Example Rollcall plugin for Corral

account_callbacks.rb

require 'rest_client'
require 'uri'
require 'account'

# this is basically a monkey patch of Rollcall's Account class...
# it's one of those things you would never see in Java, because you can't really
# modify a class during runtime
Account.class_eval do

    # here we tell the Account class to execute different methods before
    # creating/updating/destroying a record
    before_create :create_account_in_corral, :if => proc{ !login.blank? && !password.blank? }
    before_update :update_account_in_corral, :if => proc{ !login.blank? && !password.blank? }
    before_destroy :delete_account_in_corral
  
    # this gets called prior to the record actually being committed to the database during
    # the "validation" step... one of the callbacks we refer to above might have encountered
    # an error and stored it under the @corral_error member variable. We check for it and
    # add it to the Account's list of errors. This will prevent the account from being saved,
    # and the user or web service client will see an error message instead.
    validate do
      self.errors[:base] << @corral_error if @corral_error
    end


    def create_account_in_corral
      # do the stuff you need to do to create the account in Corral.
      # if there's an error, put it (the string error message) in @corral_error
    end

    def update_account_in_corral
    end

    def destroy_account_in_corral
    end
  end
end

rollcall-corral.rb

# this is the file that makes the whole thing into a Rails plugin (a "Railtie")
# one of the things we do here is define the kinds of config options you can
# set for the plugin
module RollcallCorral
  class Railtie < Rails::Railtie
    config.corral = ActiveSupport::OrderedOptions.new

    initializer 'corral.initialize' do |app|
      # check if the option was given
      if config.corral.some_config_option
        # hold on to it as a constant (there are better ways to do it, but this is simpler
        RollcallCorall::SOME_CONFIG_OPTION = config.corral.some_config_option
      end
      
      # load the account_callbacks.rb monkeypatch file when the plugin is initialized
      require 'account_callbacks'
    end
  end
end

# the config options are set either in Rollcall's config/environments/*.rb files, or in 
# config/application.rb (if you want the same config for all environments