConfig if debug else LiveConfig
# Create app
app = Flask(__name__)
# Set configuration variables
app.config.from_object(config)
app.secret_key = app.config['APP_SECRET_KEY']
app.url_map.strict_slashes = False
# Create api
api = Api(app, prefix='/api/v2')
# Initializing the logger
dictConfig(app.config['LOGGING'])
# Connect to mysql
db = Database(
host=app.config['MYSQL_HOST'],
db=app.config['MYSQL_DB'],
user=app.config['MYSQL_USER'],
passwd=app.config['MYSQL_PASS'],
)
register_decorators(app)
register_extensions(app)
register_endpoints(api)
return app
def register_extensions(app):
bcrypt.init_app(app)
jwt.init_app(app)
def register_endpoints(api):
api.add_resource(UserLogin, '/login')
#
# File: /resources/user.py
#
from flask_restful import Resource, reqparse
from api.models.user import *
class UserLogin(Resource):
def __init__(self):
self.reqparse = reqparse.RequestParser()
self.reqparse.add_argument('username', type=str, required=True,
help='Username is required.',
location='json')
self.reqparse.add_argument('password', type=str, default='', location='json')
def post(self):
args = self.reqparse.parse_args()
print(args['username'])
user = UserModel.get_by_username(args['username'])
return {'message': 'Wrong credentials'}
#
# File: /models/user.py
#
import datetime
import json
import logging
from api.common.database import Database
class UserModel:
@classmethod
def get_by_username(cls, username=None):
user = cls.db.getOne(
table='users',
fields=['user_id','data'],
where=('username = %s', [username])
)
if user:
user['data'] = json.loads(user['data'])
return user
#
# File: /common/database.py
#
import MySQLdb
class Database:
conn = None
cur = None
conf = None
def __init__(self, **kwargs):
self.conf = kwargs
self.conf['keep_alive'] = kwargs.get('keep_alive', False)
self.conf['charset'] = kwargs.get('charset', 'utf8')
self.conf['host'] = kwargs.get('host', 'localhost')
self.conf['port'] = kwargs.get('port', 3306)
self.conf['autocommit'] = kwargs.get('autocommit', False)
self.conf['ssl'] = kwargs.get('ssl', False)
self.connect()
def connect(self):
try:
if not self.conf['ssl']:
self.conn = MySQLdb.connect(db=self.conf['db'],
host=self.conf['host'],
port=self.conf['port'],
user=self.conf['user'],
passwd=self.conf['passwd'],
charset=self.conf['charset'])
else:
self.conn = MySQLdb.connect(db=self.conf['db'],
host=self.conf['host'],
port=self.conf['port'],
user=self.conf['user'],
passwd=self.conf['passwd'],
ssl=self.conf['ssl'],
charset=self.conf['charset'])
self.cur = self.conn.cursor(MySQLdb.cursors.DictCursor)
self.conn.autocommit(self.conf['autocommit'])
except:
print ('MySQL connection failed')
raise
def getOne(self, table=None, fields='', where=None, order=None, limit=(1,)):
### code that handles querying database directly ###
解决方案
I've started migrating toward using the form of the create_app pattern that Miguel Grinberg illustrations in part XI of his Flask Mega-Tutorial.
In your case, the reference to your db object locked in a local variable inside of create_app. The trick is to get it visible. Consider this scheme, which I use with SQLAlchemy, and which you would adapt to use your wrapper:
main.py
config.py
tests.py
app/
__init__.py
First, the default configuration which looks something like this (trimmed for brevity)
# config.py
...
class Config:
TESTING = False
SQLALCHEMY_DATABASE_URI = ...
...
The config will be used as a default by the factory.
# app/__init__.py
...
db = SQLAlchemy() # done here so that db is importable
migrate = Migrate()
def create_app(config_class=Config):
app = Flask(__name__)
app.config.from_object(config_class)
db.init_app(app)
migrate.init_app(app, db)
... register blueprints, configure logging etc.
return app
Note that from app import db works.
# main.py
from app import create_app
app = create_app()
And thenFLASK_APP=main.py venv/bin/flask run.
And for testing, a subclass of Config uses an in-memory database (and makes other tweaks to avoid hitting external services).
# tests.py
...
class TestConfig(Config):
TESTING = True
SQLALCHEMY_DATABASE_URI = 'sqlite://'
class ExampleTests(unittest.TestCase):
def setUp(self):
self.app = create_app(TestConfig)
# See Grinberg's tutorial for the other essential bits