Run code on the start of a rails server

Question

When the Ruby on Rails application starts I want it to run a block of code so that the database is filled with the required data. I've been searching for hours for a solution, none of the given solutions that I found worked. The following is the solution that I implemented.

In application.rb I placed the following block of code:

def fill_db
    redirect_to url_for(:controller => :item, :action => :init)
    self.delay(:run_at => 10.minute.from_now).fill_db
end

config.after_initialize do
    redirect_to url_for(:controller => :item, :action => :init)
    fill_db
end

I tried to implement dozens of other variants of this but none of them worked.

The error I get is this:

C:\xampp\htdocs\dev-ruby\untitled1>rails s
=> Booting WEBrick
=> Rails 4.2.6 application starting in development on http://localhost:3000
=> Run `rails server -h` for more startup options
=> Ctrl-C to shutdown server
Exiting
C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/railtie.rb:196:in `method_missing': undefined method `url_for' for Untitled1::Application:Class (NoMethodError)
        from C:/xampp/htdocs/dev-ruby/untitled1/config/application.rb:40:in `block in <class:Application>'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.2.6/lib/active_support/lazy_load_hooks.rb:36:in `call'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.2.6/lib/active_support/lazy_load_hooks.rb:36:in `execute_hook'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.2.6/lib/active_support/lazy_load_hooks.rb:45:in `block in run_load_hooks'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.2.6/lib/active_support/lazy_load_hooks.rb:44:in `each'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.2.6/lib/active_support/lazy_load_hooks.rb:44:in `run_load_hooks'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/application/finisher.rb:62:in `block in <module:Finisher>'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/initializable.rb:30:in `instance_exec'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/initializable.rb:30:in `run'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/initializable.rb:55:in `block in run_initializers'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/2.1.0/tsort.rb:226:in `block in tsort_each'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/2.1.0/tsort.rb:348:in `block (2 levels) in each_strongly_connected_component'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/2.1.0/tsort.rb:427:in `each_strongly_connected_component_from'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/2.1.0/tsort.rb:347:in `block in each_strongly_connected_component'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/2.1.0/tsort.rb:345:in `each'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/2.1.0/tsort.rb:345:in `call'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/2.1.0/tsort.rb:345:in `each_strongly_connected_component'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/2.1.0/tsort.rb:224:in `tsort_each'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/2.1.0/tsort.rb:205:in `tsort_each'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/initializable.rb:54:in `run_initializers'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/application.rb:352:in `initialize!'
        from C:/xampp/htdocs/dev-ruby/untitled1/config/environment.rb:5:in `<top (required)>'
        from C:/xampp/htdocs/dev-ruby/untitled1/config.ru:3:in `require'
        from C:/xampp/htdocs/dev-ruby/untitled1/config.ru:3:in `block in <main>'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/rack-1.6.4/lib/rack/builder.rb:55:in `instance_eval'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/rack-1.6.4/lib/rack/builder.rb:55:in `initialize'
        from C:/xampp/htdocs/dev-ruby/untitled1/config.ru:in `new'
        from C:/xampp/htdocs/dev-ruby/untitled1/config.ru:in `<main>'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/rack-1.6.4/lib/rack/builder.rb:49:in `eval'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/rack-1.6.4/lib/rack/builder.rb:49:in `new_from_string'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/rack-1.6.4/lib/rack/builder.rb:40:in `parse_file'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/rack-1.6.4/lib/rack/server.rb:299:in `build_app_and_options_from_config'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/rack-1.6.4/lib/rack/server.rb:208:in `app'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands/server.rb:61:in `app'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/rack-1.6.4/lib/rack/server.rb:336:in `wrapped_app'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands/server.rb:139:in `log_to_stdout'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands/server.rb:78:in `start'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands/commands_tasks.rb:80:in `block in server'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands/commands_tasks.rb:75:in `tap'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands/commands_tasks.rb:75:in `server'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
        from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.2.6/lib/rails/commands.rb:17:in `<top (required)>'
        from bin/rails:4:in `require'
        from bin/rails:4:in `<main>'

The same code works in a controller, but then it's not executed at the start of the rails server.

Answer 1

You cannot use redirect_to inside application.rb. This is part of the ActionController classes. Here are two things that you can do instead

1) Implement db:seed - there is a db/seed.rb that you can use to populate initial database values. After you deploy the code just run bin/rails db:seed to run this task that will fill out the database

or

2) Add before_action to applicationController

class ApplicationController < ActionController::Base
  before_action :fill_db
end

To prevent from executing this method add conditional like unless populated?

Hope it helps