Rails Support
Rails plugin is implemented in a separate dry-initializer-rails gem.
It provides coercion of assigned values to corresponding ActiveRecord instances.
Base Example
Add the :model setting to param or option:
require 'dry-initializer-rails'
class CreateOrder
extend Dry::Initializer
# Params and options
param :customer, model: 'Customer' # use either a name
option :product, model: Product # or a class
def call
Order.create customer: customer, product: product
end
end
Now you can assign values as pre-initialized model instances:
customer = Customer.find(1)
product = Product.find(2)
order = CreateOrder.new(customer, product: product).call
order.customer # => <Customer @id=1 ...>
order.product # => <Product @id=2 ...>
...or their ids:
order = CreateOrder.new(1, product: 2).call
order.customer # => <Customer @id=1 ...>
order.product # => <Product @id=2 ...>
The instance is envoked using method find_by(id: ...).
With wrong ids nil values are assigned to corresponding params and options:
order = CreateOrder.new(0, product: 0).call
order.customer # => nil
order.product # => nil
Custom Keys
You can specify custom key for searching model instance:
require 'dry-initializer-rails'
class CreateOrder
extend Dry::Initializer
param :customer, model: 'User', find_by: 'name'
option :product, model: Item, find_by: :name
end
This time you can send names (not ids) to the initializer:
order = CreateOrder.new('Andrew', product: 'the_thing_no_123').call
order.customer # => <User @name='Andrew' ...>
order.product # => <Item @name='the_thing_no_123' ...>
Container Syntax
If you prefer container syntax, extend plugin inside the block:
require 'dry-initializer-rails'
class CreateOrder
include Dry::Initializer.define -> do
# ... params/options declarations
end
end
Types vs Models
Type constraints are checked before the coercion.
When mixing :type and :model settings for the same param/option, you should use sum types that accept both model instances and their attributes.