Where do I 'require' a gem?

I'm using the login_system gem which works fine on my dev. environment (RadRails / webbrick). Also my hosting company (A2) installed the same GEM. But when I try to login on the production server, I get:

NoMethodError in AccountController#login

undefined method `redirect_back_or_default' for #<AccountController:0x2a96ffa088>

Does there need to be a require somewhere?

Thanks for your feedback.

I added require_gem 'login_generator' to the environment.rb, but no dice. How would I determine what other dependencies are required?

When the gem was installed in my environment it created the file login_system.rb in my lib directory. This defines a module LoginSystem which includes the method redirect_back_or_default.

Does this somehow need to be included? Still don't understand why it complains in production mode but is fine in dev. mode.

You have to “include” the LoginSystem in ApplicationController:

class ApplicationController < ActionController::Base include LoginSystem … end


No, require_gem is deprecated and should not be used unless you need to require a specific version of a gem. It will be removed in subsequent rubygems releases. Don't use it because it is misleading and doesn't really do what it seems like it should do. TO require an installed gem you only need to do this:

require 'rubygems' require 'gemname'

And rails already requires rubygems unless you have rails frozen in vendor.


I just wanted to give everybody an update. I was completely frustrated with this gem. The hosting company (A2) gave me their response: "Unfortunately, it is beyond the scope of our support to debug applications/code for customers"

Anyway, I cancelled my account with them and moved over to DreamHost. Followed their very through Wiki instructions and it now works perfectly.


i suppose on top of this you could create a file in your /config/initializers/ directory to load all the gems your app needs; making things a little more neat.

haven't tried myself but should be possible rather than sticking it into your environment.rb file all the time