ruby on rails - Calling a method on User in application_helper.rb returns undefined method -

i'm trying write helper method converts floats imperial metric. have following method in application_helper.rb:

  module applicationhelper     def weight_conversion_factor       if user.measurement_units == 'metric'         0.453592       elsif user.measurement_units == 'imperial'         1       end     end   end 

if call current_user.measurement_units in view, works great. when try call user.measurement_units in application_helper.rb file, undefined methodmeasurement_units' #`

what missing here? shouldn't able call measurement_units on user within applicatoin_helper? measurement_units field in user table.

thanks!

user class, not instance. use current_user in helper method too:

module applicationhelper   def weight_conversion_factor     return nil if current_user.nil?      if current_user.measurement_units == 'metric'       0.453592     elsif current_user.measurement_units == 'imperial'       1     end   end end 

alternatively, go in user model:

class user < activerecord::base    # other code...    def weight_conversion_factor     if measurement_units == 'metric'       0.453592     elsif measurement_units == 'imperial'       1     else       nil     end   end  end