Acl9 is a role-based authorization system that provides a concise DSL for securing your Rails application.
Access control is pointless if you're not sure you've done it right. The fundamental goal of acl9 is to ensure that your rules are easy to understand and easy to test - in other words acl9 makes it easy to ensure you've got your permissions correct.
Acl9 is Semantically Versioned, so just add this to your
gem 'acl9', '~> 2.0'
You will need Ruby 2.x
We dropped support for Rails < 4 in the 1.x releases, so if you're still using Rails 2.x or 3.x then you'll want this:
gem 'acl9', '~> 0.12'
The simplest way to demonstrate this is with some examples.
You declare the access control directly in your controller, so it's visible and obvious for any developer looking at the controller:
class Admin::SchoolsController < ApplicationController access_control do allow :support, :of => School allow :admins, :managers, :teachers, :of => :school deny :teachers, :only => :destroy action :index do allow anonymous, logged_in end allow logged_in, :only => :show deny :students end def index # ... end # ... end
You can see more about all this stuff in the wiki under Access Control Subsystem
The other side of acl9 is where you give and remove roles to and from a user. As you're looking through these examples refer back to the Access Control example and you should be able to see which access control rule each role corresponds to.
Let's say we want to create an admin of a given school, not a global admin, just the admin for a particular school:
user.has_role! :admin, school user.has_role! :admin, of: school
Then let's say we have some support people in our organization who are dedicated
to supporting all the schools. We could do two things, either we could come up
with a new role name like
:school_support or we can use the fact that we can
assign roles to any object, including a class, and do this:
user.has_role! :support, School user.has_role! :support, for: School
You can see the
allow line in our
access_control block that this corresponds
with. If we had used
:school_support instead then that line would have to be:
Now, when a support person leaves that team, we need to remove that role:
user.has_no_role! :support, School user.has_no_role! :support, at: School
You can see more about all this stuff in the wiki under Role Subsystem
As mentioned in Role Subsystem you
don't have to use these, if your role system is very simple all you need is a
has_role? method in your subject model that returns a boolean and the Access
Control part of Acl9 will work from that.
However, most commonly, the roles and role assignments are stored in two new tables that you create specifically for Acl9. There's a rails generator for creating the migrations, role model and updating the subject model and optionally any number of object models.
You can view the USAGE for this generator by running the following in your app directory:
bin/rails g acl9:setup -h
There are five configurable settings. These all have sensible defaults which can
be easily overridden in
You can also override each of the
:default_* settings (dropping the "default_"
prefix) in your models/controllers - see below for more detail:
'Role' and can be overridden in your "user" model, see the wiki for more.
:role_objects and can be overridden in
your "user" model, see the wiki for more.
We chose a name for this association that was unlikely to conflict with
existing models but a lot of people override this to be just
'User' and can be overridden in your
"role" model, see the wiki for more.
:current_user and can be overridden in
your controllers, see the wiki for more.
This is set to
nil by default, which will mean it will use the Rails method of
calculating the join table name for a
users_roles). Remember that if you override this value, either do it before
rails g acl9:setup or be sure to update your migration or database.
true (see "Upgrade Notes" below if you're upgrading) and can only be
changed by setting it in
Acl9.config. When true this causes Acl9 to normalize
your role names, normalization is
.to_s.underscore.singularize. This is done
on both the setter and getter.
true (see "Upgrade Notes" below if you're upgrading) and can only be
changed by merging into
Acl9.config. This setting changes how global roles
(ie. roles with no object) are treated.
Say we set a role like so:
user.has_role! :admin, school
true (as is the default) then
false. Ie. changing the role on a specific instance doesn't impact
the global role (hence the name).
user.has_role? :admin is
Ie. setting a role on a specific instance makes that person a global one of
Basically these are just two different ways of working with roles, if you're protecting your global roles then you can use them as sort of a superuser version of a given role. So you can have an admin of a school and a global admin with different privileges.
If you don't protect your global roles then you can use them as a catch-all for
any specific roles, so then the admins of schools, classrooms and students can
all be granted a privilege by allowing the global
# config/initializers/acl9.rb Acl9.config.default_association_name = :roles # or... Acl9.configure do |c| c.default_association_name = :roles end
On the off chance that you ever need to reset the config back to its default you can use:
Acl9 now protects global roles by default
Please, PLEASE, PLEASE note. If you're upgrading from the
0.x series of acl9
then there's an important change in one of the defaults for
1.x. We flipped
the default value of
Say you had a role on an object:
user.has_role! :manager, department
We all know that this means:
user.has_role? :manager, department # => true user.has_role? :manager, in: department # => true
:protect_global_roles set to
false, as it was in
0.x then the above
role would mean that the global
:manager role would also be
Ie. this is how
user.has_role? :manager # => true
1.x we default
true which means that the
:manager role is protected, ie:
user.has_role? :manager # => false
In words, in 1.x just because you're the
:manager of a
doesn't make you a global
Acl9 now normalizes role names by default
So basically we downcase, underscore, and singularize your role names, so:
user.has_role! 'FooBars' user.has_role? 'FooBars' # => true user.has_role? :foo_bar # => true user.has_role! :foo_bar # => nil, because it was already set above
If you're upgrading then you will want to do something like this:
Role.all.each do |role| role.update! name: role.name.underscore.singularize end
Then check for any duplicates and resolve those manually.
Acl9 now raises ArgumentError on bad args to
In 2.x and above we now try to help the developer by raising ArgumentError if
they mess up with the options they pass to
deny, this prevents people
doing things that they think are going to work but actually aren't like:
allow all, actions: [ :index, :show ] # <---- BROKEN!!
IRC: Please drop in for a chat on #acl9 on Freenode, use this if you have no other option.
docs: Rdocs are available here.
StackOverflow: Go ask (or answer) a question on StackOverflow
Mailing list: We have an old skule mailing list as well acl9-discuss group
Contributing: Last but not least, check out the Contributing Guide if you want to get even more involved
All these people are awesome! as are all the people who have raised or investigated issues.