It’s crunch time here at Launch Academy. Our projects have to be up and running with databases that will, you know, actually show off the functionality that we’ve worked 10 weeks to achieve. This means seeding, and depending on the complexity of our models and associations, seeding can go from a simple one-line script to, well, something like this:
module Seeders
module Lessons
class << self
def seed
Lesson.destroy_all
lessons = []
base_path = 'db/seed_data'
Dir.glob(Rails.root.join(base_path, 'lessons', '*.yml')) do |file|
lesson = YAML.load_file(file)
this_lesson = Lesson.create(title: lesson['title'], summary: lesson['summary'])
lessons << this_lesson
lesson['activities'].each_with_index do |activity, index|
completable = []
if activity['type'] == 'Assignment'
completable = Assignment.create do |assignment|
assignment.title = activity['title']
assignment.summary = activity['summary']
assignment.instructions = activity['instructions']
assignment.url = activity['url']
assignment.assignment_type = activity['assignment_type']
end
elsif activity['type'] == 'Challenge'
completable = Challenge.create do |challenge|
challenge.title = activity['title']
end
activity['cards'].each do |card|
new_card = Card.create do |c|
c.title = card['title']
c.instructions = card['instructions']
c.problem = card['problem']
c.solution_type = card['solution_type']
c.snippet = card['snippet'] if card['snippet'].present?
end
card['solutions'].each do |solution|
if card['solution_type'] == 'string'
sol = new_card.solution_strings.create do |solution_string|
solution_string.regex = solution['regex']
solution_string.canonical = true if solution['canonical']
end
elsif card['solution_type'] == 'position'
sol = new_card.solution_positions.create do |solution_position|
solution_position.start_position = solution['start_position']
solution_position.end_position = solution['end_position']
end
end
completable.cards << new_card
end
end
end
Activity.create do |lesson_activity|
lesson_activity.completable = completable
lesson_activity.lesson = this_lesson
lesson_activity.position = index + 1
end
end
end
lessons
end
end
end
end
This is the seeder for my project: Memworks. A major part of the app is lessons, each of which has assignments and challenges. There’s a lot of content, and my first approach was to just shove it all in big Ruby objects and require
the relevant source files. I decided to shift to a YAML approach when the Ruby hashes became so large as to become unwieldy.