readme.md

Using Exceptions to manage control flow in Rails Controllers

This is an example from the blog post: http://www.ngauthier.com/2011/09/using-exceptions-to-manage-control-flow.html.

Please fork it and show me what you would do!

twitter_reverse_auth_controller.rb

class TwitterReverseAuthController < ApplicationController
  class OauthCredential < Struct.new(:token, :secret)
  end

  class TwitterAuthenticator
    Error = Class.new(StandardError)

    def initialize(options)
      @options = options
    end

    def authenticate_device
      user.devices.find_or_create_by_token!({
        :token => oauth_credential.token,
        :description => @options[:description]
      })
    end

  private

    def user
      @user ||= User.find_for_oauth!(fetch_option(:screen_name), oauth_credential)
    end

    def oauth_credential
      @oauth_credential ||= OauthCredential.new(fetch_option(:oauth_token), fetch_option(:oauth_secret))
    end

    def fetch_option(name)
      @options.fetch(name) { raise ArgumentError, "#{name} is required"  }
    end
  end

  def api_key_exchange
    authenticator = TwitterAuthenticator.new(params)

    if (device = authenticator.authenticate_device)
      render :json => { :api_key => device.api_key }
    else
      render :json => { :errors => authenticator.errrors }, :status => :unprocessable_entity
    end
  end

end

I much prefer James's ActiveModel::Validation extraction:

https://gist.github.com/1243758