python - ndb 模型、装饰器、嵌套函数

Question

我正在寻找有关我的应用程序的帮助。首先是示例代码(从大约 2k 行中删除...)，稍后我将尝试解释我要查找的内容:

from google.appengine.ext import ndb
import webapp2
import json

class User(ndb.Model):
  company_              = ndb.KeyProperty(repeated=True)

  @property
  def company(self):
    return {} if not self.company_ else self.company_

  @company.setter
  def company(self, value):
    if value:
      self.company_ = self.company_.expand(value) if self.company_ else [value]
    else:
      self.company_ = []
    self.put()

class Company(ndb.Model):
  administrator         = ndb.KeyProperty(kind=User, repeated=True)
  manager               = ndb.KeyProperty(kind=User, repeated=True)

  # FAKE decorator
  @staticmethod
  def administrator(handler):
    def check_requirements(self, *a, **kw):
      if True:
        return
      else:
        return handler(self, *a, **kw)
    return check_requirements

class BaseHandler(webapp2.RequestHandler):
  def jwrite(self, **kw):
    return self.response.out.write( json.dumps(kw) )

class require(BaseHandler):
  @staticmethod
  def login(handler):
    def check_requirements(self, *a, **kw):
      if not self.auth.get_user_by_session():
        self.redirect('/', abort=True)
      else:
        return handler(self, *a, **kw)
    return check_requirements

class ApiHandler(BaseHandler):
  @require.login
  def post(self, model, action, key=''):
    method = '_post_%s' % model
    try:
      getattr(self, method)(action, key)
    except Exception as error:
      return self.jwrite( error = error)

  def _post_company(self, action, key):

    if action == 'create':
      data = dict(self.request.POST)
      """ Company.create( data ) method:
          Populates Company instance with POST data.
          Assigns first user that created the company
            both administrator and manager roles.
      """
      key_ = Company.create( data ) 
      if key_:
        self.user.company = key_
      return

    elif action == 'delete':

      @Company.administrator
      def delete_all_user_companies(self):
        ndb.delete_multi( self.user.company )
        self.user.company = None
        return

      companies = ndb.get_multi( self.user.company )
      if self.user.key in map( lambda c: c.administrator, companies):
        delete_all_user_companies(self)

    elif action == 'update':

      @Company.manager
      def update_company(self, key):
        data = dict(self.request.POST)
        """ Company.update( key, data ) method:
            Populates Company instance with POST data
        """
        key_ = Company.update( key, data )
        if key_:
          return

      company = ndb.Key(Company, key).get()
      if self.user.key in company.manager.extend(company.administrator):
        update_company(self)

如您所见，我有用户和公司模型。用户可以拥有多个公司，公司可以拥有多个用户，这些用户可以是管理员或经理。您会注意到一些装饰器和嵌套函数 - 其中大多数都是假的 (; 但这就是我正在寻找的......

我正在使用 @require.login 装饰器进行基本的登录检查(我将其放在单独的类中，只是因为它在代码中看起来更干净 - @require.login 与 @BaseHandler.require_login )。有了它，我已经“保护”了 API 的 post 方法，现在我需要对角色进行额外的检查 - 管理员可以做一些经理不能做的事情。我需要在其他几个地方进行此检查，所以我认为这对于装饰器函数来说是一个好地方，但我不知道如何编写它们。我的第一个问题是:

1. 什么地方适合这个装饰器？我应该将它放在 Company 类中还是 ApiHandler 类中的某个位置？我的第一直觉是将它放在 Company 类中，但我不确定如何处理范围 - 我需要以某种方式在那里获取用户实例(self.user.company 列表)...

2. 接下来是ma​​nager装饰器。我如何将其写为装饰器:

     company = ndb.Key(Company, key).get()
     if self.user.key in company.manager.extend(company.administrator):
       update_company(self)
   

   并将其用作@Company.manager或@requre.manager，具体取决于我第一个问题的答案？

3. 管理员的另一个装饰器有点复杂 - 我必须检查用户是否是其所有公司的管理员，并删除他在的公司的管理员，同时保留他不在的公司的管理员:

     companies = ndb.get_multi( self.user.company )
     if self.user.key in map( lambda c: c.administrator, companies ):
       delete_all_user_companies(self)
   

   我什至不确定这个map()函数是否正确以及代码是否可以工作，还没有尝试过 - 现在它只是一个伪代码占位符......

