def auth_by_eso( username, password )
   begin
      driver = SOAP::WSDLDriverFactory.new(ESO_WEB_SERVICE_URL).create_rpc_driver
      result = driver.Authenticate( { :username => username, :password => password} )
      result.authenticateResult == 'VALID_USER'  
   rescue
      logger.info " >> ESO authentication failed for #{params[:action]} in #{params[:id]}"
      false
   end
end  

def authenticate
   authenticate_or_request_with_http_basic do | username,password |
     return false if username.blank? || password.blank?
     username.strip!.downcase!

     # Authenticate by session cookie
     if session[:user_id]
        @current_user = User.find_by_username( session[:user_id] )
        
     # Authenticate by access list (or by calling ESO webservice)
     elsif ACCESS_LIST[ username ] == password || auth_by_eso( username, password )
        session[:user_id] = username   # Put user in session table; instant lookup next time
        @current_user = User.find_or_create_by_username( username )

     else       
        generate_render("401 Unauthorized user or incorrect password: #{username}")
        false
     end
 end
   
 def generate_render( render_msg )
   @result = render_msg
   render :text => render_msg, :status => render_msg.split(" ").first
 end