这里就不一一诉说Session和Cookie直接的关系了，下面以一张图来概括：
下面是一个简单的Tornaod自定义Session的例子，看完后你可能会明白为什么我们在Django里可以直接使用request.session来获取或者设置键值对的原因，在这个例子中包含了许多调用类里面的方法，例如__contains__ , __getitem__ , __setitem__ , __delitem__等：
版本1：
import tornado.ioloop
import tornado.web
import time,hashlib
from controllers.account import LoginHandler
from controllers.home import HomeHandler container = {}
# container = { '随机字符串或者cookie':{'uuuu':'root','k1':'v1'}, } class Session(object):
def __init__(self,handler):
self.handler = handler
self.random_str = None # 随机字符串，也有可能是cookie
self.client_random_str = self.handler.get_cookie('session_id')
print('哪里来的str',self.client_random_str)
if not self.client_random_str:
"""新用户，没有cookie的"""
# . 生成随机字符串当作session中的key,保存在大字典container中，用户每次访问都到里面找是否有该值
self.random_str = self.create_random_str()
container[self.random_str] = {} # 保存在大字典
else:
if self.client_random_str in container:
"""老用户，在container大字典里面了"""
self.random_str = self.client_random_str
print('老用户',container)
else:
"""非法用户，伪造的cookie"""
self.random_str = self.create_random_str()
container[self.random_str] = {} # . 生成cookie，必须调用LoginHandler才能使用set_cookie()
timeOut = time.time()
self.handler.set_cookie('session_id',self.random_str,expires=timeOut+) # . 写入缓存或数据库 ==> 后面用户自己调用session['uuuu'] = 'root' def create_random_str(self):
now = str(time.time())
m = hashlib.md5()
m.update(bytes(now,encoding='utf-8'))
return m.hexdigest() def __setitem__(self, key, value):
# print(key,value) # key 就是用户自己设置session['uuuu']='root'中的uuuu，value就是root
container[self.random_str][key] = value
# print('setitem',container) def __getitem__(self, item):
# print(item) # uuuu
# print('getitem',container)
return container[self.random_str].get(item) def __delitem__(self, key):
pass
def open(self):
pass
def cloes(self):
pass class Foo(object):
def initialize(self):
# print(self) # <__main__.LoginHandler object at 0x00000000038702E8>
self.session = Session(self)
super(Foo, self).initialize() # 执行RequestHandler中的initialize class HomeHandler(Foo,tornado.web.RequestHandler):
def get(self):
print('session',self.session)
user = self.session['uuuu'] # 调用Session类中的__getitem__方法, 获取value
print('user',user)
if not user:
self.write('不是合法登录')
else:
self.write(user) class LoginHandler(Foo,tornado.web.RequestHandler):
def get(self): # self.session['uuuu'] # 调用Session类中的__getitem__方法, 获取value
# del self.session['uuuu'] # 调用Session类中的__delitem__方法, 删除
self.session['uuuu'] = "root" # 调用Session类中的__setitem__方法，在session里面设置了uuuu
self.write("Hello, world")
print(container)
self.redirect('/home') application = tornado.web.Application([
# (r"/index", MainHandler),
(r"/login", LoginHandler),
(r"/home", HomeHandler),
]) if __name__ == "__main__":
application.listen()
tornado.ioloop.IOLoop.instance().start()
Version 1
版本2，可根据需要将session写入缓存或者数据库，下面以写入Cache为例：
import tornado.ioloop
import tornado.web
import time,hashlib
from controllers.account import LoginHandler
from controllers.home import HomeHandler container = {}
# container = { '随机字符串或者cookie':{'uuuu':'root','k1':'v1'}, } class Cache(object):
"""将session保存在内存"""
def __init__(self):
# self.container = {}
pass
def __contains__(self, item):
print('__contains__:',item)
return True
def initial(self,random_str):
container[random_str] = {}
def get(self,random_str,key):
return container[random_str].get(key) def set(self,random_str,key,value):
container[random_str]={}
container[random_str][key] = value
def delete(self,random_str,key):
del container[random_str][key]
def open(self):
pass
def close(self):
pass
def clear(self,random_str):
del container[random_str] class Memcache(object):
def __init__(self):
pass
def get(self,key):
pass
def set(self,key,value):
pass
def delete(self,key):
pass
def open(self):
pass
def close(self):
pass P = Cache # . 可以是Memcache，根据用户自己选择要写入缓存还是数据库... class Session(object):
def __init__(self,handler):
self.handler = handler
self.random_str = None # 随机字符串，也有可能是cookie
self.ppp = P()
# 去用户请求信息中获取session_id，如果没有，新用户
self.client_random_str = self.handler.get_cookie('session_id')
if not self.client_random_str:
"新用户"
self.random_str = self.create_random_str()
container[self.random_str] = {}
else:
if self.client_random_str in self.ppp:
"老用户"
self.random_str = self.client_random_str
else:
"非法用户"
self.random_str = self.create_random_str()
self.ppp.initial(self.random_str) # . 生成cookie，必须调用LoginHandler才能使用set_cookie()
timeOut = time.time()
self.handler.set_cookie('session_id',self.random_str,expires=timeOut+) # . 写入缓存或数据库 Cahce、Memcache ==> 后面用户自己调用session['uuuu'] = 'root' def create_random_str(self):
now = str(time.time())
m = hashlib.md5()
m.update(bytes(now,encoding='utf-8'))
return m.hexdigest() def __setitem__(self, key, value):
# print(key,value) # key 就是用户自己设置session['uuuu']='root'中的uuuu，value就是root
self.ppp.set(self.random_str, key, value)
print('',container) def __getitem__(self, item):
# print(item) # uuuu
# print('getitem',container)
print('',container)
return self.ppp.get(self.random_str,item) def __delitem__(self, key):
self.ppp.delete(self.random_str,key)
def open(self):
pass
def cloes(self):
pass class Foo(object):
def initialize(self):
# print(self) # <__main__.LoginHandler object at 0x00000000038702E8>
self.session = Session(self) # 传入Session的self就是调用者，谁调用Session谁就是self
super(Foo, self).initialize() # 执行RequestHandler中的initialize class HomeHandler(Foo,tornado.web.RequestHandler):
def get(self):
user = self.session['uuuu'] # 调用Session类中的__getitem__方法, 获取value
print('user',user)
if not user:
self.write('不是合法登录')
else:
self.write(user)
print('哈哈哈测试成功，删除啦')
del self.session['uuuu']
print(container) class LoginHandler(Foo,tornado.web.RequestHandler):
def get(self):
# self.session['uuuu'] # 调用Session类中的__getitem__方法, 获取value
# del self.session['uuuu'] # 调用Session类中的__delitem__方法, 删除
self.session['uuuu'] = "root" # 调用Session类中的__setitem__方法，在session里面设置了uuuu
self.write("Hello, world")
# print(container)
self.redirect('/home') application = tornado.web.Application([
# (r"/index", MainHandler),
(r"/login", LoginHandler),
(r"/home", HomeHandler),
]) if __name__ == "__main__":
application.listen()
tornado.ioloop.IOLoop.instance().start()
Version 2