4. 最后一个问题:我应该担心 POST 请求黑客攻击吗？根据上面的示例代码，是否有可能某些用户可以发出自定义 POST 请求并删除或更新不属于他的公司？

任何帮助、评论或见解将不胜感激(；谢谢!

Answer 1

我相信我已经解决了这个问题:

from google.appengine.ext import ndb
import webapp2
import json

class User(ndb.Model):
  company_              = ndb.KeyProperty(repeated=True)

  @property
  def company(self):
    return {} if not self.company_ else self.company_

  @company.setter
  def company(self, value):
    if value:
      # self.company_ = self.company_.expand(value) if self.company_ else [value]
      # Lists mutate when expanded. Code above was returning None
      self.company_ = self.company_ + [value] if self.company_ else [value]
    else:
      self.company_ = []
    self.put()

class Company(ndb.Model):
  administrator         = ndb.KeyProperty(kind=User, repeated=True)
  manager               = ndb.KeyProperty(kind=User, repeated=True)

class BaseHandler(webapp2.RequestHandler):
  def jwrite(self, **kw):
    return self.response.out.write( json.dumps(kw) )

class require(BaseHandler):
  @staticmethod
  def login(handler):
    def check_requirements(self, *a, **kw):
      if not self.auth.get_user_by_session():
        self.redirect('/', abort=True)
      else:
        return handler(self, *a, **kw)
    return check_requirements

class role(BaseHandler):
  @staticmethod
  def administrator(handler):
    def check_requirements(self, *a, **kw):
      # I didn't care much about optimizing queries
      # since this isn't frequent operation.
      # For more frequent calls, I'd consider projections.
      companies = ndb.get_multi( *a )
      # Next lines checks if current user is administrator 
      # for all companies passed to the function
      if not self.user.key in reduce(lambda x, y: x if x != y else y, map(lambda c: c.administrator, companies)):
        return self.jwrite( error = 'Permission denied. Administrator required.' )
      else:
        return handler(self, *a, **kw)
    return check_requirements

  @staticmethod
  def manager(handler):
    def check_requirements(self, *a, **kw):
      companies = ndb.get_multi( *a )
      # Next lines checks if current user is manager
      # or administrator (since admin has higher privileges) 
      # for all companies passed to the function
      if not self.user.key in reduce(lambda x, y: x if x != y else y, map(lambda c: c.manager + c.administrator, companies)):
        return self.jwrite( error = 'Permission denied. Manager or Administrator required.' )
      else:
        return handler(self, *a, **kw)
    return check_requirements

class ApiHandler(BaseHandler):
  @require.login
  def post(self, model, action, key=''):
    method = '_post_%s' % model
    try:
      getattr(self, method)(action, key)
    except Exception as error:
      return self.jwrite( error = error)

  def _post_company(self, action, key):

    if action == 'create':
      data = dict(self.request.POST)
      """ Company.create( data ) method:
          Populates Company instance with POST data.
          Assigns first user that created the company
            both administrator and manager roles.
      """
      key_ = Company.create( data ) 
      if key_:
        self.user.company = key_
      return

    elif action == 'delete':

      @role.administrator
      def delete_all_user_companies(self, *a):
        ndb.delete_multi( *a )
        self.user.company = None
        return

      delete_all_user_companies( self, self.user.company )

    elif action == 'update':

      @role.manager
      def update_company(self, *a ):
        data = dict(self.request.POST)
        """ Company.update( key, data ) method:
            Populates Company instance with POST data
        """
        key_ = Company.update( key, data )
        if key_:
          return

      update_company(self, ndb.Key(Company, key))

并回答我自己的问题:

1. 我在 Company 类内部命名时遇到了问题 - 属性管理员和装饰者具有相同的名称。因此，为了方便起见，我将装饰器移至 API 中，移至新类(角色)中。当我编写装饰器时，我意识到我可以将它们用于任何其他模型(带有经理和管理员字段)，所以我想这是一个很好的选择(;

2. 编写装饰器花了一些时间并尝试映射和减少数组，但我已经成功地完成了。我不确定是否将参数传递给装饰器。也许我应该在装饰器之外进行查询？或者将匹配的项目传递给处理函数？我得调查一下……

3. ...并删除他所在的位置，同时保留他不是管理员的位置 这就是我首先在装饰器内进行查询的原因。但仍不确定它是否聪明(;

4. 我仍然可以使用这个问题的答案。

希望这对某人有帮助......