12 Commits
0.2.0 ... 0.2.1

11 changed files with 436 additions and 159 deletions

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@@ -1,3 +1,11 @@
0.2.1 (Nov 26, 2009)
* many internal refactorings - see issues #11 and #12
* adding "cannot" method to define which abilities cannot be done - see issue #7
* support custom objects (usually symbols) in can definition - see issue #8
0.2.0 (Nov 17, 2009) 0.2.0 (Nov 17, 2009)
* fix behavior of load_and_authorize_resource for namespaced controllers - see issue #3 * fix behavior of load_and_authorize_resource for namespaced controllers - see issue #3

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@@ -4,6 +4,7 @@ This is a simple authorization solution for Ruby on Rails to restrict what a giv
This assumes you already have authentication (such as Authlogic[http://github.com/binarylogic/authlogic]) which provides a current_user model. This assumes you already have authentication (such as Authlogic[http://github.com/binarylogic/authlogic]) which provides a current_user model.
See the RDocs[http://rdoc.info/projects/ryanb/cancan] and Wiki[http://wiki.github.com/ryanb/cancan] for additional documentation.
== Installation == Installation
@@ -111,16 +112,10 @@ You can also pass :manage as the action which will match any action. In this cas
action != :destroy action != :destroy
end end
Finally, you can use the "alias_action" method to alias one or more actions into one. Finally, the "cannot" method works similar to "can" but defines which abilities cannot be done.
alias_action :update, :destroy, :to => :modify can :read, :all
can :modify, Comment cannot :read, Product
The following aliases are added by default for conveniently mapping common controller actions.
alias_action :index, :show, :to => :read
alias_action :new, :to => :create
alias_action :edit, :to => :update
== Checking Abilities == Checking Abilities
@@ -140,21 +135,19 @@ The "cannot?" method is for convenience and performs the opposite check of "can?
cannot? :destroy, @project cannot? :destroy, @project
== Custom Actions == Aliasing Actions
You can have fine grained control over abilities by coming up with new actions. For example, if only pro users are allowed to upload a picture for their product, you could add the following restrictions. You can use the "alias_action" method to alias one or more actions into one.
# ability.rb alias_action :update, :destroy, :to => :modify
can :upload_picture, Project if user.pro? can :modify, Comment
can? :update, Comment # => true
# projects/_form.html.erb The following aliases are added by default for conveniently mapping common controller actions.
<%= f.file_field :picture if can? :upload_picture, @project %>
# projects_controller.rb alias_action :index, :show, :to => :read
def update alias_action :new, :to => :create
unauthorized! if params[:project][:upload_picture] && cannot?(:upload_picture, @project) alias_action :edit, :to => :update
# ...
end
== Assumptions & Configuring == Assumptions & Configuring
@@ -173,48 +166,16 @@ You can override these by overriding the "current_ability" method in your Applic
That's it! That's it!
== Permissions in Database
Perhaps a non-coder needs the ability to modify the user abilities, or you want to change them without having to re-deploy the application. In that case it may be best to store the permission logic in a separate model, let's call it Permission. It is easy to use the database records when defining abilities.
For example, let's assume that each user has_many :permissions, and each permission has "action", "object_type" and "object_id" columns. The last of which is optional.
class Ability
include CanCan::Ability
def initialize(user)
can :manage, :all do |action, object_class, object|
user.permissions.find_all_by_action(action).any? do |permission|
permission.object_type == object_class.to_s &&
(object.nil? || permission.object_id.nil? || permission.object_id == object.id)
end
end
end
end
An alternatie approach is to define a separate "can" ability for each permission.
def initialize(user)
user.permissions.each do |permission|
can permission.action, permission.object_type.constantize do |object|
object.nil? || permission.object_id.nil? || permission.object_id == object.id
end
end
end
The actual details will depend largely on your application requirements, but hopefully you can see how it's possible to define permissions in the database and use them with CanCan.
== Testing Abilities == Testing Abilities
It is very easy to test the Ability model since you can call "can?" directly on it as you would in the view or controller. It is very easy to test the Ability model since you can call "can?" directly on it as you would in the view or controller.
def test "user can only destroy projects which he owns" def test "user can only destroy projects which he owns"
user = User.new user = User.new
ability = Ability.new(user) ability = Ability.new(user)
assert ability.can?(:destroy, Project.new(:user => user)) assert ability.can?(:destroy, Project.new(:user => user))
assert ability.cannot?(:destroy, Project.new) assert ability.cannot?(:destroy, Project.new)
end end
== Special Thanks == Special Thanks

