如何定义cancan中的实例能力而不定义类能力?

How do I define instance abilities in cancan without defining class abilities?

如何定义cancan中的实例能力而不定义类能力?

I want to allow the :manage action for particular Course instances, not the Course class.

我想允许:针对特定的课程实例管理操作，而不是课程类。

# ability.rb
can :manage, Course do |course|
  # Check if the user is a helper for this course
  CourseRole.get_role(user, course) == "helper"
end

This works fine for instance variables:

这适用于实例变量:

# some_view.rb
can? :manage, @course # checks the instance to see if :manage is allowed

But if I do this:

但如果我这样做:

# some_view.rb
can? :manage, Course 

it always returns true, which is bad.

它总是返回true，这很糟糕。

Some context:

一些背景:

class User < ActiveRecord::Base
  has_many :course_roles
  has_many :courses, :through => :course_roles
  ...
class CourseRoles < ActiveRecord::Base
  belongs_to :user
  belongs_to :course
  ...
class Courses < ActiveRecord::Base
  has_many :course_roles
  has_many :users, :through => :course_roles

1 个解决方案

#1

instead of can? :manage, Course, you can use can? :manage, Course.new and be sure that new course objects fail the block you passed in ability.rb

代替可以吗?:管理，当然，你可以用can吗?:管理课程。新并确保新课程对象失败了您在ability.rb中传递的块