Gorillib::Model #field usage

field_usage.rb

require 'gorillib/model'

# In this first example, we have a User that will have a first and last name, and a synthetic secret_id.
# The secret_id could be provided, but if it is not, we want to supply a default based on the names.
# We need access to the other fields being received, so we used a delayed default:
class User
  include Gorillib::Model
  
  field :first_name, String
  field :last_name,  String
  field :secret_id,  String, default: ->(){ Digest::MD5.hexdigest(first_name + last_name) }
  
end
# The above allows this to work:
user = User.receive(first_name: 'Bob', last_name: 'Barker', secret_id: '45655ef5b6496fca9df96fbae6398e0a')
user.secret_id
#=> "45655ef5b6496fca9df96fbae6398e0a"

# It also supplies a default, only created when #secret_id is called:
user = User.receive(first_name: 'Bob', last_name: 'Barker')
user.secret_id
#=> "45655ef5b6496fca9df96fbae6398e0a"

# If you would like to receive a field in a particular way, perhaps to do some light pre-processing,
# you can override the receive_<field_name> method
class User
  include Gorillib::Model
  
  field :first_name, String
  field :last_name,  String
  
  def receive_last_name param
    normalized = param.downcase.slice(0..7)
    write_attribute(normalized)
  end 
  
end 

# In the above case, every last_name receieved will be nomalized. The #write_attribute method is the hook
# Gorillib provides for setting the field in question.
u = User.receive(first_name: 'Arnold', last_name: 'Schwarzenegger')
u.last_name
#=> "schwarze"

# Gotchas:
# The #receive method expects a Hash to be provided. Don't try to receive anything else.
#
# If you call #receive with a hash that contains keys that are not defined as fields,
# they will be accessible via the @_extra_attributes instance variable.
# No guarantees or sanitization happens to the extra attributes; they are stored as-is.
user = User.receive(foo: 'bar', baz: 'qux')
user.instance_variable_get('@_extra_attributes')
#=> { :foo => "bar", :baz => "qux" }
#
# When #receive is called with a key pointing to nil, then the field is set to nil.
# Note: this will NOT assign default values.
user = User.receive(secret_id: nil)
user.secret_id
#=> nil