Module: ChronoModel::Patches::Preloader

Defined in:
lib/chrono_model/patches/preloader.rb

Overview

Patches ActiveRecord::Associations::Preloader to add support for temporal associations. This is tying itself to Rails internals and it is ugly :-(.

Defined Under Namespace

Modules: Association, ThroughAssociation

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#chronomodel_options ⇒ Object (readonly)

Returns the value of attribute chronomodel_options.



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# File 'lib/chrono_model/patches/preloader.rb', line 10

def chronomodel_options
  @chronomodel_options
end

Instance Method Details

#initialize(**options) ⇒ Object

We overwrite the initializer in order to pass the as_of_time parameter above in the build_preloader



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# File 'lib/chrono_model/patches/preloader.rb', line 15

def initialize(**options)
  @chronomodel_options = options.extract!(:as_of_time, :model)
  options[:scope] = chronomodel_scope(options[:scope]) if options.key?(:scope)

  if options.empty?
    super()
  else
    super(**options)
  end
end

#preload(records, associations, given_preload_scope = nil) ⇒ Object

Patches the AR Preloader (lib/active_record/associations/preloader.rb) in order to carry around the as_of_time of the original invocation.

  • The records are the parent records where the association is defined

  • The associations are the association names involved in preloading

  • The given_preload_scope is the preloading scope, that is used only in the :through association and it holds the intermediate records through which the final associated records are eventually fetched.

As the preload_scope is passed around to all the different incarnations of the preloader strategies, we are using it to pass around the as_of_time of the original query invocation, so that preloaded records are preloaded honoring the as_of_time.

The preload_scope is present only in through associations, but the preloader interfaces expect it to be always defined, for consistency.

For ‘:through` associations, the given_preload_scope is already a Relation, that already has the as_of_time getters and setters, so we use it directly.



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# File 'lib/chrono_model/patches/preloader.rb', line 47

def preload(records, associations, given_preload_scope = nil)
  super(records, associations, chronomodel_scope(given_preload_scope))
end