releasing gem 0.2.0 NOT BACKWARDS COMPATABLE, SEE CHANGELOG

CHANGELOG.rdoc

@@ -1,3 +1,14 @@
-*0.1.0* (Nov 16th, 2009)
+0.2.0 (Nov 17, 2009)
+
+* fix behavior of load_and_authorize_resource for namespaced controllers - see issue #3
+
+* support arrays being passed to "can" to specify multiple actions or classes - see issue #2
+
+* adding "cannot?" method to ability, controller, and view which is inverse of "can?" - see issue #1
+
+* BACKWARDS INCOMPATIBLE: use Ability#initialize instead of 'prepare' to set up abilities - see issue #4
+
+
+0.1.0 (Nov 16, 2009)
 
 * initial release

README.rdoc

@@ -1,8 +1,8 @@
 = CanCan
 
-This is a simple authorization solution for Rails which is completely decoupled from how you set up the user's roles. All permissions are stored in a single location for convenience.
+This is a simple authorization solution for Ruby on Rails to restrict what a given user is allowed to access in the application. This is completely decoupled from any role based implementation allowing you to define user roles the way you want. All permissions are stored in a single location for convenience.
 
-This assumes you already have an authentication solution (such as Authlogic) which proves a current_user model.
+This assumes you already have authentication (such as Authlogic[http://github.com/binarylogic/authlogic]) which provides a current_user model.
 
 
 == Installation
@@ -13,7 +13,7 @@ You can set it up as a gem in your environment.rb file.
   
 And then install the gem.
 
-  gem install cancan
+  sudo rake gems:install
 
 Alternatively you can install it as a Rails plugin.
 
@@ -22,12 +22,12 @@ Alternatively you can install it as a Rails plugin.
 
 == Setup
 
-First define a class called Ability, place it in "models/ability.rb".
+First, define a class called Ability in "models/ability.rb".
 
   class Ability
     include CanCan::Ability
   
-    def prepare(user)
+    def initialize(user)
       if user.admin?
         can :manage, :all
       else
@@ -36,22 +36,22 @@ First define a class called Ability, place it in "models/ability.rb".
     end
   end
 
-This class is where all permissions will go. See the "Defining Abilities" section below for more information.
+This is where all permissions will go. See the "Defining Abilities" section below for more information.
 
-In the view layer you can access the current permissions at any point using the "can?" method. See "Checking Abilities" section below.
+You can access the current permissions at any point using the "can?" and "cannot?" methods in the view.
 
   <% if can? :update, @article %>
     <%= link_to "Edit", edit_article_path(@article) %>
   <% end %>
 
-You can also use this method in the controller layer along with the "unauthorized!" method to restrict access.
+You can also use these methods in a controller along with the "unauthorized!" method to restrict access.
 
   def show
     @article = Article.find(params[:id])
-    unauthorized! unless can? :read, @article
+    unauthorized! if cannot? :read, @article
   end
 
-Setting this for every action can be tedious, therefore a before filter is also provided for automatically applying this setting to a RESTful style resource controller.
+Setting this for every action can be tedious, therefore a before filter is also provided to automatically authorize all actions in a RESTful style resource controller.
 
   class ArticlesController < ApplicationController
     before_filter :load_and_authorize_resource
@@ -61,7 +61,7 @@ Setting this for every action can be tedious, therefore a before filter is also
     end
   end
 
-If the user authorization fails, a CanCan::AccessDenied exception will be raised. You can catch this and modify its behavior.
+If the user authorization fails, a CanCan::AccessDenied exception will be raised. You can catch this and modify its behavior in the ApplicationController.
 
   class ApplicationController < ActionController::Base
     rescue_from CanCan::AccessDenied, :with => :access_denied
@@ -77,7 +77,7 @@ If the user authorization fails, a CanCan::AccessDenied exception will be raised
 
 == Defining Abilities
 
-As shown above, the Ability#prepare method is where all user permissions are defined. The user model is passed into this method so you are free to modify the permissions based on the user's attributes. This way CanCan is completely decoupled with how you choose to handle roles.
+As shown above, the Ability class is where all user permissions are defined. The user model is passed into the initialize method so you are free to modify the permissions based on the user's attributes. This way CanCan is completely decoupled with how you choose to handle roles.
 
 The "can" method accepts two arguments, the first one is the action you're setting the permission for, the second one is the class of object you're setting it on.
 
