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updating readme and documentation
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ryanb committed Oct 5, 2010
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2 changes: 1 addition & 1 deletion LICENSE
@@ -1,4 +1,4 @@
Copyright (c) 2009 Ryan Bates
Copyright (c) 2010 Ryan Bates

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
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44 changes: 23 additions & 21 deletions README.rdoc
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Wiki[http://wiki.github.com/ryanb/cancan] | RDocs[http://rdoc.info/projects/ryanb/cancan] | Screencast[http://railscasts.com/episodes/192-authorization-with-cancan]

CanCan is an authorization solution for Ruby on Rails for restricting what a given user is allowed to access throughout the application. It does not care how your user roles are defined, it simply focusses on keeping permission logic in a single location (the +Ability+ class) so it is not duplicated across controllers, views, and database queries.

By default, the +current_user+ method is required, so if you have not already, set up some authentication (such as Authlogic[http://github.com/binarylogic/authlogic] or Devise[http://github.com/plataformatec/devise]). See {Changing Defaults}[http://wiki.github.com/ryanb/cancan/changing-defaults] if you need different behavior.
CanCan is an authorization library for Ruby on Rails which restricts what resources a given user is allowed to access. All permissions are defined in a single location (the +Ability+ class) and not duplicated across controllers, views, and database queries.


== Installation

To install CanCan, include the gem in the environment.rb in Rails 2.3.
In <b>Rails 3</b>, add this to your Gemfile.

config.gem "cancan"
gem "cancan"

Or the Gemfile in Rails 3.
In <b>Rails 2</b>, add this to your environment.rb file.

gem "cancan"
config.gem "cancan"

Alternatively it can be installed as a plugin.
Alternatively, you can install it as a plugin.

script/plugin install git://github.com/ryanb/cancan.git
rails plugin install git://github.com/ryanb/cancan.git


== Getting Started

First, define a class called +Ability+ in "models/ability.rb" or anywhere else in the load path. It should look something like this.
CanCan expects a +current_user+ method to exist. If you have not already, set up some authentication (such as Authlogic[http://github.com/binarylogic/authlogic] or Devise[http://github.com/plataformatec/devise]). See {Changing Defaults}[http://wiki.github.com/ryanb/cancan/changing-defaults] if you need different behavior.

Next create a class called +Ability+ in "models/ability.rb" or anywhere else in the load path. It should look similar to this.

class Ability
include CanCan::Ability
Expand All @@ -38,7 +38,7 @@ First, define a class called +Ability+ in "models/ability.rb" or anywhere else i
end
end

This is where all permissions will go. See the "Defining Abilities" section below for more information.
The +current_user+ is passed in to this method which is where the abilities are defined. See the "Defining Abilities" section below for more information.

The current user's permissions can be accessed using the "can?" and "cannot?" methods in the view and controller.

Expand Down Expand Up @@ -67,11 +67,11 @@ Setting this for every action can be tedious, therefore the +load_and_authorize_

See {Authorizing Controller Actions}[http://wiki.github.com/ryanb/cancan/authorizing-controller-actions] for more information

If the user authorization fails, a CanCan::AccessDenied exception will be raised. You can catch this and modify its behavior in the +ApplicationController+.
If the user authorization fails, a <tt>CanCan::AccessDenied</tt> exception will be raised. You can catch this and modify its behavior in the +ApplicationController+.

class ApplicationController < ActionController::Base
rescue_from CanCan::AccessDenied do |exception|
flash[:error] = exception.message
flash[:alert] = exception.message
redirect_to root_url
end
end
Expand All @@ -81,7 +81,7 @@ See {Exception Handling}[http://wiki.github.com/ryanb/cancan/exception-handling]

== Defining Abilities

As shown above, the +Ability+ class is where all user permissions are defined. The user model is passed into the initialize method so the permissions can be modified based on any user attributes. CanCan makes no assumptions about how roles are handled in your application. See {Role Based Authorization}[http://wiki.github.com/ryanb/cancan/role-based-authorization] for an example.
As shown above, the +Ability+ class is where all user permissions are defined. The current user model is passed into the initialize method so the permissions can be modified based on any user attributes. CanCan makes no assumption about how roles are handled in your application. See {Role Based Authorization}[http://wiki.github.com/ryanb/cancan/role-based-authorization] for an example.

The +can+ method is used to define permissions and requires 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.