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@@ -4,8 +4,8 @@ Gem::Specification.new do |s|
s.description = "Simple authorization solution for Rails which is completely decoupled from the user's roles. All permissions are stored in a single location for convenience." s.description = "Simple authorization solution for Rails which is completely decoupled from the user's roles. All permissions are stored in a single location for convenience."
s.homepage = "http://github.com/ryanb/cancan" s.homepage = "http://github.com/ryanb/cancan"
s.version = "0.2.0" s.version = "0.2.1"
s.date = "2009-11-17" s.date = "2009-11-26"
s.authors = ["Ryan Bates"] s.authors = ["Ryan Bates"]
s.email = "ryan@railscasts.com" s.email = "ryan@railscasts.com"

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@@ -1,6 +1,9 @@
module CanCan module CanCan
# This error is raised when a user isn't allowed to access a given
# controller action. See ControllerAdditions#unauthorized! for details.
class AccessDenied < StandardError; end class AccessDenied < StandardError; end
end end
require File.dirname(__FILE__) + '/cancan/ability' require File.dirname(__FILE__) + '/cancan/ability'
require File.dirname(__FILE__) + '/cancan/resource_authorization'
require File.dirname(__FILE__) + '/cancan/controller_additions' require File.dirname(__FILE__) + '/cancan/controller_additions'

