Module | CanCan::ControllerAdditions |
In: |
lib/cancan/controller_additions.rb
|
Raises a CanCan::AccessDenied exception if the current_ability cannot perform the given action. This is usually called in a controller action or before filter to perform the authorization.
def show @article = Article.find(params[:id]) authorize! :read, @article end
A :message option can be passed to specify a different message.
authorize! :read, @article, :message => "Not authorized to read #{@article.name}"
You can also use I18n to customize the message. Action aliases defined in Ability work here.
en: unauthorized: manage: all: "Not authorized to %{action} %{subject}." user: "Not allowed to manage other user accounts." update: project: "Not allowed to update this project."
You can rescue from the exception in the controller to customize how unauthorized access is displayed to the user.
class ApplicationController < ActionController::Base rescue_from CanCan::AccessDenied do |exception| redirect_to root_url, :alert => exception.message end end
See the CanCan::AccessDenied exception for more details on working with the exception.
See the load_and_authorize_resource method to automatically add the authorize! behavior to the default RESTful actions.
Use in the controller or view to check the user‘s permission for a given action and object.
can? :destroy, @project
You can also pass the class instead of an instance (if you don‘t have one handy).
<% if can? :create, Project %> <%= link_to "New Project", new_project_path %> <% end %>
If it‘s a nested resource, you can pass the parent instance in a hash. This way it will check conditions which reach through that association.
<% if can? :create, @category => Project %> <%= link_to "New Project", new_project_path %> <% end %>
This simply calls "can?" on the current_ability. See Ability#can?.
Convenience method which works the same as "can?" but returns the opposite value.
cannot? :destroy, @project
Creates and returns the current user‘s ability and caches it. If you want to override how the Ability is defined then this is the place. Just define the method in the controller to change behavior.
def current_ability # instead of Ability.new(current_user) @current_ability ||= UserAbility.new(current_account) end
Notice it is important to cache the ability object so it is not recreated every time.