ruby-on-rails - 使用 declarative_authorization 保护敏感属性

Question

使用declarative_authorization按角色保护属性的好方法是什么？例如，用户可以编辑他的联系信息，但不能编辑他的角色。

我的第一个倾向是为不同的场景创建多个控制器动作。我很快意识到随着受保护属性数量的增加，这会变得多么笨拙。为用户角色执行此操作是一回事，但我可以想象多个受保护的属性。添加很多控制器操作和路由感觉不对。

我的第二个倾向是围绕特定敏感属性创建权限，然后使用 declarative_authorizations 提供的 View hepers 包装表单元素。但是，在我看来，模型和控制器方面有点模糊。建议会很棒。

请建议使用 declarative_authorizations 按角色保护属性的最佳方法。

score 5 · Accepted Answer

编辑 2011-05-22
从 3.1RC 开始，Rails 中现在有类似的东西https://github.com/rails/rails/blob/master/activerecord/test/cases/mass_assignment_security_test.rb所以我建议现在走这条路。

原始答案
我只需要将以前使用的内容移植到 Rails 3。我从未专门使用过声明式授权，但这非常简单明了，您应该能够适应它。

添加了 Rails 3 mass_assignment_authorizer，这让这一切变得非常简单。我以该链接教程为基础，并通过类继承并将属性分组为角色，使其更适合我的域模型。

在模型中

acts_as_accessible :admin => :all, :moderator => [:is_spam, :is_featured]
attr_accessible :title, :body # :admin, :moderator, and anyone else can set these

在控制器中

post.accessed_by(current_user.roles.collect(&:code)) # or however yours works
post.attributes = params[:post]

lib/active_record/acts_as_accessible.rb

# A way to have different attr_accessible attributes based on a Role
# @see ActsAsAccessible::ActMethods#acts_as_accessible
module ActiveRecord
  module ActsAsAccessible
    module ActMethods
      # In model
      # acts_as_accessible :admin => :all, :moderator => [:is_spam]
      # attr_accessible :title, :body
      #
      # In controller
      # post.accessed_by(current_user.roles.collect(&:code))
      # post.attributes = params[:post]
      #
      # Warning: This frequently wouldn't be the concern of the model where this is declared in,
      # but it is so much more useful to have it in there with the attr_accessible declaration.
      # OHWELL.
      #
      # @param [Hash] roles Hash of { :role => [:attr, :attr] }
      # @see acts_as_accessible_attributes
      def acts_as_accessible(*roles)
        roles_attributes_hash = Hash.new {|h,k| h[k] ||= [] }
        roles_attributes_hash = roles_attributes_hash.merge(roles.extract_options!).symbolize_keys

        if !self.respond_to? :acts_as_accessible_attributes
          attr_accessible
          write_inheritable_attribute :acts_as_accessible_attributes, roles_attributes_hash.symbolize_keys
          class_inheritable_reader    :acts_as_accessible_attributes

          # extend ClassMethods unless (class << self; included_modules; end).include?(ClassMethods)
          include InstanceMethods unless included_modules.include?(InstanceMethods)
        else # subclass
          new_acts_as_accessible_attributes = self.acts_as_accessible_attributes.dup
          roles_attributes_hash.each do |role,attrs|
            new_acts_as_accessible_attributes[role] += attrs
          end
          write_inheritable_attribute :acts_as_accessible_attributes, new_acts_as_accessible_attributes.symbolize_keys
        end
      end
    end

    module InstanceMethods
      # @param [Array, NilClass] roles Array of Roles or nil to reset
      # @return [Array, NilClass]
      def accessed_by(*roles)
        if roles.any?
          case roles.first
          when NilClass
            @accessed_by = nil
          when Array
            @accessed_by = roles.first.flatten.collect(&:to_sym)
          else
            @accessed_by = roles.flatten.flatten.collect(&:to_sym)
          end
        end
        @accessed_by
      end

      private
      # This is what really does the work in attr_accessible/attr_protected.
      # This override adds the acts_as_accessible_attributes for the current accessed_by roles.
      # @see http://asciicasts.com/episodes/237-dynamic-attr-accessible
      def mass_assignment_authorizer
        attrs = []
        if self.accessed_by
          self.accessed_by.each do |role|
            if self.acts_as_accessible_attributes.include? role
              if self.acts_as_accessible_attributes[role] == :all
                return self.class.protected_attributes
              else
                attrs += self.acts_as_accessible_attributes[role]
              end
            end
          end
        end
        super + attrs
      end
    end
  end
end

ActiveRecord::Base.send(:extend, ActiveRecord::ActsAsAccessible::ActMethods)