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@@ -1,49 +1,168 @@
module CanCan module CanCan
# This module is designed to be included into an Ability class. This will
# provide the "can" methods for defining and checking abilities.
#
# class Ability
# include CanCan::Ability
#
# def initialize(user)
# if user.admin?
# can :manage, :all
# else
# can :read, :all
# end
# end
# end
#
module Ability module Ability
attr_accessor :user attr_accessor :user
def can?(original_action, target) # TODO this could use some refactoring # Use to check the user's permission for a given action and object.
(@can_history || []).reverse.each do |can_action, can_target, can_block| #
can_actions = [can_action].flatten # can? :destroy, @project
can_targets = [can_target].flatten #
possible_actions_for(original_action).each do |action| # You can also pass the class instead of an instance (if you don't have one handy).
if (can_actions.include?(:manage) || can_actions.include?(action)) && (can_targets.include?(:all) || can_targets.include?(target) || can_targets.any? { |c| target.kind_of?(c) }) #
if can_block.nil? # can? :create, Project
return true #
else # Not only can you use the can? method in the controller and view (see ControllerAdditions),
block_args = [] # but you can also call it directly on an ability instance.
block_args << action if can_actions.include?(:manage) #
block_args << (target.class == Class ? target : target.class) if can_targets.include?(:all) # ability.can? :destroy, @project
block_args << (target.class == Class ? nil : target) #
return can_block.call(*block_args) # This makes testing a user's abilities very easy.
end #
end # def test "user can only destroy projects which he owns"
# user = User.new
# ability = Ability.new(user)
# assert ability.can?(:destroy, Project.new(:user => user))
# assert ability.cannot?(:destroy, Project.new)
# end
#
def can?(action, noun)
(@can_definitions || []).reverse.each do |base_behavior, defined_action, defined_noun, defined_block|
defined_actions = expand_actions(defined_action)
defined_nouns = [defined_noun].flatten
if includes_action?(defined_actions, action) && includes_noun?(defined_nouns, noun)
result = can_perform_action?(action, noun, defined_actions, defined_nouns, defined_block)
return base_behavior ? result : !result
end end
end end
false false
end end
# Convenience method which works the same as "can?" but returns the opposite value.
#
# cannot? :destroy, @project
#
def cannot?(*args) def cannot?(*args)
!can?(*args) !can?(*args)
end end
def possible_actions_for(initial_action) # Defines which abilities are allowed using two arguments. The first one is the action
actions = [initial_action] # you're setting the permission for, the second one is the class of object you're setting it on.
(@aliased_actions || default_alias_actions).each do |target, aliases| #
actions += possible_actions_for(target) if aliases.include? initial_action # can :update, Article
end #
actions # You can pass an array for either of these parameters to match any one.
#
# can [:update, :destroy], [Article, Comment]
#
# In this case the user has the ability to update or destroy both articles and comments.
#
# You can pass a block to provide logic based on the article's attributes.
#
# can :update, Article do |article|
# article && article.user == user
# end
#
# If the block returns true then the user has that :update ability for that article, otherwise he
# will be denied access. It's possible for the passed in model to be nil if one isn't specified,
# so be sure to take that into consideration.
#
# You can pass :all to reference every type of object. In this case the object type will be passed
# into the block as well (just in case object is nil).
#
# can :read, :all do |object_class, object|
# object_class != Order
# end
#
# Here the user has permission to read all objects except orders.
#
# You can also pass :manage as the action which will match any action. In this case the action is
# passed to the block.
#
# can :manage, Comment do |action, comment|
# action != :destroy
# end
#
# You can pass custom objects into this "can" method, this is usually done through a symbol
# and is useful if a class isn't available to define permissions on.
#
# can :read, :stats
# can? :read, :stats # => true
#
def can(action, noun, &block)
@can_definitions ||= []
@can_definitions << [true, action, noun, block]
end end
def can(action, target, &block) # Define an ability which cannot be done. Accepts the same arguments as "can".
@can_history ||= [] #
@can_history << [action, target, block] # can :read, :all
# cannot :read, Comment
#
# A block can be passed just like "can", however if the logic is complex it is recommended
# to use the "can" method.
#
# cannot :read, Product do |product|
# product.invisible?
# end
#
def cannot(action, noun, &block)
@can_definitions ||= []
@can_definitions << [false, action, noun, block]
end end
# Alias one or more actions into another one.
#
# alias_action :update, :destroy, :to => :modify
# can :modify, Comment
#
# Then :modify permission will apply to both :update and :destroy requests.
#
# can? :update, Comment # => true
# can? :destroy, Comment # => true
#
# This only works in one direction. Passing the aliased action into the "can?" call
# will not work because aliases are meant to generate more generic actions.
#
# alias_action :update, :destroy, :to => :modify
# can :update, Comment
# can? :modify, Comment # => false
#
# Unless that exact alias is used.
#
# can :modify, Comment
# can? :modify, Comment # => true
#
# The following aliases are added by default for conveniently mapping common controller actions.
#
# alias_action :index, :show, :to => :read
# alias_action :new, :to => :create
# alias_action :edit, :to => :update
#
# This way one can use params[:action] in the controller to determine the permission.
def alias_action(*args) def alias_action(*args)
@aliased_actions ||= default_alias_actions
target = args.pop[:to] target = args.pop[:to]
@aliased_actions[target] = args aliased_actions[target] = args
end
private
def aliased_actions
@aliased_actions ||= default_alias_actions
end end
def default_alias_actions def default_alias_actions
@@ -53,5 +172,35 @@ module CanCan
:update => [:edit], :update => [:edit],
} }
end end
def expand_actions(actions)
[actions].flatten.map do |action|
if aliased_actions[action]
[action, *aliased_actions[action]]
else
action
end
end.flatten
end
def can_perform_action?(action, noun, defined_actions, defined_nouns, defined_block)
if defined_block.nil?
true
else
block_args = []
block_args << action if defined_actions.include?(:manage)
block_args << (noun.class == Class ? noun : noun.class) if defined_nouns.include?(:all)
block_args << (noun.class == Class ? nil : noun)
return defined_block.call(*block_args)
end
end
def includes_action?(actions, action)
actions.include?(:manage) || actions.include?(action)
end
def includes_noun?(nouns, noun)
nouns.include?(:all) || nouns.include?(noun) || nouns.any? { |c| c.kind_of?(Class) && noun.kind_of?(c) }
end
end end
end end

