class VCardsController < ApplicationController
  def show
    return unless params[:id]
    @office = OfficeLocation.find_with_rep(params[:id]).first
    @rep    = @office.rep

    send_data @office.v_card, filename: "#{@rep.official_full} #{@rep.state.abbr}.vcf"
  end
end

class VCardsController < ApplicationController
  def show
    @office = OfficeLocation.find_with_rep(params.require(:id)).first
    @rep    = @office.rep

    send_data @office.v_card, filename: "#{@rep.official_full} #{@rep.state.abbr}.vcf"
  end
end

Use params.require to respond with Bad Request should id parameter not be included in request
Use params.require to respond with Bad Request should id parameter not be included in request
