Google App Engine - 安全Cookie

Question

我一直在寻找一种在Google App Engine中进行基于cookie的身份验证/会话的方法,因为我不喜欢基于memcache的会话的想法,我也不喜欢强迫用户创建谷歌帐户的想法使用网站.我偶然发现了某人的帖子,其中提到了Tornado框架中的一些已签名的cookie函数,它看起来就像我需要的那样.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,并且作为附带好处,用户ID将可用于请求处理程序数据存储工作等.该概念类似于ASP.NET中的表单身份验证.此代码来自Tornado框架的web.py模块.

根据文档字符串,它"标记和时间戳一个cookie,因此它不能伪造"和"返回给定的签名cookie,如果它验证,或无."

我试图在App Engine项目中使用它,但我不明白尝试让这些方法在请求处理程序的上下文中工作的细微差别.有人能告诉我正确的方法,而不会失去FriendFeed开发人员投入的功能吗？set_secure_cookie和get_secure_cookie部分是最重要的部分,但是能够使用其他方法也是很好的.

#!/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

UID = 1234 | 1234567890 | d32b9e9c67274fa062e2599fd659cc14

部分: 1.uid是
密钥
2 的名称.1234是清除值
3 的值
.1234567890是时间戳4. d32b9e9c67274fa062e2599fd659cc14是由值和时间戳创建的签名

Answer 1

Tornado从来没有打算与App Engine合作(它是"自己的服务器"贯穿始终).你为什么不接,而不是一些框架,是指为App Engine从字"走",是重量轻,花花公子,如tipfy？它使用自己的用户系统或任何App Engine自己的usersOpenIn,OAuth和Facebook 为您提供身份验证; 具有安全cookie或GAE数据存储的会话; 除此之外,所有这些都基于WSGI和Werkzeug的超轻量级"非框架"方法.有什么不喜欢的？!

Answer 2

如果有人感兴趣的话，这有效：

from google.appengine.ext import webapp

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


class ExtendedRequestHandler(webapp.RequestHandler):
    """Extends the Google App Engine webapp.RequestHandler."""
    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 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):
        """Hashes a string based on a pass-phrase."""
        hash = hmac.new("MySecretPhrase",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.request.cookies:
            return self.request.cookies[name]
        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))
        new_cookie = Cookie.BaseCookie()
        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
        for morsel in new_cookie.values():
            self.response.headers.add_header('Set-Cookie',morsel.OutputString(None))

    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

它可以这样使用：

class MyHandler(ExtendedRequestHandler):
    def get(self):
        self.set_cookie(name="MyCookie",value="NewValue",expires_days=10)
        self.set_secure_cookie(name="MySecureCookie",value="SecureValue",expires_days=10)

        value1 = self.get_cookie('MyCookie')
        value2 = self.get_secure_cookie('MySecureCookie')