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@@ -1,41 +1,113 @@
module CanCan module CanCan
# This module is automatically included into all controllers.
# It also makes the "can?" and "cannot?" methods available to all views.
module ControllerAdditions module ControllerAdditions
def self.included(base) def self.included(base)
base.helper_method :can?, :cannot? base.helper_method :can?, :cannot?
end end
# Raises the CanCan::AccessDenied exception. This is often used in a
# controller action to mark a request as unauthorized.
#
# def show
# @article = Article.find(params[:id])
# unauthorized! if cannot? :read, @article
# end
#
# You can rescue from the exception in the controller to specify
# the user experience.
#
# class ApplicationController < ActionController::Base
# rescue_from CanCan::AccessDenied, :with => :access_denied
#
# protected
#
# def access_denied
# flash[:error] = "Sorry, you are not allowed to access that page."
# redirect_to root_url
# end
# end
#
# See the load_and_authorize_resource method to automatically add
# the "unauthorized!" behavior to a RESTful controller's actions.
def unauthorized! def unauthorized!
raise AccessDenied, "You are unable to access this page." raise AccessDenied, "You are unable to access this page."
end end
# Creates and returns the current user's ability. You generally do not invoke
# this method directly, instead you can override this method to change its
# behavior if the Ability class or current_user method are different.
#
# def current_ability
# UserAbility.new(current_account) # instead of Ability.new(current_user)
# end
#
def current_ability def current_ability
::Ability.new(current_user) ::Ability.new(current_user)
end end
# 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 %>
#
# This simply calls "can?" on the current_ability. See Ability#can?.
def can?(*args) def can?(*args)
(@current_ability ||= current_ability).can?(*args) (@current_ability ||= current_ability).can?(*args)
end end
# Convenience method which works the same as "can?" but returns the opposite value.
#
# cannot? :destroy, @project
#
def cannot?(*args) def cannot?(*args)
(@current_ability ||= current_ability).cannot?(*args) (@current_ability ||= current_ability).cannot?(*args)
end end
def load_resource # TODO this could use some refactoring # This method loads the appropriate model resource into an instance variable. For example,
model_name = params[:controller].split('/').last.singularize # given an ArticlesController it will load the current article into the @article instance
unless params[:action] == "index" # variable. It does this by either calling Article.find(params[:id]) or
if params[:id] # Article.new(params[:article]) depending upon the action. It does nothing for the "index"
instance_variable_set("@#{model_name}", model_name.camelcase.constantize.find(params[:id])) # action.
else #
instance_variable_set("@#{model_name}", model_name.camelcase.constantize.new(params[model_name.to_sym])) # You would often use this as a before filter in the controller. See
end # load_and_authorize_resource to handle authorization too.
end #
# before_filter :load_resource
#
def load_resource
ResourceAuthorization.new(self, params).load_resource
end end
def authorize_resource # TODO this could use some refactoring # Authorizes the resource in the current instance variable. For example,
model_name = params[:controller].split('/').last.singularize # if you have an ArticlesController it will check the @article instance variable
unauthorized! unless can?(params[:action].to_sym, instance_variable_get("@#{model_name}") || model_name.camelcase.constantize) # and ensure the user can perform the current action on it.
# Under the hood it is doing something like the following.
#
# unauthorized! if cannot?(params[:action].to_sym, @article || Article)
#
# You would often use this as a before filter in the controller.
#
# before_filter :authorize_resource
#
# See load_and_authorize_resource to automatically load the resource too.
def authorize_resource
ResourceAuthorization.new(self, params).authorize_resource
end end
# Calls load_resource to load the current resource model into an instance variable.
# Then calls authorize_resource to ensure the current user is authorized to access the page.
# You would often use this as a before filter in the controller.
#
# before_filter :load_and_authorize_resource
#
def load_and_authorize_resource def load_and_authorize_resource
load_resource load_resource
authorize_resource authorize_resource