规范/lib/active_record/acts_as_accessible.rb

require 'spec_helper'

class TestActsAsAccessible
  include ActiveModel::MassAssignmentSecurity
  extend ActiveRecord::ActsAsAccessible::ActMethods
  attr_accessor :foo, :bar, :baz, :qux
  acts_as_accessible :dude => [:bar], :bra => [:baz, :qux], :admin => :all
  attr_accessible :foo
  def attributes=(values)
    sanitize_for_mass_assignment(values).each do |k, v|
      send("#{k}=", v)
    end
  end
end

describe TestActsAsAccessible do
  it "should still allow mass assignment to accessible attributes by default" do
    subject.attributes = {:foo => 'fooo'}
    subject.foo.should == 'fooo'
  end
  it "should not allow mass assignment to non-accessible attributes by default" do
    subject.attributes = {:bar => 'baaar'}
    subject.bar.should be_nil
  end
  it "should allow mass assignment to acts_as_accessible attributes when passed appropriate accessed_by" do
    subject.accessed_by :dude
    subject.attributes = {:bar => 'baaar'}
    subject.bar.should == 'baaar'
  end
  it "should allow mass assignment to multiple acts_as_accessible attributes when passed appropriate accessed_by" do
    subject.accessed_by :bra
    subject.attributes = {:baz => 'baaaz', :qux => 'quuux'}
    subject.baz.should == 'baaaz'
    subject.qux.should == 'quuux'
  end
  it "should allow multiple accessed_by to be specified" do
    subject.accessed_by :dude, :bra
    subject.attributes = {:bar => 'baaar', :baz => 'baaaz', :qux => 'quuux'}
    subject.bar.should == 'baaar'
    subject.baz.should == 'baaaz'
    subject.qux.should == 'quuux'
  end
  it "should allow :all access" do
    subject.accessed_by :admin
    subject.attributes = {:bar => 'baaar', :baz => 'baaaz', :qux => 'quuux'}
    subject.bar.should == 'baaar'
    subject.baz.should == 'baaaz'
    subject.qux.should == 'quuux'
  end
end

score 3 · Accepted Answer

对我来说，这个过滤问题应该在控制器级别应用。

您将希望在某处定义如何决定哪些属性对于给定用户是可写的。

# On the user model
class User < ActiveRecord::Base
  # ...

  # Return a list of symbols representing the accessible attributes
  def self.allowed_params(user)
    if user.admin?
      [:name, :email, :role]
    else
      [:name, email]
    end
  end
end

然后，在应用程序控制器中，您可以定义过滤参数的方法。

class ApplicationController < ActionController::Base
  # ...
  protected

  def restrict_params(param, model, user)
    params[param].reject! do |k,v|
      !model.allowed_params(user).include?(k)
    end
  end
  # ...
end

最后，在您的控制器操作中，您可以使用此过滤器：

class UserController < ActionController::Base
  # ...
  def update
    restrict_params(:user, User, @current_user)
    # and continue as normal
  end
  # ...
end

这个想法是，您可以在每个模型上定义 allowed_params ，并让每个模型的控制器使用相同的过滤器方法。您可以通过在应用程序控制器中使用一个吐出前置过滤器的方法来节省一些样板文件，如下所示：

def self.param_restrictions(param, model)
  before_filter do
    restrict_params(param, model, @current_user) if params[param]
  end
end

# in UserController
param_restrictions :user, User

这些示例旨在说明性而非确定性，我希望它们有助于实现这一点。

score 3 · Accepted Answer

我会使用scoped_attr_accessible，它看起来正是您正在寻找的。只有您需要在所有模型的请求开始时设置范围。

为此，请before_filter在 application_controller.rb 中使用 a：

before_filter do |controller|
  ScopedAttrAccessible.current_sanitizer_scope = controller.current_user.role
end

score 1 · Accepted Answer

我会避免基于模型中的用户访问的所有解决方案，因为它似乎有潜在危险。我会尝试这种方法：

class User < ActiveRecord::Base

  def update_attributes_as_user(values, user)
    values.each do |attribute, value|
      # Update the attribute if the user is allowed to
      @user.send("#{attribute}=", value) if user.modifiable_attributes.include?(attribute)
    end
    save
  end

  def modifiable_attributes
    admin? ? [:name, :email, :role] : [:name, :email]
  end
end

然后在您的控制器中更改您的更新操作：

@user.update_attributes(params[:user])

到

@user.update_attributes_as_user(params[:user], current_user)

score 0 · Accepted Answer

Rails 3.1+ 附带了一个用于此目的的 +assign_attributes+ 方法 - http://apidock.com/rails/ActiveRecord/AttributeAssignment/assign_attributes。

ruby-on-rails - 使用 declarative_authorization 保护敏感属性

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