@@ -89,7 +89,7 @@ You can pass an array for either of these parameters to match any one.
 
 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. For example:
+You can pass a block to provide logic based on the article's attributes.
 
   can :update, Article do |article|
     article && article.user == user
@@ -129,16 +129,20 @@ Use the "can?" method in the controller or view to check the user's permission f
 
   can? :destroy, @project
 
-You can also pass the class instead of an instance (if you don't have one handy). For example:
+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 %>
 
+The "cannot?" method is for convenience and performs the opposite check of "can?"
+
+  cannot? :destroy, @project
+
 
 == Custom Actions
 
-There is no limit to what actions you can use to determine abilities. For example, if only pro users are allowed to upload a picture for their product, you might add restrictions like this.
+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.
 
   # ability.rb
   can :upload_picture, Project if user.pro?
@@ -148,24 +152,22 @@ There is no limit to what actions you can use to determine abilities. For exampl
   
   # projects_controller.rb
   def update
-    unauthorized! if params[:project][:upload_picture] && !can?(:upload_picture, @project)
+    unauthorized! if params[:project][:upload_picture] && cannot?(:upload_picture, @project)
     # ...
   end
 
 
-== Customizing Assumptions
+== Assumptions & Configuring
 
 CanCan makes two assumptions about your application.
 
-  * The permissions are defined in Ability#prepare.
-  * The user is fetched with current_user method in the controller.
+* You have an Ability class which defines the permissions.
+* You have a current_user method in the controller which returns the current user model.
 
-You can override these by defining the "current_ability" method in your ApplicationController.
+You can override these by overriding the "current_ability" method in your ApplicationController.
 
    def current_ability
-     ability = UserAbility.new          # instead of Ability
-     ability.prepare(current_account)   # instead of current_user
-     ability                            # be sure to return the ability
+     UserAbility.new(current_account) # instead of Ability.new(current_user)
    end
 
 That's it!
@@ -180,14 +182,41 @@ For example, let's assume that each user has_many :permissions, and each permiss
   class Ability
     include CanCan::Ability
   
-    def prepare(user)
+    def initialize(user)
       can :manage, :all do |action, object_class, object|
         user.permissions.find_all_by_action(action).any? do |permission|
-          permission.object_type.constantize == object_class &&
+          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
+
+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"
+  user = User.new
+  ability = Ability.new(user)
+  assert ability.can?(:destroy, Project.new(:user => user))
+  assert ability.cannot?(:destroy, Project.new)
+end
+
+
+== Special Thanks
+
+CanCan was inspired by declarative_authorization[http://github.com/stffn/declarative_authorization/] and aegis[http://github.com/makandra/aegis]. Many thanks to the authors and contributors.

cancan.gemspec

@@ -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.homepage = "http://github.com/ryanb/cancan"
   
-  s.version = "0.1.0"
-  s.date = "2009-11-16"
+  s.version = "0.2.0"
+  s.date = "2009-11-17"
   
   s.authors = ["Ryan Bates"]
   s.email = "ryan@railscasts.com"

lib/cancan/ability.rb

@@ -4,14 +4,16 @@ module CanCan
     
     def can?(original_action, target) # TODO this could use some refactoring
       (@can_history || []).reverse.each do |can_action, can_target, can_block|
+        can_actions = [can_action].flatten
+        can_targets = [can_target].flatten
         possible_actions_for(original_action).each do |action|
-          if (can_action == :manage || can_action == action) && (can_target == :all || can_target == target || target.kind_of?(can_target))
+          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?
               return true
             else
               block_args = []
-              block_args << action if can_action == :manage
-              block_args << (target.class == Class ? target : target.class) if can_target == :all
+              block_args << action if can_actions.include?(:manage)
+              block_args << (target.class == Class ? target : target.class) if can_targets.include?(:all)
               block_args << (target.class == Class ? nil : target)
               return can_block.call(*block_args)
             end
@@ -21,6 +23,10 @@ module CanCan
       false
     end
     
