Rails 5: Dump Rails db to fixtures

db_fixtures_dump.rake

# Original from http://snippets.dzone.com/posts/show/4468 by MichaelBoutros
#
# Optimized version which uses to_yaml for content creation and checks
# that models are ActiveRecord::Base models before trying to fetch
# them from database.
namespace :db do
  namespace :fixtures do
    desc 'Dumps all models into fixtures.'
    task dump: :environment do
      models = Dir.glob(Rails.root + 'app/models/**.rb').map do |s|
        Pathname.new(s).basename.to_s.gsub(/\.rb$/,'').camelize
      end

      # excludes models
      excludes = %w(ApplicationRecord)

      puts "Found models: " + models.join(', ')

      models.reject { |m| m.in?(excludes) }.each do |m|
        model = m.constantize
        next unless model.ancestors.include?(ActiveRecord::Base)

        puts "Dumping model: " + m
        entries = model.order(id: :asc).all

        model_file = "#{Rails.root}/test/fixtures/#{m.underscore.pluralize}.yml"
        File.open(model_file, 'w') do |f|
          entries.each do |a|
            attrs = {}
            a.attributes.each do |k, v|
              next if v.blank?

              mm = k.match(/^(.*)_id$/)
              if mm
                attrs[mm[1]] = "#{mm[1]}_#{v}"
              elsif v.kind_of?(ActiveSupport::TimeWithZone)
                attrs[k] = v.to_s
              else
                attrs[k] = v
              end
            end

            key = m.underscore + '_' + attrs["id"].to_s
            attrs.delete("id")

            output = { key => attrs }
            f << output.to_yaml.gsub(/^--- \n/,'') + "\n"
          end
        end
      end
    end
  end
end