From 3c68a911d04641b05a6a037228e08a60c6da317e Mon Sep 17 00:00:00 2001
From: Ryan Bates <ryan@railscasts.com>
Date: Thu, 15 Apr 2010 17:04:36 -0700
Subject: [PATCH] adding can method to Active Record for fetching records
 matching a specific ability, still needs documentation

---
 CHANGELOG.rdoc                              |  2 ++
 lib/cancan.rb                               |  1 +
 lib/cancan/active_record_additions.rb       | 20 +++++++++++++++++++
 spec/cancan/active_record_additions_spec.rb | 22 +++++++++++++++++++++
 4 files changed, 45 insertions(+)
 create mode 100644 lib/cancan/active_record_additions.rb
 create mode 100644 spec/cancan/active_record_additions_spec.rb

diff --git a/CHANGELOG.rdoc b/CHANGELOG.rdoc
index 025a8f0..2bd5161 100644
--- a/CHANGELOG.rdoc
+++ b/CHANGELOG.rdoc
@@ -1,5 +1,7 @@
 1.1.0 (not released)
 
+* Adding "can" method to Active Record for fetching records matching a specific ability
+
 * Adding conditions behavior to Ability#can and fetch with Ability#conditions - see issue #53
 
 * Renaming :class option to :resource for load_and_authorize_resource which now supports a symbol for non models - see issue #45
diff --git a/lib/cancan.rb b/lib/cancan.rb
index b39cf93..95ef16e 100644
--- a/lib/cancan.rb
+++ b/lib/cancan.rb
@@ -11,3 +11,4 @@ require 'cancan/ability'
 require 'cancan/controller_resource'
 require 'cancan/resource_authorization'
 require 'cancan/controller_additions'
+require 'cancan/active_record_additions'
diff --git a/lib/cancan/active_record_additions.rb b/lib/cancan/active_record_additions.rb
new file mode 100644
index 0000000..1bfe9d3
--- /dev/null
+++ b/lib/cancan/active_record_additions.rb
@@ -0,0 +1,20 @@
+module CanCan
+  # This module is automatically included into all Active Record.
+  module ActiveRecordAdditions
+    module ClassMethods
+      def can(ability, action)
+        where(ability.conditions(action, self) || {:id => nil})
+      end
+    end
+    
+    def self.included(base)
+      base.extend ClassMethods
+    end
+  end
+end
+
+if defined? ActiveRecord
+  ActiveRecord::Base.class_eval do
+    include CanCan::ActiveRecordAdditions
+  end
+end
diff --git a/spec/cancan/active_record_additions_spec.rb b/spec/cancan/active_record_additions_spec.rb
new file mode 100644
index 0000000..4e4628a
--- /dev/null
+++ b/spec/cancan/active_record_additions_spec.rb
@@ -0,0 +1,22 @@
+require "spec_helper"
+
+describe CanCan::ActiveRecordAdditions do
+  before(:each) do
+    @model_class = Class.new
+    stub(@model_class).where { :where_stub }
+    @model_class.send(:include, CanCan::ActiveRecordAdditions)
+    @ability = Object.new
+    @ability.extend(CanCan::Ability)
+  end
+  
+  it "should call where(:id => nil) when no ability is defined so no records are found" do
+    stub(@model_class).where(:id => nil) { :no_where }
+    @model_class.can(@ability, :read).should == :no_where
+  end
+  
+  it "should call where with matching ability conditions" do
+    @ability.can :read, @model_class, :foo => 1
+    stub(@model_class).where(:foo => 1) { :found_records }
+    @model_class.can(@ability, :read).should == :found_records
+  end
+end