# ActsPermissive

This is a library that allows you to create arbitrary permissions on arbitrary groupings
of individual Rails models

What?

I know, that's confusing. But it's really cool once you get it. Keep reading.

# Installation

## Rails 3.1
    gem 'acts_permissive', :git => 'git://github.com/mettadore/acts_permissive.git', :branch => 'rails_3.1'

    bundle install

    rails generate acts_permissive

    rake db:migrate

## Loading

Somewhere in the initialisation (e.g. application.rb), define your arbitrary permissions:

    module ActsPermissive::PermissionMap
      VISIT = 0
      USE = 1
      HIDE = 2
      THROW_AWAY = 3
      READ = 4
      WRITE = 5
    end

User-like classes (things that have permissions) are loaded like this:

    class User < ActiveResource::Base
      acts_permissive
    end

    class Admin < ActiveResource::Base
      acts_permissive
    end

Thing-like classes (things that you want to control permissions for) are loaded like this:

    class Thing < ActiveResource::Base
      is_used_permissively
    end

    class Widget < ActiveResource::Base
      is_used_permissively
    end

# Usage
It's all a bit complicated to talk about, because we're not used to being able to do this, but basically:

    private_circle = user_a.build_circle :name => "My Private Stuff"
    friend_circle = user_a.build_circle :name => "Stuff for my friends"

    journal = Thing.create :name => "Journal"
    photo = Widget.create :name => "photos"


    journal.is_used_permissively? -> true

    journal.add_to private_circle
    photo.add_to public_circle

    friend = User.create :name => "friend"
    foe = Admin.create :name => "foe"

    friend.acts_permissive? -> true
    foe.acts_permissive? -> true

    friend.can! :read, :write, :in => public_circle
    friend.can! :read, :in => private_circle

    friend.can?(:read, :in => private_circle) -> true
    friend.can?(:write, :in => private_circle) -> false
    friend.can?(:read, journal) -> true
    friend.can?(:write, journal) -> false
    friend.can?(:read, photo) -> true

    foe.can?(:read, :in => public_circle) -> false
    foe.can?(:read, :in => private_circle) -> false

    journal.all_who_can(:read).include?(friend) -> true


## Bigger example (i.e. Who's allowed in your bedroom?)

Think about the 'circle of trust.' You have a house, and certain people are allowed in your house.
It's not everyone in the world, it's people in your "house circle of trust." Of all the people in
your house, a certain sub-set of them are allowed, say, in your bedroom-- you have a separate
"bedroom circle of trust." Now, friends might come over and hang out in your bedroom and watch
a scary movie with you, but not all of them are allowed, say, in your underwear drawer-- that's
an even smaller "underwear drawer circle of trust."

That's how acts_permissive works. It's based on the "circle of trust" for specific collections
 of Rails objects.

So, there are some people. There's me:

    john = User.create :name => "John"

and there are others:

    wife = User.create :name => "Jessica"
    buddy = User.create :name => "Bill"
    boss = Admin.create :name => "Hugh"

And there are some things that I want to control access to:

    tv = Thing.create :name => "television"
    couch = Thing.create :name => "couch"
    stapler = Widget.create :name => "Swingline"
    toothbrush = Widget.create :name => "toothbrush"

So, I make some "access control groupings" (i.e. circles of trust)

    public = john.build_circle :name => "My House"
    private = john.build_circle :name => "My Bedroom"
    world = john.build_circle :name => "Everything"

And I put the "things" in the "circles"

    tv.add_to public, world
    couch.add_to public, world
    stapler.add_to private, world
    toothbrush.add_to private, world

Then, I can control who can do what, with what:

    wife.can!(:use, :hide, :throw_away, :in => private)
    wife.can!(:visit, :use, :hide, :throw_away, :in => private)
    buddy.can!(:use, :in => public)
    boss.can!(:visit, :in => public)

The permissions are arbitrary, but are best named with a verb. With permissions set, we can
query them:

Queries are based on the circle:

    buddy.can?(:see => private) -> false
    wife.can?(:see => private) -> true
    wife.can?(:throw_away, :in => private) -> true
    boss.can?(:use, :in => private) -> false

Object also has a some query methods:

    toothbrush.who_can_see -> [john, wife]
    tv.all_who_can(:use) -> [john, wife, bill]

    toothbrush.all_who_can(:use).include? wife -> true

You can also get all users in a circle, regardless of type

    private.users -> [john, wife]
    public.users -> [john, wife, bill, boss]

and all the objects in a circle, regardless of type:

    private.items -> [stapler, toothbrush]
    world.items -> [stapler, toothbrush, couch, tv]

# License

Copyright (c) 2010 [John W.P. Metta](http://johnmetta.com)

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.