README.md
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ActionParameter
===============
ActionParameter helps you move all your parameter's logic into it's own class. This way you'll keep your controllers dry and they would be easier to test.
Before
------
```ruby
# app/controllers/users_controllers.rb
class UsersController < ActionController::Base
def create
User.create(user_params)
end
private
def user_params
params.require(:user).permit(:name, :age)
end
end
```
After
-----
```ruby
# app/controllers/users_controllers.rb
class UsersController < ActionController::Base
def create
# It automatically deduces which Parameters class from Controller's name
User.create(permitted_params.permit)
end
end
```
```ruby
# app/parameters/user_parameters.rb
class UserParameters < ActionParameter::Base
def permit
params.require(:user).permit(:name, :age)
end
end
```
Install
-------
ActionParameter works with Rails 3.0 onwards and Ruby 1.9.3 onwards. You can add it to your Gemfile with:
```ruby
gem 'action_parameter'
```
Run the bundle command to install it.
Usage
-----
####Generator
```ruby
rails generate parameters [MODEL_NAME]
```
Will create **app/parameters/[model_name]_parameters.rb**.
####Controller Helpers
- **permitted_params:** Returns an ActionParameter instance.
```ruby
permitted_params(options={})
```
#####Options Hash
* **options** - Hash with one valid key: **:class**.
* **options[:class]** - Symbol value with the name of the Parameters class you want to use.
#####Example 1
```ruby
# app/controllers/people_controllers.rb
class PeopleController < ActionController::Base
def create
Person.create(permitted_params.permit) # This will call to PersonParameters' permit method
end
end
```
```ruby
# app/parameters/person_parameters.rb
class PersonParameters < ActionParameter::Base
def permit
params.require(:person).permit(:name, :age)
end
end
```
#####Example 2
```ruby
# app/controllers/people_controllers.rb
class PeopleController < ActionController::Base
def create
Person.create(permitted_params(class: :user).sign_up) # This will call to UserParameters' sign_up method
end
end
```
```ruby
# app/parameters/user_parameters.rb
class UserParameters < ActionParameter::Base
def sign_up
params.require(:person).permit(:name, :age)
end
end
```
####Parameter Class Helpers
#####Default Helpers
- **params:** Returns params from the current controller request which instantiated the Parameter class.
- **controller_name:** Returns the controller's name from which the Parameter class was instantiated.
- **action_name:** Returns the action's name from the controller from which the Parameter class was instantiated.
#####Creating New Helpers
If you want to create new helper methods for your parameters class, just call **locals** method over **permitted_params**. Let say you want to make **@current_user** available for the UserParameter's class under the **user** method, then you'll need to use the **locals** method to tell the UserParameters class to create a new helper that returns **@current_user**.
```ruby
permitted_params(class: :user).locals( user: @current_user,
another_helper: @value )
```
This will create **user** and **another_helper** methods and they will be available in UserParameters class.
#####Example
```ruby
# app/controllers/users_controllers.rb
class UsersController < ActionController::Base
def create
User.create(permitted_params.locals(user: @current_user).permit) # This will call to UserParameters' permit method
end
end
```
```ruby
# app/parameters/user_parameters.rb
class UserParameters < ActionParameter::Base
def permit
if user.admin?
params.require(:person).permit(:name, :age, :admin)
else
params.require(:person).permit(:name, :age)
end
end
end
```
RSpec
-----
This example shows how to test using RSpec.
Theses tests require your **test.rb** configured to **config.action_controller.action_on_unpermitted_parameters = :raise**.
```ruby
# spec/parameters/user_parameters_spec.rb
require "spec_helper"
describe UserParameters do
describe ".permit" do
describe "when permitted parameters" do
it "returns the cleaned parameters" do
user_params = { first_name: "John", last_name: "Doe" }
params = ActionController::Parameters.new(user: user_params)
permitted_params = UserParameters.new(params).permit
expect(permitted_params).to eq user_params.with_indifferent_access
end
end
describe "when unpermitted parameters" do
it "raises error" do
user_params = { foo: "bar" }
params = ActionController::Parameters.new(user: user_params)
expect{ UserParameters.new(params).permit }.
to raise_error(ActionController::UnpermittedParameters)
end
end
end
end
```