Hello World: uninitialized constant ApplicationController

Rails
1

Have the Wrox guide, but still having problems getting my hello world to
run (very frustrating! :wink: Installed latest InstantRails package for
Windows (XP). Thank you so much for helping!!

Dirk

After creating the project directories, I created my
\app\controllers\greeting_controller.rb file:

class GreetingController < ApplicationController
def greeting
end
end

Then put in my \app\views\greeting.rhtml page:

Greeting Page

Hello, this is my Greeting Page

After starting the project web app. in Mongrel and connecting here:
http://localhost:3000/greeting/greeting

I get the following error:

NameError in GreetingController#greeting

uninitialized constant ApplicationController

How is this base class initialized? I must be leaving something very
basic out,
Thanks for helping!

2

(cont.)

I am using mySQL and have configured the database.yml file to have all
adapter: mysql

Also, here is the full trace of the error message above:
C:/ruby/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:266:in
load_missing_constant' C:/ruby/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:453:inconst_missing’
C:/ruby/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:465:in
const_missing' app/controllers/greeting_controller.rb:1 C:/ruby/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:203:inload_without_new_constant_marking’
C:/ruby/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:203:in
load_file' C:/ruby/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:342:innew_constants_in’
C:/ruby/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:202:in
load_file' C:/ruby/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:94:inrequire_or_load’
C:/ruby/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:248:in
load_missing_constant' C:/ruby/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:453:inconst_missing’
C:/ruby/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:465:in
const_missing' C:/ruby/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/inflector.rb:257:inconstantize’
C:/ruby/ruby/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/core_ext/string/inflections.rb:148:in
constantize' C:/ruby/ruby/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/routing.rb:1426:inrecognize’
C:/ruby/ruby/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:170:in
handle_request' C:/ruby/ruby/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:115:indispatch’
C:/ruby/ruby/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:126:in
dispatch_cgi' C:/ruby/ruby/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/dispatcher.rb:9:indispatch’
C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/rails.rb:76:in
process' C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/rails.rb:74:insynchronize’
C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/rails.rb:74:in
process' C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:159:inprocess_client’
C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:158:in
each' C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:158:inprocess_client’
C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:285:in
run' C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:285:ininitialize’
C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:285:in
new' C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:285:inrun’
C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:268:in
initialize' C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:268:innew’
C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:268:in
run' C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/configurator.rb:282:inrun’
C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/configurator.rb:281:in
each' C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/configurator.rb:281:inrun’
C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/bin/mongrel_rails:128:in
run' C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/command.rb:212:inrun’
C:/ruby/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/bin/mongrel_rails:281
C:/ruby/ruby/bin/mongrel_rails:19:in `load’
C:/ruby/ruby/bin/mongrel_rails:19

3

When you created the project, a file named “application.rb” should
have been created in app/controllers. This file defines the
ApplicationController class.

Aaron

4

Aaron wrote:

When you created the project, a file named “application.rb” should
have been created in app/controllers. This file defines the
ApplicationController class.

Aaron

Thank you so much! Yes, a silly error, I have just confirmed and it now
works. It’s not yet so well documented in Wrox “Beginning Ruby on
Rails”

Thank you again,
Dirk