BitAttrs

BitAttrs allows to store a set of boolean values in one field.

Simple and easy to use
Has no additional dependencies, like ActiveRecord
Works well with ActiveRecord, DataMapper, Virtus or POROs
Has convenient search scopes for ActiveRecord and DataMapper

Installation

Add this line to your application's Gemfile:

gem 'bit_attrs'

And then execute:

$ bundle

Or install it yourself as:

$ gem install bit_attrs

Usage

BitAttrs has similar to Rails 4 enums syntax:

class User < ActiveRecord::Base
  include BitAttrs
  bitset roles: [:admin, :user, :guest]
end
```

In this case, BitAttrs will expect ```roles_mask``` field to actually save roles in:

```ruby
#<User id: 1, name: 'test user', email: "[email protected]", roles_mask: 2>
```

You can freely add new attributes to the end of the list without changing already existing records:

````ruby
class User < ActiveRecord::Base
  include BitAttrs
  bitset roles: [:admin, :user, :guest, :developer]
end
```

Similarly to Rails enums, if you want to delete some of the attributes, you might want to use hash syntax, where keys are attribute names and values are indexes:

````ruby
class User < ActiveRecord::Base
  include BitAttrs
  bitset roles: { admin: 0, user: 1, developer: 3 }
end
```

Attributes can be accessed on the instance level or through the ```roles``` method:

```ruby
> user
=> #<User id: 1, name: 'test user', email: "[email protected]", roles_mask: 2>

> user.user?
=> true

> user.roles
=> { admin: false, user: true, guest: false }
```

Update all attributes (with overwriting):

```ruby
> user.roles
=> { admin: false, user: true, guest: false }

> user.update(roles: { guest: true }) && user.roles
=> { admin: false, user: false, guest: true }
```

Update single attribute:

```ruby
> user.roles
=> { admin: false, user: true, guest: false }

> user.admin = true
=> { admin: true, user: true, guest: false }
```

### Scopes

Considering the example above, BitAttrs will create following search scopes:

```
* User.with_roles
* User.without_roles
```

Example:

```ruby
> User.with_roles(:user)
=> all users which have role :user set to true
> User.with_roles(:admin, :user).without_roles(:developer)
=> all users which have following roles set: { admin: true, user: true, developer: false }
```

## Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/rsamoilov/bit_attrs. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [Contributor Covenant](http://contributor-covenant.org) code of conduct.


## License

The gem is available as open source under the terms of the [MIT License](http://opensource.org/licenses/MIT).