cookie
1、基本操作
Cookie是由服务器端生成，发送给User-Agent（一般是浏览器），浏览器会将Cookie的key/value保存到某个目录下的文本文件内，下次请求同一网站时就发送该Cookie给服务器（前提是浏览器设置为启用cookie）
在后台设置cookie：
class IndexHanlder(tornado.web.RequestHandler):
def get(self):
print(self.cookies) #获取http请求中携带的浏览器中的所有cookie
print(self.get_cookie("k1")) # 获取浏览器中的cooki
self.set_cookie("k1","v1") #为浏览器设置cookie
在前端（浏览器上使用JavaScript）：
document.cookie #获取浏览器中所有的cookie
document.cookie.split(";") #获取浏览器中具体某一个cookie，需要先分割，再操作
document.cookie = "k1=999" #设置cookie
由于Cookie保存在浏览器端，所以在浏览器端也可以使用JavaScript来操作Cookie：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<h1>123</h1>
</body>
<script>
/*设置cookie，指定秒数过期*/
function setCookieBySeconds(name,value,expires){
var current_date = new Date(); //获取当前时间
current_date.setSeconds(current_date.getSeconds() + expires);
document.cookie = name + "= "+ value +";expires=" + current_date.toUTCString();
}
/*设置cookie，指定天数过期*/
function setCookieByDays(name,value,expires){
var current_date = new Date(); //获取当前时间
current_date.setDate(current_date.getDate() + expires);
document.cookie = name + "= "+ value +";expires=" + current_date.toUTCString();
}
</script>
</html>
2、加密cookie（签名）
Cookie 很容易被恶意的客户端伪造。加入你想在 cookie 中保存当前登陆用户的 id 之类的信息，你需要对 cookie 作签名以防止伪造。Tornado 通过 set_secure_cookie 和 get_secure_cookie 方法直接支持了这种功能。 要使用这些方法，你需要在创建应用时提供一个密钥，名字为 cookie_secret。 你可以把它作为一个关键词参数传入应用的设置中：
def _create_signature_v1(secret, *parts): hash = hmac.new(utf8(secret), digestmod=hashlib.sha1) for part in parts: hash.update(utf8(part)) return utf8(hash.hexdigest()) # 加密 def _create_signature_v2(secret, s): hash = hmac.new(utf8(secret), digestmod=hashlib.sha256) hash.update(utf8(s)) return utf8(hash.hexdigest()) def create_signed_value(secret, name, value, version=None, clock=None, key_version=None): if version is None: version = DEFAULT_SIGNED_VALUE_VERSION if clock is None: clock = time.time timestamp = utf8(str(int(clock()))) value = base64.b64encode(utf8(value)) if version == 1: signature = _create_signature_v1(secret, name, value, timestamp) value = b"|".join([value, timestamp, signature]) return value elif version == 2: # The v2 format consists of a version number and a series of # length-prefixed fields "%d:%s", the last of which is a # signature, all separated by pipes. All numbers are in # decimal format with no leading zeros. The signature is an # HMAC-SHA256 of the whole string up to that point, including # the final pipe. # # The fields are: # - format version (i.e. 2; no length prefix) # - key version (integer, default is 0) # - timestamp (integer seconds since epoch) # - name (not encoded; assumed to be ~alphanumeric) # - value (base64-encoded) # - signature (hex-encoded; no length prefix) def format_field(s): return utf8("%d:" % len(s)) + utf8(s) to_sign = b"|".join([ b"2", format_field(str(key_version or 0)), format_field(timestamp), format_field(name), format_field(value), b'']) if isinstance(secret, dict): assert key_version is not None, 'Key version must be set when sign key dict is used' assert version >= 2, 'Version must be at least 2 for key version support' secret = secret[key_version] signature = _create_signature_v2(secret, to_sign) return to_sign + signature else: raise ValueError("Unsupported version %d" % version) # 解密 def _decode_signed_value_v1(secret, name, value, max_age_days, clock): parts = utf8(value).split(b"|") if len(parts) != 3: return None signature = _create_signature_v1(secret, name, parts[0], parts[1]) if not _time_independent_equals(parts[2], signature): gen_log.warning("Invalid cookie signature %r", value) return None timestamp = int(parts[1]) if timestamp < clock() - max_age_days * 86400: gen_log.warning("Expired cookie %r", value) return None if timestamp > clock() + 31 * 86400: # _cookie_signature does not hash a delimiter between the # parts of the cookie, so an attacker could transfer trailing # digits from the payload to the timestamp without altering the # signature. For backwards compatibility, sanity-check timestamp # here instead of modifying _cookie_signature. gen_log.warning("Cookie timestamp in future; possible tampering %r", value) return None if parts[1].startswith(b"0"): gen_log.warning("Tampered cookie %r", value) return None try: return base64.b64decode(parts[0]) except Exception: return None def _decode_fields_v2(value): def _consume_field(s): length, _, rest = s.partition(b':') n = int(length) field_value = rest[:n] # In python 3, indexing bytes returns small integers; we must # use a slice to get a byte string as in python 2. if rest[n:n + 1] != b'|': raise ValueError("malformed v2 signed value field") rest = rest[n + 1:] return field_value, rest rest = value[2:] # remove version number key_version, rest = _consume_field(rest) timestamp, rest = _consume_field(rest) name_field, rest = _consume_field(rest) value_field, passed_sig = _consume_field(rest) return int(key_version), timestamp, name_field, value_field, passed_sig def _decode_signed_value_v2(secret, name, value, max_age_days, clock): try: key_version, timestamp, name_field, value_field, passed_sig = _decode_fields_v2(value) except ValueError: return None signed_string = value[:-len(passed_sig)] if isinstance(secret, dict): try: secret = secret[key_version] except KeyError: return None expected_sig = _create_signature_v2(secret, signed_string) if not _time_independent_equals(passed_sig, expected_sig): return None if name_field != utf8(name): return None timestamp = int(timestamp) if timestamp < clock() - max_age_days * 86400: # The signature has expired. return None try: return base64.b64decode(value_field) except Exception: return None def get_signature_key_version(value): value = utf8(value) version = _get_version(value) if version < 2: return None try: key_version, _, _, _, _ = _decode_fields_v2(value) except ValueError: return None return key_version
五、Session（依赖于cookie）
由于cookie中需要保存客户的很多信息，而且如果信息很多的话，服务端与客户端交互的时候也浪费流量，所以我们需要用很少的一段字符串来保存很多的信息，这就是我们所要引进的session。
cookie 和session 的区别：
1、cookie数据存放在客户的浏览器上，session数据放在服务器上。
2、cookie不是很安全，别人可以分析存放在本地的COOKIE并进行COOKIE欺骗 考虑到安全应当使用session。
3、session会在一定时间内保存在服务器上。当访问增多，会比较占用你服务器的性能 考虑到减轻服务器性能方面，应当使用COOKIE。
4、单个cookie保存的数据不能超过4K，很多浏览器都限制一个站点最多保存20个cookie。
5、所以个人建议： 将登陆信息等重要信息存放为SESSION 其他信息如果需要保留，可以放在COOKIE中
（1）利用session实现用户验证
#!/usr/bin/env python
# -*- coding:utf-8 -*-
import tornado.web
import tornado.ioloop
import hashlib
import time
li = {}
class IndexHanlder(tornado.web.RequestHandler):
def get(self):
obj = hashlib.md5()
obj.update(bytes(str(time.time()),encoding="utf-8"))
random_str = obj.hexdigest()
li[random_str]={}
li[random_str]["k1"]=123
li[random_str]["k2"]=456
li[random_str]["is_login"]=True
self.set_cookie("qqqqqq",random_str)
self.write("成功设置cookie")
def post(self, *args, **kwargs):
pass
class ManagerHanlder(tornado.web.RequestHandler):
def get(self):
random_str = self.get_cookie("qqqqqq",None)
current_user_info = li.get(random_str,None)
