mastodon/app/controllers/media_proxy_controller.rb

# frozen_string_literal: true

class MediaProxyController < ApplicationController
  include RoutingHelper
  include Authorization
  include Redisable
  include Lockable

  skip_before_action :require_functional!

  before_action :authenticate_user!, if: :whitelist_mode?

  rescue_from ActiveRecord::RecordInvalid, with: :not_found
  rescue_from Mastodon::UnexpectedResponseError, with: :not_found
  rescue_from Mastodon::NotPermittedError, with: :not_found
  rescue_from HTTP::TimeoutError, HTTP::ConnectionError, OpenSSL::SSL::SSLError, with: :internal_server_error

  def show
    with_redis_lock("media_download:#{params[:id]}") do
      @media_attachment = MediaAttachment.remote.attached.find(params[:id])
      authorize @media_attachment.status, :show?
      redownload! if @media_attachment.needs_redownload? && !reject_media?
    end

    redirect_to full_asset_url(@media_attachment.file.url(version)), allow_other_host: true
  end

  private

  def redownload!
    @media_attachment.download_file!
    @media_attachment.created_at = Time.now.utc
    @media_attachment.save!
  end

  def version
    if request.path.end_with?('/small')
      :small
    else
      :original
    end
  end

  def reject_media?
    DomainBlock.reject_media?(@media_attachment.account.domain)
  end
end