Expand All @@ -97,7 +97,7 @@ Use :+manage+ to represent any action and :+all+ to represent any class. Here ar
can :read, :all # has permission to read any model
can :manage, :all # has permission to do anything to any model

You can pass a hash of conditions as the third argument to further restrict what the user is able to access. Here the user will only have permission to read active projects which he owns.
You can pass a hash of conditions as the third argument to further define what the user is able to access. Here the user will only have permission to read active projects which he owns.

can :read, Project, :active => true, :user_id => user.id

Expand All @@ -106,10 +106,10 @@ See {Defining Abilities with Hashes}[http://wiki.github.com/ryanb/cancan/definin
Blocks can also be used if you need more control.

can :update, Project do |project|
project && project.groups.include?(user.group)
project.groups.include?(user.group)
end

If the block returns true then the user has that :+update+ ability for that project, otherwise he will be denied access. See {Defining Abilities with Blocks}[http://wiki.github.com/ryanb/cancan/defining-abilities-with-blocks] for more information.
If the block returns true then the user has that ability for that project, otherwise he will be denied access. See {Defining Abilities with Blocks}[http://wiki.github.com/ryanb/cancan/defining-abilities-with-blocks] for more information.


== Aliasing Actions
Expand All @@ -120,7 +120,7 @@ You will usually be working with four actions when defining and checking permiss
alias_action :new, :to => :create
alias_action :edit, :to => :update

Notice the +edit+ action is aliased to +update+. If the user is able to update a record he also has permission to edit it. You can define your own aliases in the +Ability+ class
Notice the +edit+ action is aliased to +update+. This means if the user is able to update a record he also has permission to edit it. You can define your own aliases in the +Ability+ class.

alias_action :update, :destroy, :to => :modify
can :modify, Comment
Expand All @@ -131,16 +131,18 @@ The +alias_action+ method is an instance method and usually called in +initializ

== Fetching Records

In the controller +index+ action you may want to fetch only the records which the user has permission to read. You can do this with the +accessible_by+ scope.
It is possible to fetch records which the user has permission to read using the +accessible_by+ scope in Active Record.

@articles = Article.accessible_by(current_ability)

Since version 1.4 this is done automatically when loading resources in the index action, so one rarely needs to do it manually.

This will only work when abilities are defined using hash conditions, not blocks. See {Fetching Records}[http://wiki.github.com/ryanb/cancan/fetching-records] for more information.


== Additional Docs

* {Upgrading to 1.3}[http://wiki.github.com/ryanb/cancan/upgrading-to-13]
* {Upgrading to 1.4}[http://github.com/ryanb/cancan/wiki/Upgrading-to-1.4]
* {Nested Resources}[http://wiki.github.com/ryanb/cancan/nested-resources]
* {Testing Abilities}[http://wiki.github.com/ryanb/cancan/testing-abilities]
* {Accessing Request Data}[http://wiki.github.com/ryanb/cancan/accessing-request-data]
Expand All @@ -150,7 +152,7 @@ This will only work when abilities are defined using hash conditions, not blocks

== Questions or Problems?

If you have any issues with CanCan which you cannot find the solution to in the documentation, please add an {issue on GitHub}. Or better yet, fork the project and make a pull request.
If you have any issues with CanCan which you cannot find the solution to in the documentation, please add an {issue on GitHub}[http://github.com/ryanb/cancan/issues] or fork the project and send a pull request.

To get the specs running you should call +bundle+ and then +rake+. Specs currently do not work in Ruby 1.9 due to the RR mocking framework.

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6 changes: 3 additions & 3 deletions lib/cancan/controller_additions.rb
Expand Up @@ -18,8 +18,8 @@ def load_and_authorize_resource(*args)
# Sets up a before filter which loads the model resource into an instance variable.
# For example, given an ArticlesController it will load the current article into the @article
# instance variable. It does this by either calling Article.find(params[:id]) or
# Article.new(params[:article]) depending upon the action. It does nothing for the "index"
# action.
# Article.new(params[:article]) depending upon the action. The index action will
# automatically set @articles to Article.accessible_by(current_ability).
#
# If a conditions hash is used in the Ability, the +new+ and +create+ actions will set
# the initial attributes based on these conditions. This way these actions will satisfy
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# en:
# unauthorized:
# manage:
# all: "Not authorized to perform that action."
# all: "Not authorized to %{action} %{subject}."
# user: "Not allowed to manage other user accounts."
# update:
# project: "Not allowed to update this project."
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