电梯直达

1楼 [收藏(0)] [报告]

发表于 2012-05-08 21:03 |只看该作者 |倒序浏览

在一个flask应用中，我需要用sqlalchemy动态的连接某几个库，而且有时会做新建数据库操作，每次请求都可能是不同的数据库。
每次请求都会reload模块db.py，这样做会不会影响服务器性能？还有其它用sqlalchemy的解决办法么？

main.py

from flask import Flask, render_template, request, session, g, redirect, url_for
from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker
from sqlalchemy.ext.declarative import declarative_base
app = Flask(__name__)
app.secret_key = '\x80\xeeW~\x17\x00@\xab\xd41\xe1]\x00I\x92 \xae\x8c\x00\xf6\xc4\xc1F\xdf'
@app.before_request
def before_request():
if not hasattr(g,'db'):
g.db = dict()
if session.has_key('login'):
db_str = 'mysql://root:qeephp@localhost:3306/%s?charset=utf8' % session['login']
engine = create_engine(db_str)
db_session = scoped_session(sessionmaker(autocommit=False,autoflush=False,bind=engine))
g.db[session['login']] = (engine, db_session)
else:
db_str = 'mysql://root:qeephp@localhost:3306/maindb?charset=utf8'
engine = create_engine(db_str)
db_session = scoped_session(sessionmaker(autocommit=False,autoflush=False,bind=engine))
g.db['default'] = (engine, db_session)
import db
db = reload(db)
@app.route('/')
def index():
return 'abc'
@app.route('/create')
def create():
import db
db = reload(db)
print db.engine
db.Base.metadata.drop_all(db.engine)
db.Base.metadata.create_all(db.engine)
if session.has_key('login'):
return 'login'
else:
return 'no login'
@app.route('/login')
def login():
session['login']='abcde'
return redirect(url_for('create'))
@app.route('/logout')
def logout():
session.pop('login', None)
return 'logout'
if __name__ == '__main__':
app.run(debug=True)

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db.py

#coding:utf-8
from flask import session, g
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, Text, ForeignKey, Table, func
from sqlalchemy.orm import relationship, backref
from sqlalchemy.orm.collections import attribute_mapped_collection
import hashlib,time
if session.has_key('login'):
engine, db_session = g.db[session['login']]
else:
engine, db_session = g.db['default']
Base = declarative_base()
print db_session
Base.query = db_session.query_property()
class User(Base):
__tablename__ = 'users' #职员表
id = Column(Integer, primary_key=True)
name = Column(String(50), unique=True)
created_at = Column(String(20), default = time.strftime("%Y-%m-%d %H:%M:%S", time.localtime()))
def __init__(self, name):
self.name = name

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2楼 [报告]

发表于 2012-05-10 07:41 |只看该作者

回复 1# hlsd665

先考虑把功能作对了再考虑速度吧

求助：web应用中，对于每次request，都reload一个模块，会不会影响性能？ [复制链接]