ActiveModel Series ActiveModel:API

What is ActiveModel::API?

ActiveModel::API

ActiveModel::API adds the ability for a ruby class to work with Action Pack and Action View right out of the box.

When including ActiveModel::API we get some features of ActiveRecord:

• model name introspection
• conversions
• translations
• validations

For example

require 'active_model'
class Person
  include ActiveModel::API
  attr_accessor :name, :email 
  validates :name, :email, presence: true
end
person = Person.new(name: '', email: '')
p person.valid? 
#=> false

Above you can see that i am using the method validates to validate the attributes name and email.

Note: You should have rails gem installed in your system and you need to require active_model. Also you can see that to use the validates method i have included a active model’s module. include ActiveModel::API

So what is happening in the code above is, I created the object of class Person which has included a module ActiveModel::API.

Therefore, we can apply .valid? to Person’s object.

You may also note that:

ActiveModel::API gives us the ability to initialize an object with a hash of attributes, much like any Active Record object.

For example:

require 'active_model'
class Person
 include ActiveModel::API
 attr_accessor :name, :email
validates :name, :email, presence: true
end
# initializing an object with a hash of arguments
person = Person.new(name: 'pratik', email: 'pratik@rubyonrails.com')
p person.name
#=> 'pratik'

The documentation says:

Any class that includes ActiveModel::API can be used with form_with, render and any other Action View helper methods, just like Active Record objects.

Please refer to official documentation for more information

Thanks for giving it a read :)

Happy coding :)