Build compose-able query objects by delaying query execution and delegating to the underlying `ActiveRecord::Relation` for everything else. #ruby #rails

_compose_query_objects.md

Compose-able Query Objects in Rails

Example usage:

old_accounts = Account.where("created_at < ?", 1.month.ago)
old_abandoned_trials = AbandonedTrialQuery.new(old_accounts)

old_abandoned_trials.find_each do |account|
  account.send_offer_for_support
end

Hat-tips:

I've been using this pattern for a while, but this particular example is a re-imagining of @brynary's Extract Query Objects pattern.

abandoned_trial_query.rb

require 'delegate'

class AbandonedTrialQuery < SimpleDelegator
  def initialize(relation = Account.scoped)
    super(relation.where(plan: nil, invites_count: 0))
  end
end

Nice, thanks for this example. Works a treat!

How is this better than just using a scope?

class Account < ActiveRecord::Base
  scope :abandoned_trials, where(plan: nil, invites_count: 0).where("created_at < ?", 1.month.ago)
end

Account.abandoned_trials.each(&:send_offer_for_support)

@rantler I'm not trying to make a value judgement here - as to it being better or worse than anything. As mentioned in the Gist description, this is simply another technique for slimming down fat ActiveRecord objects.

Five years later... I'm searching the Internets for alternative techniques and/or implementations. I've not found anything so simple. Is this still a Good Idea™ in Rails-land circa 2017 (on version 5.1)?