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@@ -0,0 +1,41 @@
module CanCan
class ResourceAuthorization # :nodoc:
attr_reader :params
def initialize(controller, params)
@controller = controller
@params = params
end
def load_and_authorize_resource
load_resource
authorize_resource
end
def load_resource
self.model_instance = params[:id] ? model_class.find(params[:id]) : model_class.new(params[model_name.to_sym]) unless params[:action] == "index"
end
def authorize_resource
@controller.unauthorized! if @controller.cannot?(params[:action].to_sym, model_instance || model_class)
end
private
def model_name
params[:controller].split('/').last.singularize
end
def model_class
model_name.camelcase.constantize
end
def model_instance
@controller.instance_variable_get("@#{model_name}")
end
def model_instance=(instance)
@controller.instance_variable_set("@#{model_name}", instance)
end
end
end

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@@ -99,4 +99,28 @@ describe CanCan::Ability do
@ability.can?(:update, []).should be_true @ability.can?(:update, []).should be_true
@ability.can?(:update, 123).should be_false @ability.can?(:update, 123).should be_false
end end
it "should support custom objects in the can definition" do
@ability.can :read, :stats
@ability.can?(:read, :stats).should be_true
@ability.can?(:update, :stats).should be_false
@ability.can?(:read, :nonstats).should be_false
end
it "should support 'cannot' method to define what user cannot do" do
@ability.can :read, :all
@ability.cannot :read, Integer
@ability.can?(:read, "foo").should be_true
@ability.can?(:read, 123).should be_false
end
it "should support block on 'cannot' method" do
@ability.can :read, :all
@ability.cannot :read, Integer do |int|
int > 5
end
@ability.can?(:read, "foo").should be_true
@ability.can?(:read, 3).should be_true
@ability.can?(:read, 123).should be_false
end
end end

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@@ -1,16 +1,10 @@
require File.dirname(__FILE__) + '/../spec_helper' require File.dirname(__FILE__) + '/../spec_helper'
class Ability
include CanCan::Ability
def initialize(user)
end
end
describe CanCan::ControllerAdditions do describe CanCan::ControllerAdditions do
before(:each) do before(:each) do
@controller_class = Class.new @controller_class = Class.new
@controller = @controller_class.new @controller = @controller_class.new
stub(@controller).params { {} }
mock(@controller_class).helper_method(:can?, :cannot?) mock(@controller_class).helper_method(:can?, :cannot?)
@controller_class.send(:include, CanCan::ControllerAdditions) @controller_class.send(:include, CanCan::ControllerAdditions)
end end
@@ -33,60 +27,19 @@ describe CanCan::ControllerAdditions do
@controller.cannot?(:foo, :bar).should be_true @controller.cannot?(:foo, :bar).should be_true
end end
it "should load the resource if params[:id] is specified" do it "should load resource" do
stub(@controller).params { {:controller => "abilities", :action => "show", :id => 123} } mock.instance_of(CanCan::ResourceAuthorization).load_resource
stub(Ability).find(123) { :some_resource }
@controller.load_resource @controller.load_resource
@controller.instance_variable_get(:@ability).should == :some_resource
end end
it "should build a new resource with hash if params[:id] is not specified" do it "should authorize resource" do
stub(@controller).params { {:controller => "abilities", :action => "create", :ability => {:foo => "bar"}} } mock.instance_of(CanCan::ResourceAuthorization).authorize_resource
stub(Ability).new(:foo => "bar") { :some_resource } @controller.authorize_resource
@controller.load_resource
@controller.instance_variable_get(:@ability).should == :some_resource
end end
it "should build a new resource even if attribute hash isn't specified" do it "should load and authorize resource in one call through controller" do
stub(@controller).params { {:controller => "abilities", :action => "new"} }
stub(Ability).new(nil) { :some_resource }
@controller.load_resource
@controller.instance_variable_get(:@ability).should == :some_resource
end
it "should not build a resource when on index action" do
stub(@controller).params { {:controller => "abilities", :action => "index"} }
@controller.load_resource
@controller.instance_variable_get(:@ability).should be_nil
end
it "should perform authorization using controller action and loaded model" do
@controller.instance_variable_set(:@ability, :some_resource)
stub(@controller).params { {:controller => "abilities", :action => "show"} }
stub(@controller).can?(:show, :some_resource) { false }
lambda {
@controller.authorize_resource
}.should raise_error(CanCan::AccessDenied)
end
it "should perform authorization using controller action and non loaded model" do
stub(@controller).params { {:controller => "abilities", :action => "show"} }
stub(@controller).can?(:show, Ability) { false }
lambda {
@controller.authorize_resource
}.should raise_error(CanCan::AccessDenied)
end
it "should load and authorize resource in one call" do
mock(@controller).load_resource mock(@controller).load_resource
stub(@controller).authorize_resource mock(@controller).authorize_resource
@controller.load_and_authorize_resource @controller.load_and_authorize_resource
end end
it "should properly load resource for namespaced controller" do
stub(@controller).params { {:controller => "admin/abilities", :action => "show", :id => 123} }
stub(Ability).find(123) { :some_resource }
@controller.load_resource
@controller.instance_variable_get(:@ability).should == :some_resource
end
end end

