discourse/app/controllers/email_controller.rb

class EmailController < ApplicationController
  skip_before_filter :check_xhr, :preload_json
  layout 'no_ember'

  before_filter :ensure_logged_in, only: :preferences_redirect
  skip_before_filter :redirect_to_login_if_required

  def preferences_redirect
    redirect_to(email_preferences_path(current_user.username_lower))
  end

  def unsubscribe
    @user = DigestUnsubscribeKey.user_for_key(params[:key])
    RateLimiter.new(@user, "unsubscribe_via_email", 3, 1.day).performed! unless @user && @user.staff?

    # Don't allow the use of a key while logged in as a different user
    if current_user.present? && (@user != current_user)
      @different_user = true
      return
    end

    if @user.blank?
      @not_found = true
      return
    end

    if params[:from_all]
      @user.user_option.update_columns(email_always: false,
                                       email_digests: false,
                                       email_direct: false,
                                       email_private_messages: false)
    else
      @user.user_option.update_column(:email_digests, false)
    end

    @success = true
  end

  def resubscribe
    @user = DigestUnsubscribeKey.user_for_key(params[:key])
    raise Discourse::NotFound unless @user.present?
    @user.user_option.update_column(:email_digests, true)
  end

end