retrieve_grid.rb

# coding: utf-8

def convert_path(path)
  path.gsub('/uploads/', '')
end

directory_path = "#{Rails.root}/tmp/grid"
FileUtils.mkdir_p directory_path + "/uploads/images"

grid = Mongo::GridFileSystem.new(Mongoid.database)
counter = 0

Image.all.each do |item|
	begin
		grid.open(convert_path(item.url), 'r') do |f|
			new_file = File.new(directory_path + item.url, "w+")
			new_file.puts(f.read.force_encoding('utf-8'))
			new_file.close
			counter = counter + 1
		end
	rescue Exception => e
		puts '-------------------------------------------'
		puts e.message
		puts "id: #{item.id}"
		puts '-------------------------------------------'
	end
end

puts '########################### Done #################################'
puts "   retrieved #{counter} images, total Image instances: #{Image.count}"
puts '##################################################################'