How to Debug in Rails
Every developers need debuggers now and then. I have been using ruby-debug for a while now.
You can check whether you have ruby-debug installed:
gem list ruby-debug
If you do not have ruby-debug installed, you can run the following command:
gem install ruby-debug
I have been using Mongrel for my development. To enable debugging, you should start your server with –debug option:
ruby script/server –debug
To stop at a certain point in your code, all you need to do is to add a ‘debugger’ line:
def edit
@task = Task.find(params[:id])
debugger
current_user_id = find_current_user_id()
end
Once your application reach the ‘debugger’ line, the server window will turn into:
(rdb:10)
To check for a variable value, type:
pp @task
You can explore other commands easily by typing ‘help’.
(rdb:10) help
ruby-debug help v0.10.1
Type ‘help <command-name>’ for help on a specific command
Available commands:
backtrace delete enable help next quit show trace
break disable eval info p reload source undisplay
.
.
Happy debugging! 