Introduced Lotus::Action::Params#get

[jodosha]

What

Introduced Lotus::Action::Params#get as a safe way to access (nested) attributes.

Why?

1. Developers can safely access nested params without worrying of NoMethodErrors that can be caused by the subscriber notation. Eg params[:address][:street], if :address isn't sent, the action will blow up. The lack of this new suggested API (#get) will force developers to write defensive code to access nested attributes.
2. This serves as supporting feature for Lotus::Helpers' form helper. In case of param validation failures, a form should be able to be rendered again and keep the current values.

Usage

require 'lotus/controller'

module Deliveries
  class Create
    include Lotus::Action

    params do
      param :customer_name
      param :address do
        param :city
      end
    end

    def call(params)
      params.get('customer_name')   # => "Luca"
      params.get('uknown')          # => nil

      params.get('address.city')    # => "Rome"
      params.get('address.unknown') # => nil

      params.get(nil)               # => nil
    end
  end
end

[coveralls]

Coverage increased (+0.01%) to 99.02% when pulling e9e8d87 on params-get into 1bbd4f1 on master.

[coveralls]

Coverage increased (+0.01%) to 99.02% when pulling e9e8d87 on params-get into 1bbd4f1 on master.

[coveralls]

Coverage increased (+0.01%) to 99.02% when pulling e9e8d87 on params-get into 1bbd4f1 on master.

[coveralls]

Coverage increased (+0.01%) to 99.02% when pulling 95e5246 on params-get into 1bbd4f1 on master.

[coveralls]

Coverage increased (+0.01%) to 99.02% when pulling cf2a1cb on params-get into 1bbd4f1 on master.

[vyper]

Why we only use string for get a key?

I ❤️ this approach...

params.get('customer_name')  # => "Luca"
params.get(:customer_name)   # => "Luca"

[runlevel5]

@vyper hash is nice but it does not represent the nested attributes very well. For that very reason, I think we should stick to string.

[runlevel5]

@jodosha 👍