sqlalchemy
优质
小牛编辑
130浏览
2023-12-01
问题
如何在web.py中使用sqlalchemy
方案
创建一个钩子并使用sqlalchemy的scoped session (http://www.sqlalchemy.org/docs/05/session.html#unitofwork_contextual)
import string
import random
import web
from sqlalchemy.orm import scoped_session, sessionmaker
from models import *
urls = (
"/", "add",
"/view", "view"
)
def load_sqla(handler):
web.ctx.orm = scoped_session(sessionmaker(bind=engine))
try:
return handler()
except web.HTTPError:
web.ctx.orm.commit()
raise
except:
web.ctx.orm.rollback()
raise
finally:
web.ctx.orm.commit()
app = web.application(urls, locals())
app.add_processor(load_sqla)
class add:
def GET(self):
web.header('Content-type', 'text/html')
fname = "".join(random.choice(string.letters) for i in range(4))
lname = "".join(random.choice(string.letters) for i in range(7))
u = User(name=fname
,fullname=fname + ' ' + lname
,password =542)
web.ctx.orm.add(u)
return "added:" + web.websafe(str(u)) \
+ "<br/>" \
+ '<a href="/view">view all</a>'
class view:
def GET(self):
web.header('Content-type', 'text/plain')
return "\n".join(map(str, web.ctx.orm.query(User).all()))
if __name__ == "__main__":
app.run()
###models.py
from sqlalchemy import create_engine
from sqlalchemy import Column, Integer, String
engine = create_engine('sqlite:///mydatabase.db', echo=True)
from sqlalchemy.ext.declarative import declarative_base
Base = declarative_base()
class User(Base):
__tablename__ = 'users'
id = Column(Integer, primary_key=True)
name = Column(String)
fullname = Column(String)
password = Column(String)
def __init__(self, name, fullname, password):
self.name = name
self.fullname = fullname
self.password = password
def __repr__(self):
return "<User('%s','%s', '%s')>" % (self.name, self.fullname, self.password)
users_table = User.__table__
metadata = Base.metadata
if __name__ == "__main__":
metadata.create_all(engine)
在跑程序之前,运行’python models.py’来初始化一次数据库.