Strange behavior between rails and irb

Question

If I drop in to irb and do require 'atom' I can successfully include the gem but if I try to include it in my controller in rails I get no such file to load -- atom when I visit the page in the browser. What's going on here?

Here's the complete stack trace:

C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require'
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:521:in `new_constants_in'
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require'
D:/Build/Contactly/app/controllers/contacts_controller.rb:3
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:380:in `load_without_new_constant_marking'
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:380:in `load_file'
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:521:in `new_constants_in'
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:379:in `load_file'
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:259:in `require_or_load'
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:425:in `load_missing_constant'
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:80:in `const_missing'
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:92:in `const_missing'
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/inflector.rb:361:in `constantize'
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/inflector.rb:360:in `each'
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/inflector.rb:360:in `constantize'
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/core_ext/string/inflections.rb:162:in `constantize'
C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.5/lib/action_controller/routing/route_set.rb:443:in `recognize'
C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.5/lib/action_controller/routing/route_set.rb:436:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.5/lib/action_controller/dispatcher.rb:87:in `dispatch'
C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.5/lib/action_controller/dispatcher.rb:121:in `_call'
C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.5/lib/action_controller/dispatcher.rb:130:in `build_middleware_stack'
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/query_cache.rb:29:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/query_cache.rb:29:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/query_cache.rb:34:in `cache'
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/query_cache.rb:9:in `cache'
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/query_cache.rb:28:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/connection_pool.rb:361:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.5/lib/action_controller/string_coercion.rb:25:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/head.rb:9:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/methodoverride.rb:24:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.5/lib/action_controller/params_parser.rb:15:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.5/lib/action_controller/session/cookie_store.rb:93:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.5/lib/action_controller/failsafe.rb:26:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/lock.rb:11:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/lock.rb:11:in `synchronize'
C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/lock.rb:11:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.5/lib/action_controller/dispatcher.rb:114:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.5/lib/action_controller/reloader.rb:34:in `run'
C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.5/lib/action_controller/dispatcher.rb:108:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/rails/rack/static.rb:31:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/urlmap.rb:46:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/urlmap.rb:40:in `each'
C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/urlmap.rb:40:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/rails/rack/log_tailer.rb:17:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/content_length.rb:13:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/handler/webrick.rb:50:in `service'
C:/Ruby/lib/ruby/1.8/webrick/httpserver.rb:104:in `service'
C:/Ruby/lib/ruby/1.8/webrick/httpserver.rb:65:in `run'
C:/Ruby/lib/ruby/1.8/webrick/server.rb:173:in `start_thread'
C:/Ruby/lib/ruby/1.8/webrick/server.rb:162:in `start'
C:/Ruby/lib/ruby/1.8/webrick/server.rb:162:in `start_thread'
C:/Ruby/lib/ruby/1.8/webrick/server.rb:95:in `start'
C:/Ruby/lib/ruby/1.8/webrick/server.rb:92:in `each'
C:/Ruby/lib/ruby/1.8/webrick/server.rb:92:in `start'
C:/Ruby/lib/ruby/1.8/webrick/server.rb:23:in `start'
C:/Ruby/lib/ruby/1.8/webrick/server.rb:82:in `start'
C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.1/lib/rack/handler/webrick.rb:14:in `run'
C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/commands/server.rb:111
C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
script/server:3

Answer 1

irb is the interactive Ruby shell which is not rails. when you do gem install you are making it available for your installed version of Ruby, however Rails is slightly different. Rails only interacts with the gems you have listed in your Gemfile. Assuming you are using Rails 3, you would edit your Gemfile to include to the gem

gem 'atom'

save the file and then run

bundle install

then, once you run rails s that gem is available to your rails application. For future note, if you want to try out how something will work in a rails context, instead of invoking irb, invoke rails console or ./script/rails console (depending on which version of rails you are using).

Answer 2

Did you include it in your gemfile?