Yale CAS and user info with Rails (after security "upgrade" on LDAP)

README

Based largely on Bay Gross' Gist (https://gist.github.com/2054898), but adapted to not use LDAP (since new security features disable query by netid from external network).

Add or append these files to your Rails app to use Yale CAS Login and get user info.

application_controller.rb

# app/controllers/application_controller.rb

# Add this before filter to force CAS Authentication on all controllers + actions
before_filter CASClient::Frameworks::Rails::Filter, :unless => :skip_login?

# hack for skip_before_filter with CAS
# overwrite this method (with 'true') in any controller you want to skip CAS authentication
def skip_login? 
  false 
end

environment.rb

#
##  Add this block to the bottom of your config/environment.rb file
#

CASClient::Frameworks::Rails::Filter.configure(
  :cas_base_url => "https://secure.its.yale.edu/cas/",
  :username_session_key => :cas_user,
  :extra_attributes_session_key => :cas_extra_attributes
)

Gemfile

#
##  Add the rubycas-client gem to your Gemfile and run bundle install
#

gem 'rubycas-client'
gem 'mechanize' 
 

user.rb

# app/models/user.rb

require 'mechanize'

class User < ActiveRecord::Base
  KNOWN_AS = /^\s*Known As:\s*$/i
  EMAIL = /^\s*Email Address:\s*$/i
  YEAR = /^\s*Class Year:\s*$/i
  SCHOOL = /^\s*Division:\s*$/i
  COLLEGE = /^\s*Residential College:\s*$/i
  LEAD_SPACE = /^\s+/
  TRAIL_SPACE = /\s+$/

  before_validation :repair

  validates_uniqueness_of :email, :message => 'email address conflicts'
  validates_uniqueness_of :netid, :message => 'netid conflicts'

  def make_cas_browser
    browser = Mechanize.new
    browser.get( 'https://secure.its.yale.edu/cas/login' )
    form = browser.page.forms.first
    form.username = *****YOUR_NETID*****
    form.password = *****YOUR_PASSWORD*****
    form.submit
    browser
  end

  # update a user with the any extra available info from the yale directory
  def repair
    user_hash = self.get_user
    self.merge user_hash
  end


  def get_user
    browser = make_cas_browser
    netid = self.netid
    user_hash = {}

    browser.get("http://directory.yale.edu/phonebook/index.htm?searchString=uid%3D#{netid}")

    browser.page.search('tr').each do |tr|
      field = tr.at('th').text
      value = tr.at('td').text.sub(LEAD_SPACE, '').sub(TRAIL_SPACE, '')
      case field
      when KNOWN_AS
        user_hash[:fname] = value
      when EMAIL
        user_hash[:email] = value
        name = name_from_email(value)
        user_hash[:given_name] = name[:first]
        user_hash[:lname] = name[:last]
      when YEAR
        year = value.to_i
        user_hash[:year] = year != 0 ? year : nil
      when SCHOOL
        user_hash[:school] = value
      when COLLEGE
        user_hash[:college] = value
      end
    end

    # Use the name we got from the email if there is no "Known As" field.
    if user_hash[:given_name] && !user_hash[:fname]
      user_hash[:fname] = user_hash[:given_name]
    end

    user_hash
  end

  def merge(hash) # non-greedy merge for the user
    hash.each do |key, val|
      self[key] = val unless self[key]
    end
  end
end

users_controller.rb

# app/controllers/users_controller.rb

# authentication logic

  def login
    if session[:current_user] # already logged in
      redirect_to '/'
    elsif session[:cas_user]
      user = User.find_or_create_by_netid( session[:cas_user] )
      if user.netid && user.email # reject if we can't find an email
        session[:current_user] = user
        redirect_to '/'
      else
        redirect_to '/splash'
      end
    else # default
      redirect_to '/splash'
    end
  end

This is awesome! Just a few things if people are having issues;

Add this code to config/environment.rb

require 'casclient'
require 'casclient/frameworks/rails/filter'

CASClient::Frameworks::Rails::Filter.configure(
  :cas_base_url => "https://secure.its.yale.edu/cas/",
  :username_session_key => :cas_user,
  :extra_attributes_session_key => :cas_extra_attributes
)

If you're getting an error with the method 'configure', and RAILS_DEFAULT_LOGGER change the gem file to

gem 'rubycas-client-rails', git: "git://github.com/rubycas/rubycas-client-rails.git"
gem 'rubycas-client', '2.3.10.rc1'

If you're having SSL verification issues, go to here: http://stackoverflow.com/questions/11703679/opensslsslsslerror-on-heroku/16983443#16983443