README.md
# ContextValidations #
[](http://travis-ci.org/dockyard/context_validations)
[](https://gemnasium.com/dockyard/context_validations)
[](https://codeclimate.com/github/dockyard/context_validations)
Context based validations for model instances.
## Looking for help? ##
If it is a bug [please open an issue on GitHub](https://github.com/dockyard/context_validations/issues).
## Installation ##
In your `Gemfile`
```ruby
gem 'context_validations'
```
You can either mixin the modules on a case-by-case basis or make the
changes global:
### Case-by-case ###
```ruby
# model
class User < ActiveModel::Base
include ContextValidations::Model
end
# controller
class UsersController < ApplicationController
include ContextValidations::Controller
end
```
### Global ###
Create an initializer: `config/initializers/context_validations.rb`
```ruby
class ActiveRecord::Base
include ContextValidations::Model
end
class ActionController::Base
include ContextValidations::Controller
end
```
## Usage ##
```ruby
class UserController < ApplicationController
include ContextValidations::Controller
def create
@user = User.new(user_params)
@user.validations = validations(:create)
if @user.save
# happy path
else
# sad path
end
end
private
def create_validations
validates :password, :presence => true
end
def base_validations
validates :first_name, :last_name, :presence => true
validates :password, :confirmation => true
validates :email, :uniqueness => true, :format => EmailFormat
end
end
class User < ActiveRecord::Base
include ContextValidations::Model
end
```
### Controllers ###
In the above example we just call `validations` and pass the context. We
set the result to `#validations=` on the model.
While this does introduce some complexity into our controllers it frees
us from the mental gymnastics of conditional validators and state flags.
The corresponding `#{context}_validations` method, in this case
`create_validations` defines the validations that will be used. Call the
`#validates` method just like you would in model validations, the API is
identical.
A `#base_validations` method is always called prior to
`#{context}_validations` that will allow you to group together common
validations. The result of these methods appends onto a `@validations`
array.
If you are using `Ruby 2.0+` you can use implicit contexts:
```ruby
def create
@user = User.new(user_params)
# Notice we are only calling the #validations method and not passing
# context. In this example the context is derived from the calling
# method `create`
@user.validations = validations
end
private
def create_validations
...
end
```
### Models ###
When the `ContextValidations::Model` module is mixed into the model all
of the validation callbacks are removed from that model.
Because we are setting the validations on the instance you should not
use `ActiveRecord::Base.create` as we do not want to allow the
validations to be set via mass-assignment. This does introduce an extra
step in some places but it shouldn't be that big of a deal.
## Testing ##
Currently only `MiniTest` is supported. We are open to pull requests for supporting additional test frameworks but we only work with `MiniTest`
so we probably won't go out of the way to support something we're not using.
We highly recommend using [ValidAttribute](https://github.com/bcardarella/valid_attribute) to test your validations. The following example is done using
`ValidAttribute`.
### MiniTest ###
In `/test/test_helper.rb`:
```ruby
require 'context_validations/minitest'
```
You are given access to a `#validations_for(:action_name)` method. You should pass the action in your
controller that is the context of the validations and use the `#validations=` setter on the model.
This is a common example of how to test:
```ruby
require 'test_helper'
describe UserController do
context 'create' do
subject { User.new(:password => 'password', :validations => validations_for(:create)) }
it { must have_valid(:name).when('Brian Cardarella') }
it { wont have_valid(:name).when(nil, '') }
end
end
```
## ClientSideValidations Support ##
The [ClientSideValidations](https://github.com/bcardarella/client_side_validations) gem is fully supported.
## Authors ##
* [Brian Cardarella](http://twitter.com/bcardarella)
[We are very thankful for the many contributors](https://github.com/dockyard/context_validations/graphs/contributors)
## Versioning ##
This gem follows [Semantic Versioning](http://semver.org)
## Want to help? ##
Please do! We are always looking to improve this gem. Please see our
[Contribution Guidelines](https://github.com/dockyard/context_validations/blob/master/CONTRIBUTING.md)
on how to properly submit issues and pull requests.
## Legal ##
[DockYard](http://dockyard.com), LLC © 2013
[@dockyard](http://twitter.com/dockyard)
[Licensed under the MIT license](http://www.opensource.org/licenses/mit-license.php)