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@@ -0,0 +1,59 @@
require File.dirname(__FILE__) + '/../spec_helper'
describe CanCan::ResourceAuthorization do
before(:each) do
@controller = Object.new # simple stub for now
stub(@controller).unauthorized! { raise CanCan::AccessDenied }
end
it "should load the resource into an instance variable if params[:id] is specified" do
stub(Ability).find(123) { :some_resource }
authorization = CanCan::ResourceAuthorization.new(@controller, :controller => "abilities", :action => "show", :id => 123)
authorization.load_resource
@controller.instance_variable_get(:@ability).should == :some_resource
end
it "should properly load resource for namespaced controller" do
stub(Ability).find(123) { :some_resource }
authorization = CanCan::ResourceAuthorization.new(@controller, :controller => "admin/abilities", :action => "show", :id => 123)
authorization.load_resource
@controller.instance_variable_get(:@ability).should == :some_resource
end
it "should build a new resource with hash if params[:id] is not specified" do
stub(Ability).new(:foo => "bar") { :some_resource }
authorization = CanCan::ResourceAuthorization.new(@controller, :controller => "abilities", :action => "create", :ability => {:foo => "bar"})
authorization.load_resource
@controller.instance_variable_get(:@ability).should == :some_resource
end
it "should build a new resource even if attribute hash isn't specified" do
stub(Ability).new(nil) { :some_resource }
authorization = CanCan::ResourceAuthorization.new(@controller, :controller => "abilities", :action => "new")
authorization.load_resource
@controller.instance_variable_get(:@ability).should == :some_resource
end
it "should not build a resource when on index action" do
authorization = CanCan::ResourceAuthorization.new(@controller, :controller => "abilities", :action => "index")
authorization.load_resource
@controller.instance_variable_get(:@ability).should be_nil
end
it "should perform authorization using controller action and loaded model" do
@controller.instance_variable_set(:@ability, :some_resource)
stub(@controller).cannot?(:show, :some_resource) { true }
authorization = CanCan::ResourceAuthorization.new(@controller, :controller => "abilities", :action => "show")
lambda {
authorization.authorize_resource
}.should raise_error(CanCan::AccessDenied)
end
it "should perform authorization using controller action and non loaded model" do
stub(@controller).cannot?(:show, Ability) { true }
authorization = CanCan::ResourceAuthorization.new(@controller, :controller => "abilities", :action => "show")
lambda {
authorization.authorize_resource
}.should raise_error(CanCan::AccessDenied)
end
end

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@@ -9,3 +9,10 @@ require File.dirname(__FILE__) + '/../lib/cancan.rb'
Spec::Runner.configure do |config| Spec::Runner.configure do |config|
config.mock_with :rr config.mock_with :rr
end end
class Ability
include CanCan::Ability
def initialize(user)
end
end