This is a really short, yet essential, introduction as to how to use the debugger in rails. It is assumed that you have a console showing you the mongrel server output and you know at what line your code fails. Also, you should have 'ruby-debug' installed on your machine (do a 'gem install ruby-debug', if you don't). For simplicity, assume there is an error on line 21 in file 'rubrics_controller'. Here is what you would do:
-
Add the word 'debugger' on line 20 (one line prior to the erroneous line) in 'rubrics_controller.rb'
-
Reload the page giving you the error (it will stop executing right at the line you added 'debugger')
-
Go to the console window where your mongrel server output is printed and type 'irb'
-
That's it! You have a debugging console ready and you are save typing your ~ debugging commands, now (see the [[Rails debugging guide | http://guides.rubyonrails.org/debugging_rails_applications.html]] for more information)
-
Once you have finished debugging, type 'quit', hit return, remove the line ~ 'debugger' and type 'continue' to resume your mongrel server.
Enjoy, debugging!