can_self_do_it¶ ↑

• github.com/mbuceta/can_self_o_it

Description:¶ ↑

Generate a simple interface to works with users CRUD rights.

Features:¶ ↑

• Allows check permissions for CRUD actions can_create?, can_see?, can_edit? and can_delete?

• Allows check permissions for general actions responding to can_.+? regular expresion

• Add an interface for known users with a default implementation of the CRUD action permissions.

• Add an interface for unknown users with a default implementation of the CRUD action permissions.

• Allows add custom behaviors for especific objects instead of the default implementation

Synopsis:¶ ↑

Despite the fact that this gems hasn’t any dependency with others gems, it arises from the double permission checking in rails. We have to check action rights in controllers, and in the other hand we have to check rights to show actions in views.

This gem allows you to add the permission logic in one place and use it in both, views and controllers. Also, this gem add default behaviors for common cases. And overwrite the default behavior using custom implementations.

Basic usage in a Rails app:¶ ↑

Model:¶ ↑

class Post
...
end

# Represent an identified user of the application
class User
 acts_as_can_self_do_it(:as => CanSelfDoIt::Known)
 ...
end

View:¶ ↑

link_to('edit',   @post) if session_user.user.can_edit?(@post)
link_to('delete', @post) if session_user.user.can_delete?(@post)

Controller:¶ ↑

before_filter :check_post_edition_rights, :only => :edit
....
private

 def check_post_edition_rights
   render(:status => :unauthorized) unless session_user.can_edit?(@post)
 end

Complete usage example:¶ ↑

Application permissions management¶ ↑

Module for custom permissions for Guest (unknown user)

module GuestCustomPermissions
 # Ovewrite default CanSelfDoIt::Unknown implementation.
 # Guest only can see admin comments.
 # This method overrides
 # can_see? method for objects of Comment class.
 # i.e. this method is called when can_see?(comment) is
 # called and comment is a Comment
 def can_see_comment?(comment); comment.user.admin?; end
end

Module for custom permissions for User (known user)

module UserCustomPermissions
  # CanSelfDoIt::Known check this method for default implementation.
  def admin?; false;end

  # Ovewrite default CanSelfDoIt::Known implementation
  # Users can comment any post
  # This method overrides
  # can_create? method for objects of Comment class.
  # i.e. this method is called when can_create?(Comment, post)
  # The post param is the post in which the comment will be written
  def can_create_comment?(post); true; end
end

Module for custom permissions for Admin (admin like user)

module AdminCustomPermissions
  # CanSelfDoIt::Known check this method for default implementation.
  def admin?; true;end
end

Application classes¶ ↑

# Represent an unidentified user of the application
class Guest
  acts_as_can_self_do_it(:as => [CanSelfDoIt::Unknown, GuestCustomPermissions])
  ...
end

# Represent an identified user of the application
class User
  acts_as_can_self_do_it(:as => [CanSelfDoIt::Known, UserCustomPermissions])
  attr_accessor :blogs
  ...
end

# Represent the application admin
class Admin
  acts_as_can_self_do_it(:as => [CanSelfDoIt::Known, AdminCustomPermissions])
  attr_accessor :blogs
  ...
end

# A simple Blog + Post + Comment app
class Blog
  attr_accessor :user, :posts
  ...
end

class Post
  attr_accessor :blog, :comments, :user
  ...
end

class Comment
  attr_accessor :post, :user
  ...
end

CanSelfDoIt working¶ ↑

Working for an instance of Admin

an_admin.can_see?(admin_blog).should_be true
an_admin.can_see?(other_user_blog).should_be true
an_admin.can_edit?(admin_blog).should_be true
an_admin.can_edit?(other_user_blog).should_be true
an_admin.can_create?(Post, admin_blog).should_be true
an_admin.can_create?(Post, other_user_blog).should_be true

Working for an instance of User

an_user.can_see?(user_blog).should_be true
an_user.can_see?(other_user_blog).should_be true
an_user.can_edit?(user_blog).should_be true
an_user.can_edit?(other_user_blog).should_be false
an_user.can_create?(Post, user_blog).should_be true
an_user.can_create?(Post, other_user_blog).should_be false
# Custom
an_user.can_create?(Comment, user_post).should_be true
an_user.can_create?(Comment, other_user_post).should_be true

Working for an instance of Guest

a_guest.can_see?(user_blog).should_be true
a_guest.can_see?(user_post).should_be true
a_guest.can_edit?(user_blog).should_be false
a_guest.can_edit?(user_post).should_be false
a_guest.can_create?(Post, user_blog).should_be false
a_guest.can_create?(Comment, user_post).should_be false
# Custom
a_guest.can_see?(user_comment).should_be false
a_guest.can_see?(admin_comment).should_be true

Requirements:¶ ↑

This gems hasn’t dependencies

Install:¶ ↑

sudo gem install can_self_do_it

License:¶ ↑

(The MIT License)

Copyright © 2013 Juan Martin Buceta

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the ‘Software’), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED ‘AS IS’, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.