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我一直在寻找一种方法来在Google App Engine中执行基于cookie的身份验证/会话，因为我不喜欢基于memcache的会话的想法，而且我也不喜欢这个想法强制用户创建Google帐户只是为了使用网站。我偶然发现某人的posting提到了Tornado框架中的一些签名cookie功能，它看起来像我所需要的。我想到的是将用户的ID存储在防篡改cookie中，并且可能使用装饰器来请求处理程序来测试用户的身份验证状态，并且作为副作用，用户ID将可用于请求处理程序数据存储工作等。这个概念与ASP.NET中的表单身份验证类似。这段代码来自Tornado框架的web.py模块。Google App Engine - 安全Cookie
根据文档字符串，它“签名和时间戳一个cookie，以便它不能伪造”和 “返回给定的签名cookie，如果它有效，或无。”
我试过在App Engine项目中使用它，但我不明白试图让这些方法在请求处理程序的上下文中工作的细微差别。有人可以告诉我正确的方式来做到这一点，而不会丢失FriendFeed开发者投入的功能吗？ set_secure_cookie和get_secure_cookie部分是最重要的部分，但能够使用其他方法也会很好。
#!/usr/bin/env python
import Cookie
import base64
import time
import hashlib
import hmac
import datetime
import re
import calendar
import email.utils
import logging
def _utf8(s):
if isinstance(s, unicode):
return s.encode("utf-8")
assert isinstance(s, str)
return s
def _unicode(s):
if isinstance(s, str):
try:
return s.decode("utf-8")
except UnicodeDecodeError:
raise HTTPError(400, "Non-utf8 argument")
assert isinstance(s, unicode)
return s
def _time_independent_equals(a, b):
if len(a) != len(b):
return False
result = 0
for x, y in zip(a, b):
result |= ord(x)^ord(y)
return result == 0
def cookies(self):
"""A dictionary of Cookie.Morsel objects."""
if not hasattr(self,"_cookies"):
self._cookies = Cookie.BaseCookie()
if "Cookie" in self.request.headers:
try:
self._cookies.load(self.request.headers["Cookie"])
except:
self.clear_all_cookies()
return self._cookies
def _cookie_signature(self,*parts):
self.require_setting("cookie_secret","secure cookies")
hash = hmac.new(self.application.settings["cookie_secret"],
digestmod=hashlib.sha1)
for part in parts:hash.update(part)
return hash.hexdigest()
def get_cookie(self,name,default=None):
"""Gets the value of the cookie with the given name,else default."""
if name in self.cookies:
return self.cookies[name].value
return default
def set_cookie(self,name,value,domain=None,expires=None,path="/",
expires_days=None):
"""Sets the given cookie name/value with the given options."""
name = _utf8(name)
value = _utf8(value)
if re.search(r"[\x00-\x20]",name + value):
# Don't let us accidentally inject bad stuff
raise ValueError("Invalid cookie %r:%r" % (name,value))
if not hasattr(self,"_new_cookies"):
self._new_cookies = []
new_cookie = Cookie.BaseCookie()
self._new_cookies.append(new_cookie)
new_cookie[name] = value
if domain:
new_cookie[name]["domain"] = domain
if expires_days is not None and not expires:
expires = datetime.datetime.utcnow() + datetime.timedelta(
days=expires_days)
if expires:
timestamp = calendar.timegm(expires.utctimetuple())
new_cookie[name]["expires"] = email.utils.formatdate(
timestamp,localtime=False,usegmt=True)
if path:
new_cookie[name]["path"] = path
def clear_cookie(self,name,path="/",domain=None):
"""Deletes the cookie with the given name."""
expires = datetime.datetime.utcnow() - datetime.timedelta(days=365)
self.set_cookie(name,value="",path=path,expires=expires,
domain=domain)
def clear_all_cookies(self):
"""Deletes all the cookies the user sent with this request."""
for name in self.cookies.iterkeys():
self.clear_cookie(name)
def set_secure_cookie(self,name,value,expires_days=30,**kwargs):
"""Signs and timestamps a cookie so it cannot be forged"""
timestamp = str(int(time.time()))
value = base64.b64encode(value)
signature = self._cookie_signature(name,value,timestamp)
value = "|".join([value,timestamp,signature])
self.set_cookie(name,value,expires_days=expires_days,**kwargs)
def get_secure_cookie(self,name,include_name=True,value=None):
"""Returns the given signed cookie if it validates,or None"""
if value is None:value = self.get_cookie(name)
if not value:return None
parts = value.split("|")
if len(parts) != 3:return None
if include_name:
signature = self._cookie_signature(name,parts[0],parts[1])
else:
signature = self._cookie_signature(parts[0],parts[1])
if not _time_independent_equals(parts[2],signature):
logging.warning("Invalid cookie signature %r",value)
return None
timestamp = int(parts[1])
if timestamp < time.time() - 31 * 86400:
logging.warning("Expired cookie %r",value)
return None
try:
return base64.b64decode(parts[0])
except:
return None
的uid = 1234 | 1234567890个| d32b9e9c67274fa062e2599fd659cc14
配件：
1. UID是其中的关键
2. 1234名是明确
3 1234567890你的价值是时间戳
4. d32b9e9c67274fa062e2599fd659cc14是由数值和时间戳制成的签名
我没打算用旋风App Engine的，我只是想设置和获取以他们的方式签署cookie。我看了一下tipfy/werkzeug安全cookie代码，我认为他们在Tornado做的更优雅。 – tponthieux 2010-03-28 08:52:30