Halumi

One of the cool patterns in Rails development are query objects. They are essantialy service objects returning a ActiveRecord Relation. Using them results in less code cluttering your controllers and models. Plus you can easily unit test each of your queries.

This Gem adds simple DSL allowing you to build query objects and than combining them into one query that will be executed against your database

Example usage

Define your 'super' query combining 3 subqueries

class ArticlesQuery < Halumi::Query
  model Article

  merge PaginationQuery
  merge PublishedArticlesQuery
  merge OrderArticlesQuery
end

class PaginationQuery < Halumi::Query
  param :per_page
  param :page

  def execute
    relation.page(page).per(per_page)
  end
end

class PublishedArticlesQuery
  def execute
    relation.where(published: true)
  end
end

class OrderArticlesQuery < Halumi::Query
  def execute
    relation.order(:created_at)
  end
end

Run your query

This will return published articles, paginated and sorted by creation time

params = { page: 2, per_page: 10 }

ArticlesQuery.new(params).call

Optional integration with Dry::Types

Params with dry type specified behave like they would be sanatized by it. If a a type would rise an error, for example in case of strict types, the error will be rescued and query execution will be terminated

class PaginationQuery < Halumi::Query
  param :per_page, Types::Strict::Integer
  param :page, Types::Strict::Integer

  def execute
    relation.page(page).per(per_page)
  end
end