before filter example

gistfile1.txt

class StudentsController < ApplicationController

  before_filter :find_student, only: [:show, :update]

  def show
    # @student will already be loaded here
    # do whatever
  end

private

  def find_student
    if params[:id] =~ /^w/
      @student = Student.find_by_university_id(params[:id])
    else
      @student = Student.find(params[:id])
    end
  end

end