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"",
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""):
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()