if not current_user_info:
self.redirect("/index")
else:
if li[random_str]["is_login"]:
self.write("欢迎")
else:
self.redirect("/index")
def post(self, *args, **kwargs):
pass
settings={
"template_path":"tpl",
"static_path":"st",
"cookie_secret":"123"
}
class IndeHanlder(tornado.web.RequestHandler):
def get(self):
self.render("1.html")
application = tornado.web.Application([
(r"/index", IndexHanlder),
(r"/manager", ManagerHanlder),
],**settings)
if __name__ == "__main__":
application.listen(8888)
tornado.ioloop.IOLoop.instance().start()
（2）利用session验证用户精简版
#!/usr/bin/env/python
# -*- coding:utf-8 -*-
import tornado.web
container = {}
# container = {
# # "第一个人的随机字符串":{}，
# # "第一个人的随机字符串":{'k1': 111, 'parents': '你'}，
# }
class Session:
def __init__(self, handler):
self.handler = handler
self.random_str = None
def __genarate_random_str(self):
import hashlib
import time
obj = hashlib.md5()
obj.update(bytes(str(time.time()), encoding='utf-8'))
random_str = obj.hexdigest()
return random_str
def __setitem__(self, key, value):
# 在container中加入随机字符串
# 定义专属于自己的数据
# 在客户端中写入随机字符串
# 判断，请求的用户是否已有随机字符串
if not self.random_str:
random_str = self.handler.get_cookie('__kakaka__')
if not random_str:
random_str = self.__genarate_random_str()
container[random_str] = {}
else:
# 客户端有随机字符串
if random_str in container.keys():
pass
else:
random_str = self.__genarate_random_str()
container[random_str] = {}
self.random_str = random_str
container[self.random_str][key] = value
self.handler.set_cookie("__kakaka__", self.random_str)
def __getitem__(self, key):
# 获取客户端的随机字符串
# 从container中获取专属于我的数据
# 专属信息【key】
random_str = self.handler.get_cookie("__kakaka__")
if not random_str:
return None
# 客户端有随机字符串
user_info_dict = container.get(random_str,None)
if not user_info_dict:
return None
value = user_info_dict.get(key, None)
return value
class BaseHandler(tornado.web.RequestHandler):
def initialize(self):
self.session = Session(self)
class IndexHandler(BaseHandler):
def get(self):
if self.get_argument('u',None) in ['alex','eric']:
self.session['is_login'] = True
self.session['name'] =self.get_argument('u',None)
print(container)
else:
self.write('请你先登录')
class MangerHandler(BaseHandler):
def get(self):
val = self.session['is_login']
if val:
self.write(self.session['name'])
else:
self.write('登录失败')
class LoginHandler(BaseHandler):
def get(self,*args,**kwargs):
self.render('login.html',status="")
def post(self, *args, **kwargs):
user = self.get_argument('user',None)
pwd = self.get_argument('pwd',None)
code = self.get_argument('code',None)
check_code = self.session['CheckCode']
if code.upper() == check_code.upper():
self.write('验证码正确')
else:
self.render('login.html',status ='验证码错误')
class CheckCodeHandler(BaseHandler):
def get(self,*args,**kwargs):
import io
import check_code
mstream = io.BytesIO()
img, code = check_code.create_validate_code()
img.save(mstream,'GIF')
self.session['CheckCode']=code
self.write(mstream.getvalue())
class CsrfHandler(BaseHandler):
def get(self,*args,**kwargs):
self.render("csrf.html")
def post(self, *args, **kwargs):
self.write("hahahahaah")
settings = {
'template_path':'views',
'static_path':'static',
"xsrf_cookies":True
}
application = tornado.web.Application([
(r'/index',IndexHandler),
(r'/manger',MangerHandler),
(r'/login',LoginHandler),
(r'/check_code',CheckCodeHandler),
(r'/csrf',CsrfHandler),
],**settings)
if __name__ == "__main__":
application.listen(8888)
tornado.ioloop.IOLoop.instance().start()