+    def cannot?(*args)
+      !can?(*args)
+    end
+    
     def possible_actions_for(initial_action)
       actions = [initial_action]
       (@aliased_actions || default_alias_actions).each do |target, aliases|
@@ -47,9 +53,5 @@ module CanCan
         :update => [:edit],
       }
     end
-    
-    def prepare(user)
-      # to be overriden by included class
-    end
   end
 end

lib/cancan/controller_additions.rb

@@ -1,7 +1,7 @@
 module CanCan
   module ControllerAdditions
     def self.included(base)
-      base.helper_method :can?
+      base.helper_method :can?, :cannot?
     end
     
     def unauthorized!
@@ -9,27 +9,31 @@ module CanCan
     end
     
     def current_ability
-      ability = ::Ability.new
-      ability.prepare(current_user)
-      ability
+      ::Ability.new(current_user)
     end
     
     def can?(*args)
       (@current_ability ||= current_ability).can?(*args)
     end
     
+    def cannot?(*args)
+      (@current_ability ||= current_ability).cannot?(*args)
+    end
+    
     def load_resource # TODO this could use some refactoring
+      model_name = params[:controller].split('/').last.singularize
       unless params[:action] == "index"
         if params[:id]
-          instance_variable_set("@#{params[:controller].singularize}", params[:controller].singularize.camelcase.constantize.find(params[:id]))
+          instance_variable_set("@#{model_name}", model_name.camelcase.constantize.find(params[:id]))
         else
-          instance_variable_set("@#{params[:controller].singularize}", params[:controller].singularize.camelcase.constantize.new(params[params[:controller].singularize.to_sym]))
+          instance_variable_set("@#{model_name}", model_name.camelcase.constantize.new(params[model_name.to_sym]))
         end
       end
     end
     
     def authorize_resource # TODO this could use some refactoring
-      unauthorized! unless can?(params[:action].to_sym, instance_variable_get("@#{params[:controller].singularize}") || params[:controller].singularize.camelcase.constantize)
+      model_name = params[:controller].split('/').last.singularize
+      unauthorized! unless can?(params[:action].to_sym, instance_variable_get("@#{model_name}") || model_name.camelcase.constantize)
     end
     
     def load_and_authorize_resource
@@ -43,4 +47,4 @@ if defined? ActionController
   ActionController::Base.class_eval do
     include CanCan::ControllerAdditions
   end
-end
+end

spec/cancan/ability_spec.rb

@@ -78,7 +78,25 @@ describe CanCan::Ability do
     @ability.can?(:edit, 123).should == :update_called
   end
   
-  it "should respond to prepare" do
-    @ability.should respond_to(:prepare)
+  it "should not respond to prepare (now using initialize)" do
+    @ability.should_not respond_to(:prepare)
+  end
+  
+  it "should offer cannot? method which is simply invert of can?" do
+    @ability.cannot?(:tie, String).should be_true
+  end
+  
+  it "should be able to specify multiple actions and match any" do
+    @ability.can [:read, :update], :all
+    @ability.can?(:read, 123).should be_true
+    @ability.can?(:update, 123).should be_true
+    @ability.can?(:count, 123).should be_false
+  end
+  
+  it "should be able to specify multiple classes and match any" do
+    @ability.can :update, [String, Array]
+    @ability.can?(:update, "foo").should be_true
+    @ability.can?(:update, []).should be_true
+    @ability.can?(:update, 123).should be_false
   end
 end

spec/cancan/controller_additions_spec.rb

@@ -2,13 +2,16 @@ require File.dirname(__FILE__) + '/../spec_helper'
 
 class Ability
   include CanCan::Ability
+  
+  def initialize(user)
+  end
 end
 
 describe CanCan::ControllerAdditions do
   before(:each) do
     @controller_class = Class.new
     @controller = @controller_class.new
-    mock(@controller_class).helper_method(:can?)
+    mock(@controller_class).helper_method(:can?, :cannot?)
     @controller_class.send(:include, CanCan::ControllerAdditions)
   end
   
@@ -23,10 +26,11 @@ describe CanCan::ControllerAdditions do
     @controller.current_ability.should be_kind_of(Ability)
   end
   
-  it "should provide a can? method which goes through the current ability" do
+  it "should provide a can? and cannot? methods which go through the current ability" do
     stub(@controller).current_user { :current_user }
     @controller.current_ability.should be_kind_of(Ability)
     @controller.can?(:foo, :bar).should be_false
+    @controller.cannot?(:foo, :bar).should be_true
   end
   
   it "should load the resource if params[:id] is specified" do
@@ -78,4 +82,11 @@ describe CanCan::ControllerAdditions do
     stub(@controller).authorize_resource
     @controller.load_and_authorize_resource
   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